Forests

20 pages, 4845 KiB

Open AccessEditor’s ChoiceArticle

Chemical Signals in Tree Rings from Northern Patagonia as Indicators of Calbuco Volcano Eruptions since the 16th Century

by Lizette J. Bertin, Duncan A. Christie, Paul R. Sheppard, Ariel A. Muñoz, Antonio Lara and Claudio Alvarez

Forests 2021, 12(10), 1305; https://doi.org/10.3390/f12101305 - 25 Sep 2021

Cited by 5 | Viewed by 5783

Abstract

The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with negative impacts in Chile and Argentina, highlighting the need to determine the long-term [...] Read more.

The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with negative impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a better understanding of its eruptive frequency. We developed a continuous eruptive record of Calbuco for the 1514–2016 period by dendrochemical analysis of Fitzroya cupressoides tree rings at a biennium resolution using inductively coupled plasma–mass spectrometry. After comparing the chemical record of 20 elements contained in tree rings with historical eruptions, one group exhibited positive anomalies during (Pb/Sn) and immediately after (Mo/P/Zn/Cu) eruptions, with a Volcanic Explosivity Index (VEI) ≥ 3, and so were classified as chemical tracers of past eruptions (TPE). The tree-ring width chronology also exhibited significant decreases in tree growth associated with eruptions of VEI ≥ 3. According to these records, we identified 11 new eruptive events of Calbuco, extending its eruptive chronology back to the 16th century and determining a mean eruptive frequency of ~23 years. Our results show the potential to use dendrochemical analysis to infer past volcanic eruptions in Northern Patagonia. This information provides a long-term perspective for assessing eruptive history in Northern Patagonia, with implications for territorial planning. Full article

(This article belongs to the Special Issue Dendrochemistry: Tools for Evaluating Variations in Past and Present Forest Environments)

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18 pages, 7106 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Olive Grove Destruction by Xylella fastidiosa Bacterium on the Land Surface Temperature in Salento Detected Using Satellite Images

by Teodoro Semeraro, Riccardo Buccolieri, Marzia Vergine, Luigi De Bellis, Andrea Luvisi, Rohinton Emmanuel and Norbert Marwan

Forests 2021, 12(9), 1266; https://doi.org/10.3390/f12091266 - 16 Sep 2021

Cited by 7 | Viewed by 3265

Abstract

Agricultural activity replaces natural vegetation with cultivated land and it is a major cause of local and global climate change. Highly specialized agricultural production leads to extensive monoculture farming with a low biodiversity that may cause low landscape resilience. This is the case [...] Read more.

Agricultural activity replaces natural vegetation with cultivated land and it is a major cause of local and global climate change. Highly specialized agricultural production leads to extensive monoculture farming with a low biodiversity that may cause low landscape resilience. This is the case on the Salento peninsula, in the Apulia Region of Italy, where the Xylella fastidiosa bacterium has caused the mass destruction of olive trees, many of them in monumental groves. The historical land cover that characterized the landscape is currently in a transition phase and can strongly affect climate conditions. This study aims to analyze how the destruction of olive groves by X. fastidiosa affects local climate change. Land surface temperature (LST) data detected by Landsat 8 and MODIS satellites are used as a proxies for microclimate mitigation ecosystem services linked to the evolution of the land cover. Moreover, recurrence quantification analysis was applied to the study of LST evolution. The results showed that olive groves are the least capable forest type for mitigating LST, but they are more capable than farmland, above all in the summer when the air temperature is the highest. The differences in the average LST from 2014 to 2020 between olive groves and farmland ranges from 2.8 °C to 0.8 °C. Furthermore, the recurrence analysis showed that X. fastidiosa was rapidly changing the LST of the olive groves into values to those of farmland, with a difference in LST reduced to less than a third from the time when the bacterium was identified in Apulia six years ago. The change generated by X. fastidiosa started in 2009 and showed more or less constant behavior after 2010 without substantial variation; therefore, this can serve as the index of a static situation, which can indicate non-recovery or non-transformation of the dying olive groves. Failure to restore the initial environmental conditions can be connected with the slow progress of the uprooting and replacing infected plants, probably due to attempts to save the historic aspect of the landscape by looking for solutions that avoid uprooting the diseased plants. This suggests that social-ecological systems have to be more responsive to phytosanitary epidemics and adapt to ecological processes, which cannot always be easily controlled, to produce more resilient landscapes and avoid unwanted transformations. Full article

(This article belongs to the Special Issue Analysis of Forest Landscape and Land-Use Based on Remote Sensing Technology)

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21 pages, 3664 KiB

Open AccessEditor’s ChoiceArticle

Productivity of Eucalyptus pellita in Sumatra: Acacia mangium Legacy, Response to Phosphorus, and Site Variables for Guiding Management

by Eko B. Hardiyanto, Maydra A. Inail and E. K. Sadanandan Nambiar

Forests 2021, 12(9), 1186; https://doi.org/10.3390/f12091186 - 01 Sep 2021

Cited by 10 | Viewed by 2384

Abstract

We report on experimental studies conducted in South Sumatra with interrelated objectives to (i) examine the trends in production covering 30 years, including three rotations of Acacia mangium followed by Eucalyptus pellita which replaced A. mangium for managing the widespread threat of diseases; [...] Read more.

We report on experimental studies conducted in South Sumatra with interrelated objectives to (i) examine the trends in production covering 30 years, including three rotations of Acacia mangium followed by Eucalyptus pellita which replaced A. mangium for managing the widespread threat of diseases; (ii) understand the effects of inter-rotation slash and litter management applied to acacia (legacy effects) on E. pellita growth; (iii) assess the long term changes in the top soil layer arising from above; (iv) evaluate, through a network of experiments, across the landscape, the nature and extent of growth responses to additional phosphorus. This data was also used to explore some of the critical site and stand variables which determine the variations in productivity and responses to management. The current growth rates of E. pellita are lower than those achieved in A. mangium. The management-legacy effects by conserving site resources provides a sustainable base for the growth of E. pellita, but for further increase in productivity, additional management actions are necessary. Changes in soil pH, carbon, N and extractable P were relatively small after four rotations. Supply of P at planting gave wood volume gains at harvest, ranging from 16 to 66% across sites. The plinthite layer in the soil profile was related to productivity, with higher growth rates of E. pellita occurring when the plinthite was at deeper layers. There is much scope for increasing productivity per unit area in this landscape, and available knowledge can be synthesized into a package of best practices for application. Management should aim to improve the quality of inter-rotation management to ensure more than 90% survival, and fast growth rates during the first 2 years. We provide a framework for further research and for refining management to produce the much needed additional domestic wood supply for the local industry. Full article

(This article belongs to the Special Issue Production Sustainability of Tropical Forest Plantations)

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16 pages, 1852 KiB

Open AccessEditor’s ChoiceArticle

Effects of Spatial Boreal Forest Harvesting Practices on Efficiency through a Benchmarking Approach in Eastern Canada

by Daniela Mazo and Osvaldo Valeria

Forests 2021, 12(8), 1108; https://doi.org/10.3390/f12081108 - 19 Aug 2021

Cited by 2 | Viewed by 2213

Abstract

In eastern Canada, harvesting practices and spatial organization of harvested sites are modulated according to ecosystem forest management objectives. We determined how spatial organization affects efficiency by evaluating wood procurement costs. A comparative analysis of efficiency was presented using a non-parametric technique, i.e., [...] Read more.

In eastern Canada, harvesting practices and spatial organization of harvested sites are modulated according to ecosystem forest management objectives. We determined how spatial organization affects efficiency by evaluating wood procurement costs. A comparative analysis of efficiency was presented using a non-parametric technique, i.e., data envelopment analysis (DEA), which allows multiple variable analyses of different factors. A database of 50 harvested sites during the period 2015–2018, located along a north-south latitudinal gradient between 46° to 50°, was constructed with variables describing spatial organization (roads and dispersion of patches) and operational aspects (wood procurement costs). The evaluated financial efficiencies show high values greater than 70%. The causes of inefficiency were dispersion of the patches, distance to the mill, and the number of kilometers of built roads. When efficiency values were arranged by latitudinal location, northern sites exhibited a lower value of overall and scale efficiency due to the high values in the wood harvested, and developed road density of the zone. Full article

(This article belongs to the Special Issue Operations Research and Optimisation Techniques in Forest Management and Operations)

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10 pages, 2583 KiB

Open AccessEditor’s ChoiceArticle

Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

by Cristian Bolaño, Sabrina Palanti, Luigi Benni and Diego Moldes

Forests 2021, 12(8), 1102; https://doi.org/10.3390/f12081102 - 18 Aug 2021

Cited by 2 | Viewed by 2100

Abstract

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in [...] Read more.

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O₂, a co-factor of laccase. Full article

(This article belongs to the Special Issue Advanced Technologies in Improving the Design Life and Durability of Timber)

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17 pages, 8049 KiB

Open AccessEditor’s ChoiceArticle

Spatial Patterns of ‘Ōhi‘a Mortality Associated with Rapid ‘Ōhi‘a Death and Ungulate Presence

by Ryan L. Perroy, Timo Sullivan, David Benitez, R. Flint Hughes, Lisa M. Keith, Eva Brill, Karma Kissinger and Daniel Duda

Forests 2021, 12(8), 1035; https://doi.org/10.3390/f12081035 - 04 Aug 2021

Cited by 14 | Viewed by 5561

Abstract

Effective forest management, particularly during forest disturbance events, requires timely and accurate monitoring information at appropriate spatial scales. In Hawai‘i, widespread ‘ōhi‘a (Metrosideros polymorpha Gaud.) mortality associated with introduced fungal pathogens affects forest stands across the archipelago, further impacting native ecosystems already under [...] Read more.

Effective forest management, particularly during forest disturbance events, requires timely and accurate monitoring information at appropriate spatial scales. In Hawai‘i, widespread ‘ōhi‘a (Metrosideros polymorpha Gaud.) mortality associated with introduced fungal pathogens affects forest stands across the archipelago, further impacting native ecosystems already under threat from invasive species. Here, we share results from an integrated monitoring program based on high resolution (<5 cm) aerial imagery, field sampling, and confirmatory laboratory testing to detect and monitor ‘ōhi‘a mortality at the individual tree level across four representative sites on Hawai‘i island. We developed a custom imaging system for helicopter operations to map thousands of hectares (ha) per flight, a more useful scale than the ten to hundreds of ha typically covered using small, unoccupied aerial systems. Based on collected imagery, we developed a rating system of canopy condition to identify ‘ōhi‘a trees suspected of infection by the fungal pathogens responsible for rapid ‘ōhi‘a death (ROD); we used this system to quickly generate and share suspect tree candidate locations with partner agencies to rapidly detect new mortality outbreaks and prioritize field sampling efforts. In three of the four sites, 98% of laboratory samples collected from suspect trees assigned a high confidence rating (n = 50) and 89% of those assigned a medium confidence rating (n = 117) returned positive detections for the fungal pathogens responsible for ROD. The fourth site, which has a history of unexplained ‘ōhi‘a mortality, exhibited much lower positive detection rates: only 6% of sampled trees assigned a high confidence rating (n = 16) and 0% of the sampled suspect trees assigned a medium confidence rating (n = 20) were found to be positive for the pathogen. The disparity in positive detection rates across study sites illustrates challenges to definitively determine the cause of ‘ōhi‘a mortality from aerial imagery alone. Spatial patterns of ROD-associated ‘ōhi‘a mortality were strongly affected by ungulate presence or absence as measured by the density of suspected ROD trees in fenced (i.e., ungulate-free) and unfenced (i.e., ungulate present) areas. Suspected ROD tree densities in neighboring areas containing ungulates were two to 69 times greater than those found in ungulate-free zones. In one study site, a fence line breach occurred during the study period, and feral ungulates entered an area that was previously ungulate-free. Following the breach, suspect ROD tree densities in this area rose from 0.02 to 2.78 suspect trees/ha, highlighting the need for ungulate control to protect ‘ōhi‘a stands from Ceratocystis-induced mortality and repeat monitoring to detect forest changes and resource threats. Full article

(This article belongs to the Special Issue Assessment of the Health Status and Degradation Process of Forest Ecosystems)

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18 pages, 16167 KiB

Open AccessEditor’s ChoiceArticle

Assessing Forest Structural and Topographic Effects on Habitat Productivity for the Endangered Apennine Brown Bear

by Angela Anna Rositi, Giovanna Jona Lasinio and Paolo Ciucci

Forests 2021, 12(7), 916; https://doi.org/10.3390/f12070916 - 14 Jul 2021

Cited by 1 | Viewed by 2444

Abstract

Any forest management potentially affects the availability and quality of resources for forest-dwelling wildlife populations, including endangered species. One such species is the Apennine brown bear, a small and unique population living in the central Apennines of Italy. The conservation of this relict [...] Read more.

Any forest management potentially affects the availability and quality of resources for forest-dwelling wildlife populations, including endangered species. One such species is the Apennine brown bear, a small and unique population living in the central Apennines of Italy. The conservation of this relict bear population is hampered by the lack of knowledge of the fine-scale relationships between productivity of key foods and forest structure, as this prevents the design and implementation of effective forest management plans. To address this issue, we sampled the main structural stand attributes within the bear’s range and used multivariate generalized linear mixed models in a Bayesian framework to relate forest structural attributes to proxies of productivity of key bear foods. We found that hard mast was positively associated with both forest typology and high forest system, but negatively related to both the time elapsed since the last forest utilization and the amount of deadwood. The availability of soft-mast producing species was positively related to past forestry practices but negatively associated with steep slopes historically managed with high tree densities and a low silvicultural disturbance. Our findings also suggest that herb cover was negatively affected by terrain steepness and basal area, while herb productivity was positively affected by northern and southern exposure. Additionally, richness of forest ants was associated with forests characterized by low volume and high density. Our findings confirm that the productivity of natural bear foods is strongly affected by forest structural and topographical characteristics and are relevant as preliminary information for forest management practices to support the long-term conservation of Apennine bears. Full article

(This article belongs to the Special Issue Conservation of Threatened Forest-Dwelling Species and Intact Forest Ecosystems)

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24 pages, 15230 KiB

Open AccessEditor’s ChoiceArticle

From Acid Rain to Low Precipitation: The Role Reversal of Norway Spruce, Silver Fir, and European Beech in a Selection Mountain Forest and Its Implications for Forest Management

by Enno Uhl, Torben Hilmers and Hans Pretzsch

Forests 2021, 12(7), 894; https://doi.org/10.3390/f12070894 - 08 Jul 2021

Cited by 7 | Viewed by 2657

Abstract

Research Highlights: We make use of long term observation data from a selection forest in Bavaria. Despite the changing environmental conditions, stand level productivity remains constant over time. Maintaining species and structural diversity by forest management can contribute to resilient forest ecosystems. Background [...] Read more.

Research Highlights: We make use of long term observation data from a selection forest in Bavaria. Despite the changing environmental conditions, stand level productivity remains constant over time. Maintaining species and structural diversity by forest management can contribute to resilient forest ecosystems. Background and Objectives: Forests in mountains are similarly affected by environmental changes like those in northern latitudes as species are closer to the edge of their ecological niche. There are recent studies that report species-specific responses to climate change in unmanaged, mono-layered mountain mixed forests. We analyze how environmental changes modify the growth of multi-layered, managed selection forest, which are often targeted for stabilization and risk prevention. We pose the central hypothesis that different species-specific susceptibility to disturbances and structural diversity contribute to ecosystem stability. Materials and Methods: Based on the long-term experiment Freyung 129 in the montane zone of the Bavarian Forest, Germany we analyze long term chronologies of periodic single tree and stand growth of Norway Spruce, silver fir, and European beech in dependence of environmental factors and forest management. Results: First, we show that despite environmental changes in terms of air pollution and drought stress, productivity at stand level persists constantly because of structural diversity and species traits. Second, we show that the species-specific contribution to total stand growth and growth distribution among stem diameter classes may change over time; the species interactions balance total growth. Third, we reveal a role reversal of tree species growth pattern. N. spruce was superior in growth in the first half and was replaced by s. fir in the second half of the survey period. Fourth, we identify the interplay of different stress factors on species-specific growth as the main cause for species-specific asynchronous but growth stabilizing reaction pattern. Finally, we show that density regulation was limited in its impacts to mitigate prevailing stress factors. Conclusions: We discuss the reasons for the observed stability of productivity. We interpret results, where especially the diversity of species and structure typical for selection forests result in stable productivity and wider plateau of the density-productivity relationship, and the suitability of the selection forest concept for risk prevention and stress resilience. We conclude that species composition and stand structure of selection forestry in mixed mountain contribute to climate smart forestry. Full article

(This article belongs to the Special Issue Climate-Smart Forestry (CSF) in Mountain Regions)

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20 pages, 4485 KiB

Open AccessEditor’s ChoiceArticle

How to Evaluate Downed Fine Woody Debris Including Logging Residues?

by Nathalie Korboulewsky, Isabelle Bilger and Abdelwahab Bessaad

Forests 2021, 12(7), 881; https://doi.org/10.3390/f12070881 - 06 Jul 2021

Cited by 3 | Viewed by 2887

Abstract

Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest [...] Read more.

Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest inventories and ecological studies because they are unbiased and accurate methods. Nevertheless, most studies and inventories take into account only coarse woody debris (CWD, >10 cm in diameter), although fine woody debris (FWD) can account for a large part of the total downed biomass. We compared the LIS and FAS methods for FWD volume or biomass estimates and evaluated the influence of diameter and wood density measurements, plot number and size. We used a Test Zone (a defined surface area where a complete inventory was carried out, in addition to FAS and LIS), a Pilot Stand (a forest stand where both LIS and FAS methods were applied) and results from 10 field inventories in deciduous temperate forest stands with various conditions and amounts of FWD. Both methods, FAS and LIS, provided accurate (in trueness and precision) volume estimates, but LIS proved to be the more efficient. Diameter measurement was the main source of error: using the mean diameter, even by diameter class, led to an error for volume estimates of around 35%. On the contrary, wood density measurements can be simplified without much influence on the accuracy of biomass estimates (use of mean density by diameter class). We show that the length and number of transects greatly influences the estimates, and that it is better to apply more, shorter transects than fewer, longer ones. Finally, we determined the optimal methodology and propose a simplification of some measurements to obtain the best time-precision trade-off for FWD inventories at the stand level. Full article

(This article belongs to the Special Issue Impact of Biofuel Harvest on Nutrient and Carbon Cycles and Soil Content)

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12 pages, 2141 KiB

Open AccessEditor’s ChoiceArticle

A Test of the Relationship between Sap Flow and Evapotranspiration, Normalized via Leaf Area, under Non-Limiting Soil Moisture

by Michael A. Forster

Forests 2021, 12(7), 875; https://doi.org/10.3390/f12070875 - 02 Jul 2021

Cited by 1 | Viewed by 2191

Abstract

Sap flow is the movement of fluid within plants, whereas reference evapotranspiration (ET_o) occurs external to plants as the transfer of water vapor from a hypothetical grass crop. Yet, on daily time scales, and when soil moisture is non-limiting, sap [...] Read more.

Sap flow is the movement of fluid within plants, whereas reference evapotranspiration (ET_o) occurs external to plants as the transfer of water vapor from a hypothetical grass crop. Yet, on daily time scales, and when soil moisture is non-limiting, sap flow has a positive linear relationship with ET_o. Furthermore, the E_2.88 model hypothesises that sap flow (Q) is equal to ET_o when parameters are normalized by leaf area (A_L) via the following relationship: Q/A_L = ET_o/2.88. The value of 2.88 is the supposed leaf area index of the hypothetical grass in the ET_o model. Therefore, the E_2.88 model potentially provides a null or expected value of sap flow based on independent ET_o parameters and leaf area. A test of the E_2.88 model was conducted via three sap flow methods (dual method approach [DMA], heat ratio [HRM], and Tmax method) on the measurement of three woody species: Pyrus communis L. (var. Beurre Bosc Pear), Syzygium floribundum F. Muell. (Weeping Lilly Pilly), and Syzygium paniculatum Gaertn. (Lilly Pilly). A data compilation of the literature expanded the sample size to include additional species. The measured trees and data compilation found a strong, positive correlation between sap flow and ET_o normalized by leaf area. However, the interpretation of the results was dependent on the sap flow method. The DMA had an average accuracy of 1.6%, whereas the HRM and Tmax significantly underestimated and overestimated sap flow, respectively. This study suggested that sap flow can be reliably estimated from accurate leaf area and ET_o measurements and when other variables, such as soil moisture, are non-limiting. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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21 pages, 2212 KiB

Open AccessEditor’s ChoiceArticle

Investigating the Role of Restoration Plantings in Introducing Disease—A Case Study Using Phytophthora

by Flora Donald, Bethan V. Purse and Sarah Green

Forests 2021, 12(6), 764; https://doi.org/10.3390/f12060764 - 10 Jun 2021

Cited by 3 | Viewed by 2992

Abstract

Translocating plants to natural habitats is a long-standing conservation practice but is growing in magnitude to deliver international targets to mitigate climate change and reverse biodiversity loss. Concurrently, outbreaks of novel plant pests and pathogens are multiplying with increased global trade network connectivity [...] Read more.

Translocating plants to natural habitats is a long-standing conservation practice but is growing in magnitude to deliver international targets to mitigate climate change and reverse biodiversity loss. Concurrently, outbreaks of novel plant pests and pathogens are multiplying with increased global trade network connectivity and larger volumes of imported plants, raising concerns that restoration plantings may act as introductory disease pathways. We used UK common juniper, subject since ~1995 to conservation plantings and now experiencing significant mortality from the non-native pathogen Phytophthora austrocedri Gresl. & E. M. Hansen, as an example species to explore the availability of monitoring data that could be used to assess disease risks posed by planting. We compiled spatial records of juniper planting including qualitative data on sources of planting material, propagation settings and organization types that managed planting projects. We found that juniper planting activity expanded every decade since 1990 across the UK and while not all planting resulted in outbreaks, 19% of P. austrocedri detections were found within 2 km of a known planting. We highlight the scale and diversity of organizations raising and planting juniper, as well as the lack of source material traceability, and suggest that cross-sector collaboration and changes in practice are required to reduce the risks of pathogen introduction posed by restoration planting. Full article

(This article belongs to the Special Issue Role of Human Interventions in Spread of Soilborne Forest Pathogens and Methods for Mitigation)

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23 pages, 2630 KiB

Open AccessEditor’s ChoiceArticle

Simulating the Effects of Intensifying Silviculture on Desired Species Yields across a Broad Environmental Gradient

by Eric B. Searle, F. Wayne Bell, Guy R. Larocque, Mathieu Fortin, Jennifer Dacosta, Rita Sousa-Silva, Marco Mina and Holly D. Deighton

Forests 2021, 12(6), 755; https://doi.org/10.3390/f12060755 - 08 Jun 2021

Cited by 8 | Viewed by 3432

Abstract

In the past two decades, forest management has undergone major paradigm shifts that are challenging the current forest modelling architecture. New silvicultural systems, guidelines for natural disturbance emulation, a desire to enhance structural complexity, major advances in successional theory, and climate change have [...] Read more.

In the past two decades, forest management has undergone major paradigm shifts that are challenging the current forest modelling architecture. New silvicultural systems, guidelines for natural disturbance emulation, a desire to enhance structural complexity, major advances in successional theory, and climate change have all highlighted the limitations of current empirical models in covering this range of conditions. Mechanistic models, which focus on modelling underlying ecological processes rather than specific forest conditions, have the potential to meet these new paradigm shifts in a consistent framework, thereby streamlining the planning process. Here we use the NEBIE (a silvicultural intervention scale that classifies management intensities as natural, extensive, basic, intensive, and elite) plot network, from across Ontario, Canada, to examine the applicability of a mechanistic model, ZELIG-CFS (a version of the ZELIG tree growth model developed by the Canadian Forest Service), to simulate yields and species compositions. As silvicultural intensity increased, overall yield generally increased. Species compositions met the desired outcomes when specific silvicultural treatments were implemented and otherwise generally moved from more shade-intolerant to more shade-tolerant species through time. Our results indicated that a mechanistic model can simulate complex stands across a range of forest types and silvicultural systems while accounting for climate change. Finally, we highlight the need to improve the modelling of regeneration processes in ZELIG-CFS to better represent regeneration dynamics in plantations. While fine-tuning is needed, mechanistic models present an option to incorporate adaptive complexity into modelling forest management outcomes. Full article

(This article belongs to the Special Issue Simulation Models of the Dynamics of Forest Ecosystems)

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22 pages, 4283 KiB

Open AccessEditor’s ChoiceArticle

Developmental Dynamics of Gilbertiodendron dewevrei (Fabaceae) Drive Forest Structure and Biomass in the Eastern Congo Basin

by Henry B. Glick, Peter M. Umunay, Jean-Remy Makana, Sean C. Thomas, Jonathan D. Reuning-Scherer and Timothy G. Gregoire

Forests 2021, 12(6), 738; https://doi.org/10.3390/f12060738 - 04 Jun 2021

Cited by 3 | Viewed by 2979

Abstract

Patterns of structural change associated with monodominant tropical forest complexes have remained enigmatic for decades. Here, we extend previous efforts in presenting a longitudinal, local-scale analysis of forest dynamics in central Africa. Using four 10-ha census plots measured across three time periods (959,312 [...] Read more.

Patterns of structural change associated with monodominant tropical forest complexes have remained enigmatic for decades. Here, we extend previous efforts in presenting a longitudinal, local-scale analysis of forest dynamics in central Africa. Using four 10-ha census plots measured across three time periods (959,312 stems ≥1 cm DBH), we analyzed changes in a number of biometrical attributes for four distinct forest types capturing the developmental gradient from mixed species forest to Gilbertiodendron dewevrei-dominated forest. We modeled above-ground biomass (AGB), basal area (BA), and stem density across all species, and diameter at breast height (DBH), recruitment, and mortality for Gilbertiodendron dewevrei. We hypothesized that trends in these attributes are consistent with a slow spread of Gilbertiodendron dewevrei into adjacent mixed species forest. We identified statistically significant increases in AGB and BA across sites and positive, though nonsignificant, increases in AGB and BA for most forest types. DBH and relative recruitment increased significantly for Gilbertiodendron dewevrei stems, while relative mortality did not. When looking from mixed species to transitional to monodominant forest types, we found a statistically significant pattern of developmental aggradation and net expansion of monodominant forest. We do not attribute this to atmospheric forcing but to a combination of (a) landscape-scale recovery or response to widespread disturbance (primarily historical fires), (b) Gilbertiodendron dewevrei’s ectomycorrhizal association, and (c) Gilbertiodendron dewevrei’s exceptional stress tolerance traits. Full article

(This article belongs to the Section Forest Ecology and Management)

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18 pages, 5218 KiB

Open AccessEditor’s ChoiceArticle

sUAS for 3D Tree Surveying: Comparative Experiments on a Closed-Canopy Earthen Dam

by Cuizhen Wang, Grayson Morgan and Michael E. Hodgson

Forests 2021, 12(6), 659; https://doi.org/10.3390/f12060659 - 22 May 2021

Cited by 9 | Viewed by 2333

Abstract

Defined as “personal remote sensing”, small unmanned aircraft systems (sUAS) have been increasingly utilized for landscape mapping. This study tests a sUAS procedure of 3D tree surveying of a closed-canopy woodland on an earthen dam. Three DJI drones—Mavic Pro, Phantom 4 Pro, and [...] Read more.

Defined as “personal remote sensing”, small unmanned aircraft systems (sUAS) have been increasingly utilized for landscape mapping. This study tests a sUAS procedure of 3D tree surveying of a closed-canopy woodland on an earthen dam. Three DJI drones—Mavic Pro, Phantom 4 Pro, and M100/RedEdge-M assembly—were used to collect imagery in six missions in 2019–2020. A canopy height model was built from the sUAS-extracted point cloud and LiDAR bare earth surface. Treetops were delineated in a variable-sized local maxima filter, and tree crowns were outlined via inverted watershed segmentation. The outputs include a tree inventory that contains 238 to 284 trees (location, tree height, crown polygon), varying among missions. The comparative analysis revealed that the M100/RedEdge-M at a higher flight altitude achieved the best performance in tree height measurement (RMSE = 1 m). However, despite lower accuracy, the Phantom 4 Pro is recommended as an optimal drone for operational tree surveying because of its low cost and easy deployment. This study reveals that sUAS have good potential for operational deployment to assess tree overgrowth toward dam remediation solutions. With 3D imaging, sUAS remote sensing can be counted as a reliable, consumer-oriented tool for monitoring our ever-changing environment. Full article

(This article belongs to the Special Issue Remote Sensing Applications in Forests Inventory and Management)

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12 pages, 2020 KiB

Open AccessEditor’s ChoiceArticle

Genetic Diversity and Population Genetic Structure of Ancient Platycladus orientalis L. (Cupressaceae) in the Middle Reaches of the Yellow River by Chloroplast Microsatellite Markers

by Bei Cui, Ping Deng, Sheng Zhang and Zhong Zhao

Forests 2021, 12(5), 592; https://doi.org/10.3390/f12050592 - 09 May 2021

Cited by 6 | Viewed by 2497

Abstract

Ancient trees are famous for their life spans of hundreds or even thousands of years. These trees are rare, a testament to history and are important for scientific research. Platycladus orientalis, with the longest life span and a beautiful trunk, has become [...] Read more.

Ancient trees are famous for their life spans of hundreds or even thousands of years. These trees are rare, a testament to history and are important for scientific research. Platycladus orientalis, with the longest life span and a beautiful trunk, has become the most widely planted tree species and is believed to be sacred in China. Extensive declines in habitat area and quality pose the greatest threats to the loss of genetic diversity of ancient P. orientalis trees in the middle reaches of the Yellow River. Strengthening the protection of P. orientalis genetic resources is of great significance for the long-term development of reasonable conservation and breeding strategies. To better understand the genetic diversity and population structure of P. orientalis, we successfully analyzed four polymorphic chloroplast simple sequence repeat (cpSSR) loci and applied them to diversity and population structure analyses of 202 individuals from 13 populations in the middle reaches of the Yellow River. Based on the cpSSR data, 16 alleles were detected across 202 individuals, and a moderate level of genetic diversity was inferred from the genetic diversity parameters (H = 0.367 and A_R = 1.964). The mean pairwise genetic differentiation coefficient (Fst) between populations was 0.153, indicating relatively high genetic population differentiations. Analysis of molecular variance (AMOVA) showed that only 8% of the variation occurred among populations. Structure analysis divided the 13 P. orientalis populations into two groups with no significant geographic population structure, which was consistent with the unweighted pair group method with arithmetic mean (UPGMA) and Mantel test results. These results may indicate that transplanting and cultivation by ancient human activities are the main factors responsible for the revealed pattern of genetic differentiation of ancient P. orientalis populations. Our research is of great significance for the future establishment of protection schemes and scientific breeding of P. orientalis. Full article

(This article belongs to the Special Issue Genetic Control of Forest Tree Traits and Their Interaction with Environment)

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16 pages, 6644 KiB

Open AccessEditor’s ChoiceArticle

A STELLA-Based Model to Simultaneously Predict Hydrological Processes, N Uptake and Biomass Production in a Eucalyptus Plantation

by Ying Ouyang, Gary Feng, Heidi Renninger, Theodor D. Leininger, Prem Parajuli and Johnny M. Grace

Forests 2021, 12(5), 515; https://doi.org/10.3390/f12050515 - 21 Apr 2021

Cited by 5 | Viewed by 2742

Abstract

Eucalyptus is one of the fastest growing hardwoods for bioenergy production. Currently, few modeling tools exist to simultaneously estimate soil hydrological processes, nitrogen (N) uptake, and biomass production in a eucalyptus plantation. In this study, a STELLA (Structural Thinking and Experiential Learning Laboratory [...] Read more.

Eucalyptus is one of the fastest growing hardwoods for bioenergy production. Currently, few modeling tools exist to simultaneously estimate soil hydrological processes, nitrogen (N) uptake, and biomass production in a eucalyptus plantation. In this study, a STELLA (Structural Thinking and Experiential Learning Laboratory with Animation)-based model was developed to meet this need. After the model calibration and validation, a simulation scenario was developed to assess eucalyptus (E. grandis × urophylla) annual net primary production (ANPP), woody biomass production (WBP), water use efficiency (WUE), and N use efficiency (NUE) for a simulation period of 20 years. Simulation results showed that a typical annual variation pattern was predicted for water use, N uptake, and ANPP, increasing from spring to fall and decreasing from fall to the following winter. Overall, the average NUE during the growth stage was 700 kg/kg. To produce 1000 kg eucalyptus biomass, it required 114.84 m³ of water and 0.92 kg of N. This study suggests that the STELLA-based model is a useful tool to estimate ANPP, WBP, WUE, and NUE in a eucalyptus plantation. Full article

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19 pages, 6332 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Characterization of Dirigent Proteins in Populus: Gene Expression Variation and Expression Pattern in Response to Marssonina brunnea and Phytohormones

by Lingling Li, Weibo Sun, Peijun Zhou, Hui Wei, Pu Wang, Hongyan Li, Shamsur Rehman, Dawei Li and Qiang Zhuge

Forests 2021, 12(4), 507; https://doi.org/10.3390/f12040507 - 19 Apr 2021

Cited by 13 | Viewed by 2817

Abstract

Marssonina brunnea causes a major disease that limits poplar growth. Lignin and lignan play essential roles in protecting plants from various biological stresses. Dirigent (DIR) proteins are thought to control the stereoselective coupling of coniferyl alcohol in the formation of lignan and lignin. [...] Read more.

Marssonina brunnea causes a major disease that limits poplar growth. Lignin and lignan play essential roles in protecting plants from various biological stresses. Dirigent (DIR) proteins are thought to control the stereoselective coupling of coniferyl alcohol in the formation of lignan and lignin. DIR family members have been well studied in several plant species, but no previous detailed genome-wide analysis has been carried out in forest trees, such as poplar. We identified 40 PtDIR genes in Populus trichocarpa and classified them into three subgroups (DIR-a, DIR-b/d, and DIR-e) based on phylogenetic analyses. These genes are distributed on 11 poplar chromosomes, and 80% of PtDIRs (32/40) are intronless. The cis-element analysis inferred that PtDIRs possess many types of biological and abiotic stress-response cis-elements. We also analyzed intra- and inter-specific collinearity, which provided deep insights into the evolutionary characteristics of the poplar DIR genes. Analyses of the protein tertiary structure and critical amino acid residues showed that PtDIR7–10 and PtDIR13–16, which belong to the DIR-a subfamily, might be involved in the regio- and stereo-selectivity of bimolecular phenoxy radical coupling in poplars. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis revealed different expression patterns for the PtDIR genes of P. trichocarpa and the PeDIR genes of ‘Nanlin 895’ in various tissues. Additionally, we analyzed responses of PeDIRs to M. brunnea and different phytohormone treatments (abscisic acid, salicylic acid, methyl jasmonate, and ethylene) in ‘Nanlin 895’. The results showed that at least 18 genes responded strongly to M. brunnea, and these PeDIRs also showed significant responses to phytohormones. These results suggest that DIR genes are involved in the poplar defense response against M. brunnea, and this study will provide fundamental insights for future research on poplar DIR genes. Full article

(This article belongs to the Section Genetics and Molecular Biology)

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14 pages, 1230 KiB

Open AccessEditor’s ChoiceArticle

Rapid Detection of Pine Pathogens Lecanosticta acicola, Dothistroma pini and D. septosporum on Needles by Probe-Based LAMP Assays

by Chiara Aglietti, Colton D. Meinecke, Luisa Ghelardini, Irene Barnes, Ariska van der Nest and Caterina Villari

Forests 2021, 12(4), 479; https://doi.org/10.3390/f12040479 - 14 Apr 2021

Cited by 12 | Viewed by 3674

Abstract

Needle blights are serious needle fungal diseases affecting pines both in natural and productive forests. Among needle blight agents, the ascomycetes Lecanosticta acicola, Dothistroma pini and D. septosporum are of particular concern. These pathogens need specific, fast and accurate diagnostics since they [...] Read more.

Needle blights are serious needle fungal diseases affecting pines both in natural and productive forests. Among needle blight agents, the ascomycetes Lecanosticta acicola, Dothistroma pini and D. septosporum are of particular concern. These pathogens need specific, fast and accurate diagnostics since they are regulated species in many countries and may require differential management measures. Due to the similarities in fungal morphology and the symptoms they elicit, these species are hard to distinguish using morphological characteristics. The symptoms can also be confused with those caused by insects or abiotic agents. DNA-based detection is therefore recommended. However, the specific PCR assays that have been produced to date for the differential diagnosis of these pathogens can be applied only in a well-furnished laboratory and the procedure takes a relatively long execution time. Surveillance and forest protection would benefit from a faster diagnostic method, such as a loop-mediated isothermal amplification (LAMP) assay, which requires less sophisticated equipment and can also be deployed directly on-site using portable devices. LAMP assays for the rapid and early detection of L. acicola, D. pini and D. septosporum were developed in this work. Species-specific LAMP primers and fluorescent assimilating probes were designed for each assay, targeting the beta tubulin (β-tub2) gene for the two Dothistroma species and the elongation factor (EF-1α) region for L. acicola. Each reaction detected its respective pathogen rapidly and with high specificity and sensitivity in DNA extracts from both pure fungal cultures and directly from infected pine needles. These qualities and the compatibility with inexpensive portable instrumentation position these LAMP assays as an effective method for routine phytosanitary control of plant material in real time, and they could profitably assist the management of L. acicola, D. pini and D. septosporum. Full article

(This article belongs to the Special Issue Ecology, Identification and Management of Forest Diseases)

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9 pages, 1819 KiB

Open AccessEditor’s ChoiceArticle

Effect of Temperature and Exposure Time on Cambium Cell Viability In Vitro for Eucalyptus Species

by Yasika Medhavi Subasinghe Achchige, Liubov Volkova and Christopher J. Weston

Forests 2021, 12(4), 445; https://doi.org/10.3390/f12040445 - 06 Apr 2021

Cited by 4 | Viewed by 2711

Abstract

(1) Research Highlights: Thermal damage to cambium cells of Eucalyptus held in vitro was recorded at sublethal temperatures (40 °C–50 °C) when the duration of exposure extends beyond 2.5 min up to 5 min. (2) Background and Objectives: During a forest fire, heat [...] Read more.

(1) Research Highlights: Thermal damage to cambium cells of Eucalyptus held in vitro was recorded at sublethal temperatures (40 °C–50 °C) when the duration of exposure extends beyond 2.5 min up to 5 min. (2) Background and Objectives: During a forest fire, heat can be transferred through tree bark potentially impacting viability of vascular cambium cells and the perennial growth of the tree. With the increased temperature of the cambium, cells are known to lose viability at temperatures exceeding 60 °C. However, it is possible that extended exposure to temperatures below 60 °C may also impair cell viability. This study aimed to identify the effect of the temperature and exposure time interaction on the cambium cell viability of Eucalyptus, a genus widely distributed in natural forests and commercial plantations globally. (3) Methods: Excised cambium-phloem tissue sections from three Eucalyptus species (Messmate–E. obliqua L’Hér., Narrow-leaf peppermint–E. radiata Sieber ex DC. and Swamp gum–E. ovata Labill.) were exposed in vitro to a series of temperature–time treatments (40 °C, 50 °C, 60 °C, 70 °C for 1 min, 2.5 min, and 5 min) and tested for cell viability using a tetrazolium reduction method. (4) Results: Cell viability of cambium cells decreased with increased temperature and exposure times for all three Eucalyptus species. Longer exposure to sublethal temperatures of 40 °C to 50 °C showed statistically similar results to shorter exposure to lethal temperatures (>50 °C). (5) Conclusions: Longer exposure to sublethal temperatures (40 °C–50 °C) caused irreversible thermal damage to cambium cells of Eucalyptus when tested in vitro, further refining our understanding of raised temperature on cell viability. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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18 pages, 3012 KiB

Open AccessEditor’s ChoiceArticle

Crown Structure Explains the Discrepancy in Leaf Phenology Metrics Derived from Ground- and UAV-Based Observations in a Japanese Cool Temperate Deciduous Forest

by Noviana Budianti, Hiromi Mizunaga and Atsuhiro Iio

Forests 2021, 12(4), 425; https://doi.org/10.3390/f12040425 - 01 Apr 2021

Cited by 6 | Viewed by 2340

Abstract

Unmanned aerial vehicles (UAV) provide a new platform for monitoring crown-level leaf phenology due to the ability to cover a vast area while offering branch-level image resolution. However, below-crown vegetation, e.g., understory vegetation, subcanopy trees, and the branches of neighboring trees, along with [...] Read more.

Unmanned aerial vehicles (UAV) provide a new platform for monitoring crown-level leaf phenology due to the ability to cover a vast area while offering branch-level image resolution. However, below-crown vegetation, e.g., understory vegetation, subcanopy trees, and the branches of neighboring trees, along with the multi-layered structure of the target crown may significantly reduce the accuracy of UAV-based estimates of crown leaf phenology. To test this hypothesis, we compared UAV-derived crown leaf phenology results against those based on ground observations at the individual tree scale for 19 deciduous broad-leaved species (55 individuals in total) characterized by different crown structures. The mean crown-level green chromatic coordinate derived from UAV images poorly explained inter- and intra-species variations in spring leaf phenology, most probably due to the consistently early leaf emergence in the below-crown vegetation. The start dates for leaf expansion and end dates for leaf falling could be estimated with an accuracy of <1-week when the influence of below-crown vegetation was removed from the UAV images through visual interpretation. However, a large discrepancy between the phenological metrics derived from UAV images and ground observations was still found for the end date of leaf expansion (EOE) and start date of leaf falling (SOF). Bayesian modeling revealed that the discrepancy for EOE increased as crown length and volume increased. The crown structure was not found to contribute to the discrepancy in SOF value. Our study provides evidence that crown structure is a pivotal factor to consider when using UAV photography to reliably estimate crown leaf phenology at the individual tree-scale. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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16 pages, 3603 KiB

Open AccessEditor’s ChoiceArticle

A Novel Tree Biomass Estimation Model Applying the Pipe Model Theory and Adaptable to UAV-Derived Canopy Height Models

by Takashi Machimura, Ayana Fujimoto, Kiichiro Hayashi, Hiroaki Takagi and Satoru Sugita

Forests 2021, 12(2), 258; https://doi.org/10.3390/f12020258 - 23 Feb 2021

Cited by 10 | Viewed by 2728

Abstract

Aiming to develop a new tree biomass estimation model that is adaptable to airborne observations of forest canopies by unmanned aerial vehicles (UAVs), we applied two theories of plant form; the pipe model theory (PMT) and the statical model of plant form as [...] Read more.

Aiming to develop a new tree biomass estimation model that is adaptable to airborne observations of forest canopies by unmanned aerial vehicles (UAVs), we applied two theories of plant form; the pipe model theory (PMT) and the statical model of plant form as an extension of the PMT for tall trees. Based on these theories, tree biomass was formulated using an individual tree canopy height model derived from a UAV. The advantage of this model is that it does not depend on diameter at breast height which is difficult to observe using remote-sensing techniques. We also proposed a treetop detection method based on the fractal geometry of the crown and stand. Comparing surveys in plantations of Japanese cedar (Cryptomeria japonica D. Don) and Japanese cypress (Chamaecyparis obtusa Endl.) in Japan, the root mean square error (RMSE) of the estimated stem volume was 0.26 m³ and was smaller than or comparative to that of models using different methodologies. The significance of this model is that it contains only one empirical parameter to be adjusted which was found to be rather stable among different species and sites, suggesting the wide adaptability of the model. Finally, we demonstrated the potential applicability of the model to light detection and ranging (LiDAR) data which can provide vertical leaf density distribution. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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14 pages, 3187 KiB

Open AccessEditor’s ChoiceArticle

Influence of Agisoft Metashape Parameters on UAS Structure from Motion Individual Tree Detection from Canopy Height Models

by Wade T. Tinkham and Neal C. Swayze

Forests 2021, 12(2), 250; https://doi.org/10.3390/f12020250 - 22 Feb 2021

Cited by 35 | Viewed by 7923

Abstract

Applications of unmanned aerial systems for forest monitoring are increasing and drive a need to understand how image processing workflows impact end-user products’ accuracy from tree detection methods. Increasing image overlap and making acquisitions at lower altitudes improve how structure from motion point [...] Read more.

Applications of unmanned aerial systems for forest monitoring are increasing and drive a need to understand how image processing workflows impact end-user products’ accuracy from tree detection methods. Increasing image overlap and making acquisitions at lower altitudes improve how structure from motion point clouds represents forest canopies. However, only limited testing has evaluated how image resolution and point cloud filtering impact the detection of individual tree locations and heights. We evaluate how Agisoft Metashape’s build dense cloud Quality (image resolution) and depth map filter settings influence tree detection from canopy height models in ponderosa pine forests. Finer resolution imagery with minimal filtering provided the best visual representation of vegetation detail for trees of all sizes. These same settings maximized tree detection F-score at >0.72 for overstory (>7 m tall) and >0.60 for understory trees. Additionally, overstory tree height bias and precision improve as image resolution becomes finer. Overstory and understory tree detection in open-canopy conifer systems might be optimized using the finest resolution imagery that computer hardware enables, while applying minimal point cloud filtering. The extended processing time and data storage demands of high-resolution imagery must be balanced against small reductions in tree detection performance when down-scaling image resolution to allow the processing of greater data extents. Full article

(This article belongs to the Special Issue Forestry Applications of Unmanned Aerial Vehicles (UAVs) 2020)

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23 pages, 4439 KiB

Open AccessEditor’s ChoiceArticle

Drought and Pathogen Effects on Survival, Leaf Physiology, Oxidative Damage, and Defense in Two Middle Eastern Oak Species

by Ehsan Ghanbary, Omid Fathizadeh, Iman Pazhouhan, Mehrdad Zarafshar, Masoud Tabari, Shahram Jafarnia, Ghasem Ali Parad and Martin Karl-Friedrich Bader

Forests 2021, 12(2), 247; https://doi.org/10.3390/f12020247 - 21 Feb 2021

Cited by 17 | Viewed by 3763

Abstract

The charcoal disease agents, Biscogniauxia mediterranea and Obolarina persica are two latent, ascomycetous oak pathogens in the Middle Eastern Zagros forests, where they have devastating effects, particularly during drought. Under greenhouse conditions, we investigated the effects of the two charcoal disease agents individually [...] Read more.

The charcoal disease agents, Biscogniauxia mediterranea and Obolarina persica are two latent, ascomycetous oak pathogens in the Middle Eastern Zagros forests, where they have devastating effects, particularly during drought. Under greenhouse conditions, we investigated the effects of the two charcoal disease agents individually and in combination with drought on survival, growth, foliar gas-exchange, pigment content, oxidative stress and the antioxidant response of Quercus infectoria and Q. libani, two of the dominant tree species in this region. Commonly, the strongest negative effects emerged in the drought–pathogen interaction treatments. Q. infectoria showed less severe lesions, higher survival, more growth, and less leaf loss than Q. libani under combined biotic and abiotic stress. In both oak species, the combination of pathogen infection and drought resulted in more than 50% reduction in foliar gas-exchange parameters with partial recovery over time in Q. infectoria suggesting a superior defense system. Indeed, enhanced foliar anthocyanin, total soluble protein and glutathione concentrations imply an upregulation of the antioxidant defense system in Q. infectoria under stress while none of these parameters showed a significant treatment response in Q. libani. Consequently, Q. infectoria foliage showed no significant increase in superoxide, lower lipoxygenase activity, and less electrolyte leakage compared to the highly elevated levels seen in Q. libani indicating oxidative damage. Our findings indicate greater drought tolerance and pathogen resilience in Q. infectoria compared to Q. libani. Under future climate scenarios, we therefore expect changes in forest community structure driven by a decline in Q. libani and closely associated organisms. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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26 pages, 2187 KiB

Open AccessEditor’s ChoiceArticle

Diversity of Phytophthora Species Detected in Disturbed and Undisturbed British Soils Using High-Throughput Sequencing Targeting ITS rRNA and COI mtDNA Regions

by Blanca B. Landa, Luis F. Arias-Giraldo, Béatrice Henricot, Miguel Montes-Borrego, Lucas A. Shuttleworth and Ana Pérez-Sierra

Forests 2021, 12(2), 229; https://doi.org/10.3390/f12020229 - 17 Feb 2021

Cited by 13 | Viewed by 2978

Abstract

Disease outbreaks caused by introduced Phytophthora species have been increasing in British forests and woodlands in recent years. A better knowledge of the Phytophthora communities already present in the UK is of great importance when developing management and mitigation strategies for these diseases. [...] Read more.

Disease outbreaks caused by introduced Phytophthora species have been increasing in British forests and woodlands in recent years. A better knowledge of the Phytophthora communities already present in the UK is of great importance when developing management and mitigation strategies for these diseases. To do this, soils were sampled in “disturbed” sites, meaning sites frequently visited by the public, with recent and new plantings or soil disturbances versus more “natural” forest and woodland sites with little disturbance or management. Phytophthora diversity was assessed using high-throughput Illumina sequencing targeting the widely accepted barcoding Internal Transcribed Spacer 1 (ITS1) region of rRNA and comparing it with the mitochondrial cytochrome c oxidase I (COI) gene. Isolation of Phytophthora was run in parallel. Nothophytophthora spp. and Phytophthora spp. were detected in 79 and 41 of the 132 locations of the 14 studied sites when using ITS or COI, respectively. A total of 20 Phytophthora amplicon sequence variants (ASVs) were assigned to known Phytophthora species from eight clades (1a, 2, 2b, 3a, 5, 6b, 7a, 8b, 8c, 8d, 10a, and 10b) and 12 ASVs from six clades (1a, 2c, 3a, 3b, 6b, 7a, 8b, 8c, and 8d) when using ITS or COI, respectively. Only at two locations were the results in agreement for ITS, COI, and isolation. Additionally, 21 and 17 unknown Phytophthora phylotypes were detected using the ITS and COI, respectively. Several Phytophthora spp. within clades 7 and 8, including very important forest pathogens such as P. austrocedri and P. ramorum, were identified and found more frequently at “disturbed” sites. Additionally, eight ASVs identified as Nothophytophthora spp. were detected representing the first report of species within this new genus in Britain. Only three species not known to be present in Britain (P. castaneae, P. capsici, and P. fallax) were detected with the ITS primers and not with COI. To confirm the presence of these or any potential new Phytophthora species, sites should be re-sampled for confirmation. Additionally, there is a need to confirm if these species are a threat to British trees and try to establish any eradication measures required to mitigate Phytophthora spread in Britain. Full article

(This article belongs to the Special Issue Role of Human Interventions in Spread of Soilborne Forest Pathogens and Methods for Mitigation)

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17 pages, 2485 KiB

Open AccessEditor’s ChoiceArticle

In-Depth Genetic Diversity and Population Structure of Endangered Peruvian Amazon Rosewood Germplasm Using Genotyping by Sequencing (GBS) Technology

by Muhammad Azhar Nadeem, Stalin Juan Vasquez Guizado, Muhammad Qasim Shahid, Muhammad Amjad Nawaz, Ephrem Habyarimana, Sezai Ercişli, Fawad Ali, Tolga Karaköy, Muhammad Aasim, Rüştü Hatipoğlu, Juan Carlos Castro Gómez, Jorge Luis Marapara del Aguila, Pedro Marcelino Adrianzén Julca, Esperanza Torres Canales, Seung Hwan Yang, Gyuhwa Chung and Faheem Shehzad Baloch

Forests 2021, 12(2), 197; https://doi.org/10.3390/f12020197 - 08 Feb 2021

Cited by 7 | Viewed by 3700

Abstract

Research studies on conservative genetics of endangered plants are very important to establish the management plans for the conservation of biodiversity. Rosewood is an evergreen tree of the Amazon region and its essential oil has great acceptance in the medical and cosmetic industry. [...] Read more.

Research studies on conservative genetics of endangered plants are very important to establish the management plans for the conservation of biodiversity. Rosewood is an evergreen tree of the Amazon region and its essential oil has great acceptance in the medical and cosmetic industry. The present study aimed to explore the genetic diversity and population structure of 90 rosewood accessions collected from eight localities of Peruvian Amazon territory through DArTseq markers. A total of 7485 informative markers resulted from genotyping by sequencing (GBS) analysis were used for the molecular characterization of rosewood germplasm. Mean values of various calculated diversity parameters like observed number of alleles (1.962), the effective number of alleles (1.669), unbiased expected heterozygosity (0.411), and percent polymorphism (93.51%) over the entire germplasm showed the existence of a good level of genetic variations. Our results showed that the Mairiricay population was more diverse compared to the rest of the populations. Tamshiyacu-2 and Mairiricay-15 accessions were found genetically distinct accessions. The analysis of molecular variance (AMOVA) reflected maximum variations (75%) are due to differences within populations. The implemented clustering algorithms, i.e., STRUCTURE, neighbor-joining analysis and principal coordinate analysis (PCoA) separated the studied germplasm on the basis of their geographical locations. Diversity indices for STRUCTURE-based populations showed that subpopulation A is more diverse population than the rest of the populations, for such reason, individuals belonging to this subpopulation should be used for reintroduction or reinforcement plans of rosewood conservation. We envisage that molecular characterization of Peruvian rosewood germplasm with DArTseq markers will provide a platform for the conservation, management and restoration of endangered rosewood in upcoming years. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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15 pages, 19890 KiB

Open AccessEditor’s ChoiceArticle

Xylem and Phloem Formation Dynamics in Quercus ilex L. at a Dry Site in Southern Italy

by Angela Balzano, Katarina Čufar and Veronica De Micco

Forests 2021, 12(2), 188; https://doi.org/10.3390/f12020188 - 07 Feb 2021

Cited by 8 | Viewed by 3115

Abstract

Quercus ilex L. dieback has been recently reported at numerous Mediterranean sites. Wood and phloem formation dynamics and tree-ring series of anatomical traits can be used to evaluate growth conditions of trees. We monitored cambial activity in Q. ilex trees growing at a [...] Read more.

Quercus ilex L. dieback has been recently reported at numerous Mediterranean sites. Wood and phloem formation dynamics and tree-ring series of anatomical traits can be used to evaluate growth conditions of trees. We monitored cambial activity in Q. ilex trees growing at a site in southern Italy in order to assess how xylem and phloem production are affected by harsh seasonal climatic variation during a dry year. We followed xylogenesis by counting the number of cambial cells and detecting the occurrence of post-cambial cells throughout the year. As phloem did not show clear growth rings and boundaries between them, we followed the development of phloem fibres—their morphological traits during development and the distance from the cambium served as a reference point to evaluate the phloem production during the year. We detected a multimodal pattern in cambial activity, with wood production in three periods of the year and consequent formation of intra-annual density fluctuations (IADFs). The lowest production of xylem cells was observed in the dry late spring and summer period (likely due to the low water availability), while the highest occurred in autumn (the wettest period). Although we could not differentiate between early and late phloem, the analysis of phloem traits was useful to follow the dynamics of phloem production, which is generally difficult in Mediterranean tree species. We found cambial production of phloem throughout the year, even in the periods without xylem production. The results showed that if tree growth was constrained by environmental limitations, the ratio between xylem to phloem cells decreased and, in the most severely affected trees, more cells were formed preferentially in the phloem compared to xylem. We also briefly report the way in which to solve technical problems with tissue preparation due to extreme hardness and to the peculiar structure of Q. ilex wood and outer bark. Full article

(This article belongs to the Special Issue Wood Formation and Environmental Constraints: Multiscale Approach)

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16 pages, 10828 KiB

Open AccessEditor’s ChoiceArticle

Natural Drying and Chemical Characteristics of Hybrid Poplar Firewood Produced from Agricultural Bioenergy Buffers in Southern Québec, Canada

by Julien Fortier, Benoit Truax, Daniel Gagnon and France Lambert

Forests 2021, 12(2), 122; https://doi.org/10.3390/f12020122 - 23 Jan 2021

Cited by 3 | Viewed by 2993

Abstract

Implementing bioenergy buffers on farmland using fast-growing tree species could reduce firewood harvest pressure in woodlots and increase forest connectivity, while improving carbon sequestration, phytoremediation, stream habitats, soil stabilization and hydrological regulation. The objective of the study was to evaluate the natural drying [...] Read more.

Implementing bioenergy buffers on farmland using fast-growing tree species could reduce firewood harvest pressure in woodlots and increase forest connectivity, while improving carbon sequestration, phytoremediation, stream habitats, soil stabilization and hydrological regulation. The objective of the study was to evaluate the natural drying and chemical characteristics of hybrid poplar firewood produced from bioenergy buffers, and to compare these characteristics with those of native species harvested in adjacent woodlots. In Trial A, 110 cm-long unsplit logs (a feedstock for biomass furnaces) were produced to evaluate the effect of log diameter class on firewood quality. In this trial, hybrid poplar firewood characteristics were also compared with Populus tremuloides, Acer rubrum and Fraxinus americana. In Trial B, the effect of hybrid poplar genotype and cover treatment was evaluated on the moisture content of short split logs (40 cm long). Firewood of satisfactory quality was produced on a yearly cycle for short split logs, and on a biannual cycle for long unsplit logs. Covering short split log cords with metal sheeting lowered the final moisture content (from 20.7% to 17.3%) and reduced its variability, while genotype did not significantly affect final moisture content. In Trial A, larger-diameter logs from hybrid poplar had lower element concentrations, but slightly higher moisture content after two years. A two-fold variation in N concentration was observed between diameter classes, suggesting that burning larger poplar logs would minimize atmospheric N pollution. Heating value, carbon and calcium concentrations increased following the seasoning of hybrid poplar firewood. After the first seasoning year outdoors, hybrid poplar had the highest moisture content (33.1%) compared to native species (24.1–29.5%). However, after the second seasoning year in an unheated warehouse, the opposite was observed (14.3% for hybrid poplar vs. 15.0–21.5% for native species). Heating value, carbon and nitrogen concentrations were similar between tree species, while high phosphorus and base cation concentrations characterized hybrid poplar, suggesting higher ash production. Poplar bioenergy buffers could provide a complementary source of firewood for heating in the fall and in the spring, when the heat demand is lower than during cold winter months. Full article

(This article belongs to the Special Issue Growth and Development of Short Rotation Woody Crops for Rural and Urban Applications)

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26 pages, 2834 KiB

Open AccessEditor’s ChoiceArticle

Wood Products for Cultural Uses: Sustaining Native Resilience and Vital Lifeways in Southeast Alaska, USA

by Adelaide Johnson, Audrey E. Clavijo, Glenn Hamar, Deborah-Aanutein Head, Andrew Thoms, Wayne Price, Arianna Lapke, Justin Crotteau, Lee K. Cerveny, Hailey Wilmer, Lillian Petershoare, Andrea Cook and Sienna Reid

Forests 2021, 12(1), 90; https://doi.org/10.3390/f12010090 - 15 Jan 2021

Cited by 10 | Viewed by 5200

Abstract

Ongoing revitalization of the >5000-year-old tradition of using trees for vital culture and heritage activities including carving and weaving affirms Alaska Native resilience. However, support for these sustained cultural practices is complicated by environmental and political factors. Carving projects typically require western redcedar [...] Read more.

Ongoing revitalization of the >5000-year-old tradition of using trees for vital culture and heritage activities including carving and weaving affirms Alaska Native resilience. However, support for these sustained cultural practices is complicated by environmental and political factors. Carving projects typically require western redcedar (Thuja plicata) or yellow cedar (Callitropsis nootkatensis) trees more than 450 years of age—a tree life stage and growth rate inconsistent with current even-aged forest management strategies. Herein, we qualitatively assess the significance of wood products to rural communities and Indigenous cultures with implications for natural heritage sustainability. In partnership with Alaska Native Tribes, we engaged local youth programs to lead community discussions throughout southeast Alaska to provide specificity to the suite of cultural activities linked to regional forest lands. Results from 58 discussions across 11 southeast Alaska communities (primarily Alaska Native participants) highlighted the cultural importance of forest products including totem poles, dugout canoes, longhouses, woven hats, and woven baskets. Findings indicated spiritual well-being, health, education, tourism, and livelihood significance attributed to these products. Participant-suggested management strategies for increasing supply and expanding access to trees on public lands included: engaging local artisans in forest planning, selecting and delivering specific trees to roads as part of ongoing timber sales, allowing bark removal prior to forest-timber sales, simplifying the tree-acquisition permit process, and setting aside cultural forest groves to sustain trees seven generations into the future. By facilitating discussions, this study fostered relevant place-based youth and community engagement, benefiting youth and enhancing community knowledge transfer while simultaneously summarizing the significance of forest products for resilient culture and heritage activities. Forest management plans aiming to support Alaska Native lifeways may benefit from improved understanding of Indigenous perspectives and worldviews; designation of “culture market values” and “culture targets” can help deliver a broad array of ecosystem services. Full article

(This article belongs to the Special Issue Forest Ecosystem Services and Products)

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9 pages, 2749 KiB

Open AccessEditor’s ChoiceArticle

Penetration of Different Liquids in Wood-Based Composites: The Effect of Adsorption Energy

by Hamid R. Taghiyari, Roya Majidi, Mahnaz Ghezel Arsalan, Asaad Moradiyan, Holger Militz, George Ntalos and Antonios N. Papadopoulos

Forests 2021, 12(1), 63; https://doi.org/10.3390/f12010063 - 07 Jan 2021

Cited by 5 | Viewed by 2029

Abstract

The penetration properties of three different liquids on the surface of medium-density fiberboard (MDF) and particleboard panels were studied. Water, as a polar liquid, was compared to two other less polar liquids (namely, ethanol and kerosene) with significantly larger molecules. Measurement of penetration [...] Read more.

The penetration properties of three different liquids on the surface of medium-density fiberboard (MDF) and particleboard panels were studied. Water, as a polar liquid, was compared to two other less polar liquids (namely, ethanol and kerosene) with significantly larger molecules. Measurement of penetration time and wetted area demonstrated significantly higher values for water in comparison with the other two liquids, in both composite types. Calculation of adsorption energies, as well as adsorption distances, of the three liquid molecules on hemicellulose showed higher potentiality of water molecules in forming bonds on hemicellulose. However, comparison of the adsorption energies of cellulose with hemicellulose indicated a higher impact of the formation of bonds between hydroxyl groups in water and cellulose in hindering the penetration of water molecules into the composite textures. It was concluded that the formation of strong and stable bonds between the hydroxyl groups in water and cellulose resulted in a significant increase in penetration time and wetted area. Full article

(This article belongs to the Special Issue Composites from Recycled and Modified Woods – Technology, Properties, Application)

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12 pages, 2711 KiB

Open AccessEditor’s ChoiceArticle

Smaller and Isolated Grassland Fragments Are Exposed to Stronger Seed and Insect Predation in Habitat Edges

by Kitti Kuli-Révész, Dávid Korányi, Tamás Lakatos, Ágota Réka Szabó, Péter Batáry and Róbert Gallé

Forests 2021, 12(1), 54; https://doi.org/10.3390/f12010054 - 02 Jan 2021

Cited by 10 | Viewed by 3396

Abstract

Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment [...] Read more.

Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment size, and edge effect on insect and seed predation of arthropods. We studied 60 natural fragments of two grassland ecosystems in the same region (Hungarian Great Plain), 30 forest-steppes, and 30 burial mounds (kurgans). The size of fragments were in the range of 0.16–6.88 ha for forest-steppe and 0.01–0.44 ha for kurgan. We used 2400 sentinel arthropod preys (dummy caterpillars) and 4800 seeds in trays for the measurements. Attack marks on dummy caterpillars were used for predator identification and calculation of insect predation rates. In the case of seeds, predation rates were calculated as the number of missing or damaged seeds per total number of exposed seeds. Increasing connectivity played a role only in generally small kurgans, with a negative effect on insect and seed predation rates in the edges. In contrast, fragment size moderated edge effects on insect and seed predation rates in generally large forest-steppes. The difference between edges and centres was more pronounced in small than in large fragments. Our study emphasizes the important role of landscape and fragment-scale factors interacting with edge effect in shaping ecosystem functions in natural grassland fragments of modified landscapes. Managing functional landscapes to optimize the assessment of ecosystem functions and services needs a multispatial scale approach. Full article

(This article belongs to the Special Issue Spatial Heterogeneity of Forest-Steppes)

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19 pages, 2626 KiB

Open AccessEditor’s ChoiceArticle

Impact of Precipitation and Temperature Variability of the East Asian Summer Monsoon (EASM) on Annual Radial Increment of Selected Tree Species in Northeast China

by Sandra-Maria Hipler, Benedikt Speicher, Lars Sprengel, Hans-Peter Kahle, Heinrich Spiecker and Shuirong Wu

Forests 2020, 11(10), 1093; https://doi.org/10.3390/f11101093 - 14 Oct 2020

Cited by 3 | Viewed by 5017

Abstract

A dendroclimatological approach was used to analyze growth responses of the tree species Pinus tabuliformis Carr., Larix gmelinii Rupr., Picea asperata Mast. and Quercus mongolica Fisch. ex Ledeb. in a region of temperate climate in Northeast China. Annual radial increment (ARI) measurements from [...] Read more.

A dendroclimatological approach was used to analyze growth responses of the tree species Pinus tabuliformis Carr., Larix gmelinii Rupr., Picea asperata Mast. and Quercus mongolica Fisch. ex Ledeb. in a region of temperate climate in Northeast China. Annual radial increment (ARI) measurements from stem cross-sections were used to identify the effects of precipitation, air temperature and standardized precipitation evapotranspiration index (SPEI) on tree growth under monsoon-related conditions. We analyzed the ARI of 144 trees from 49 forest stands and applied response function and moving correlation analysis as well as a linear mixed-effects model to detect climate signal in the tree-ring series. Analyses of climate-growth relations confirmed the influence of monsoon intensities on ARI, especially in the months of May to July of the current year. Particularly in times of a weak monsoon, the preceding autumn months significantly affect the ARI. The positive effect of precipitation in times of a strong monsoon and the negative effect of air temperature-indicating increased evapotranspiration-in times of a weak monsoon alternate. An increase in drought sensitivity of the ARI was found, especially after long dry periods. The results revealed for L. gmelinii the highest climate sensitivity, with ARI more strongly influenced by precipitation in the monsoon-related months, whereas Q. mongolica was most drought tolerant and recovered quicker after growth depression. P. asperata and P. tabuliformis were located in between. Our findings provide evidence for a strong influence of the periodically fluctuating monsoon intensities on the ARI of all investigated tree species. Our results support decision-making for forest management under anticipated climate change, especially for tree species selection, in the climate sensitive region of Northeast China. Full article

(This article belongs to the Special Issue Influences of Climate Change on Range Limits and Distribution of Trees and Forests)

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16 pages, 777 KiB

Open AccessEditor’s ChoiceArticle

Transparency Index of the Supplying Countries’ Institutions and Tree Cover Loss: Determining Factors of EU Timber Imports?

by Encarnación Moral-Pajares, Concepción Martínez-Alcalá, Leticia Gallego-Valero and Ángela Andrea Caviedes-Conde

Forests 2020, 11(9), 1009; https://doi.org/10.3390/f11091009 - 19 Sep 2020

Cited by 8 | Viewed by 3106

Abstract

Illegal logging and the associated deforestation have serious consequences for biodiversity, the climate, the economy and society. The EU Timber Regulation (EUTR) prohibits the placing of illegally harvested timber or timber products on the market. The objective of this paper is to analyse [...] Read more.

Illegal logging and the associated deforestation have serious consequences for biodiversity, the climate, the economy and society. The EU Timber Regulation (EUTR) prohibits the placing of illegally harvested timber or timber products on the market. The objective of this paper is to analyse the recent evolution of EU imports of these products from the international market, in order to check how the transparency index of the supplying countries’ institutions and tree cover loss have influenced this trajectory. To that end, a panel data model is estimated with 228 observations from 38 exporting countries between 2012 and 2017. The results show that EU timber imports have a direct association with the transparency index and an inverse relationship with tree cover loss; both these relationships are highly significant at the one-percent level. Other significant factors are the performance of the EU construction sector (as a proxy for timber demand) and timber supply. In the short and medium-term, Voluntary Partnership Agreements (VPAs) signed between the EU and non-EU timber-producing countries have a negative influence on the supply to EU member states. This study presents an analysis of EU timber imports after the implementation of the EUTR, providing specific conclusions that can inform policymakers’ efforts to foster sustainable forest management. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

29 pages, 3966 KiB

Open AccessEditor’s ChoiceArticle

Forest Landscape Restoration—What Generates Failure and Success?

by Markus Höhl, Vianny Ahimbisibwe, John A. Stanturf, Peter Elsasser, Michael Kleine and Andreas Bolte

Forests 2020, 11(9), 938; https://doi.org/10.3390/f11090938 - 27 Aug 2020

Cited by 67 | Viewed by 12796

Abstract

Research Highlights: The global Forest Landscape Restoration ambitions could be impaired by projects that ignore key principles such as the engagement of local communities in decision making and implementation, equitable benefit sharing, and monitoring for adaptive management. This entails the danger of continued [...] Read more.

Research Highlights: The global Forest Landscape Restoration ambitions could be impaired by projects that ignore key principles such as the engagement of local communities in decision making and implementation, equitable benefit sharing, and monitoring for adaptive management. This entails the danger of continued degradation, disappointed local stakeholders, and ultimately, project failure. Other projects face technical problems related to tree establishment and nursery production. Background and Objectives: There are high hopes for Forest and Landscape Restoration to regain ecosystem integrity and enhance human well-being in deforested and degraded areas. We highlight various problems and success factors experienced during project implementation on a global scale. Materials and Methods: We use data from a global online survey to identify common obstacles and success factors for the implementation of forest restoration. Results: While the majority of respondents reported successful projects, others indicate drastic problems and failed projects. Major obstacles to forest restoration experienced by survey respondents were a lack of local stakeholder involvement and a mismatch between goals of local communities and restoration managers, as well as environmental, anthropogenic, and technical barriers to tree regeneration. Conclusions: When local communities, their goals, and needs are disregarded in project planning and implementation, as reported from various cases in our survey and the limited available literature, there is a risk of project failure. Failed projects and disappointed stakeholders, as well as discouraged funders and policy-makers, could lessen the momentum of global forest restoration ambitions. Adhering to key principles of Forest and Landscape Restoration can promote much-needed community support, with the potential to overcome barriers to forest regeneration and enable communities for the protection, management, and monitoring of the restored forests beyond the limited project and funding periods. Research is needed to gain a better understanding of the perception of local communities towards restoration activities. Further studies on the implementation of forest restoration at the intersection of environmental factors, socioeconomic conditions, forest regeneration/silviculture, and nursery production are needed. Full article

(This article belongs to the Section Forest Ecology and Management)

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25 pages, 5825 KiB

Open AccessEditor’s ChoiceArticle

Multi-Decadal Forest-Cover Dynamics in the Tropical Realm: Past Trends and Policy Insights for Forest Conservation in Dry Zone of Sri Lanka

by Manjula Ranagalage, M. H. J. P. Gunarathna, Thilina D. Surasinghe, Dmslb Dissanayake, Matamyo Simwanda, Yuji Murayama, Takehiro Morimoto, Darius Phiri, Vincent R. Nyirenda, K. T. Premakantha and Anura Sathurusinghe

Forests 2020, 11(8), 836; https://doi.org/10.3390/f11080836 - 01 Aug 2020

Cited by 24 | Viewed by 9909

Abstract

Forest-cover change has become an important topic in global biodiversity conservation in recent decades because of the high rates of forest loss in different parts of the world, especially in the tropical region. While human interventions are the major cause, natural disasters also [...] Read more.

Forest-cover change has become an important topic in global biodiversity conservation in recent decades because of the high rates of forest loss in different parts of the world, especially in the tropical region. While human interventions are the major cause, natural disasters also contribute to forest cover changes. During the past decades, several studies have been conducted to address different aspects of forest cover changes (e.g., drivers of deforestation, degradation, interventions) in different parts of the world. In Sri Lanka, increasing rates of forest loss have been recorded during the last 100 years on a regional basis, especially in the dry zone. However, Sri Lanka needs detailed studies that employ contemporary data and robust analytical tools to understand the patterns of forest cover changes and their drivers. The dry zone of Sri Lanka encompasses 59% of the total land area of the country, ergo, the most extensive forest cover. Our study analyzed forest cover dynamics and its drivers between 1992 and 2019. Our specific objectives included (i) producing a forest cover map for 2019, (ii) analyzing the spatiotemporal patterns of forest cover changes from 1992 to 2019, and (iii) determining the main driving forces. Landsat 8 images were used to develop forest-cover maps for 2019, and the rest of the forest cover maps (1992, 1999, and 2010) were obtained from the Forest Department of Sri Lanka. In this study, we found that the dry zone had undergone rapid forest loss (246,958.4 ha) during the past 27 years, which accounts for 8.0% of the net forest cover changes. From 2010 to 2019, the rates of forest loss were high, and this can be associated with the rapid infrastructure development of the country. The findings of this study can be used as a proxy to reform current forest policies and enhance the forest sustainability of the study area. Full article

(This article belongs to the Special Issue Forest Land Use Cover Changes (LUCC) and Impacts on Environment in South/Southeast Asian Countries)

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30 pages, 2619 KiB

Open AccessEditor’s ChoiceReview

Forest and Wellbeing: Bridging Medical and Forest Research for Effective Forest-Based Initiatives

by Ilaria Doimo, Mauro Masiero and Paola Gatto

Forests 2020, 11(8), 791; https://doi.org/10.3390/f11080791 - 22 Jul 2020

Cited by 62 | Viewed by 9615

Abstract

Research Highlights: This review gives an overview of existing literature on the emerging topic of human wellbeing-forest contact nexus and provides a preliminary framework linking forests to wellbeing by highlighting key variables affecting this relationship. Background and Objectives: Existing literature reveals the psychological, [...] Read more.

Research Highlights: This review gives an overview of existing literature on the emerging topic of human wellbeing-forest contact nexus and provides a preliminary framework linking forests to wellbeing by highlighting key variables affecting this relationship. Background and Objectives: Existing literature reveals the psychological, physiological and social wellbeing benefits of contact with forest ecosystems; however, the role of forests in this relationship remains largely unexplored. The objectives of this review are twofold: (i) to provide an overview of the contributions of forest experiences to human wellbeing and the related interplay with forest ecosystems and (ii) to identify knowledge gaps to inform future research and systematize information available for forest managers and planners to support the development of effective forest-based initiatives. Materials and Methods: A scoping review was performed with a five-phase method integrating a systematic approach on Scopus, Web of Science and PubMed databases and snowball search. Studies were analyzed using a descriptive-analytical method. Results: Overall, 93 papers were included in the review. These are mainly from health-related sciences providing limited information for forest managers, planners and practitioners. Four main underlying variables of the forest-wellbeing relationship are identified: interaction, forest features, sensorial dimension of the forest and individual traits and reactions. Conclusions: Forest-based initiatives provide good opportunities for supporting public health and time spent in contact with forests seems to have a “health-bonus”. Whether and to what extent forest management can contribute to this is still poorly investigated. There is the need to better study causal relationships between specific forest features, type of interactions, frequency and “dose” of experiences, individual reactions and needs and wellbeing effects to maximize benefits from forest-based initiatives. Full article

(This article belongs to the Special Issue The Designing and Marketing of Regulating and Cultural Forest Ecosystem Services: Successes, Failures, Lessons Learnt and Future Perspectives)

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16 pages, 2994 KiB

Open AccessEditor’s ChoicePerspective

Linking Forest Flammability and Plant Vulnerability to Drought

by Rachael H. Nolan, Chris J. Blackman, Víctor Resco de Dios, Brendan Choat, Belinda E. Medlyn, Ximeng Li, Ross A. Bradstock and Matthias M. Boer

Forests 2020, 11(7), 779; https://doi.org/10.3390/f11070779 - 20 Jul 2020

Cited by 63 | Viewed by 8687

Abstract

Globally, fire regimes are being altered by changing climatic conditions. New fire regimes have the potential to drive species extinctions and cause ecosystem state changes, with a range of consequences for ecosystem services. Despite the co-occurrence of forest fires with drought, current approaches [...] Read more.

Globally, fire regimes are being altered by changing climatic conditions. New fire regimes have the potential to drive species extinctions and cause ecosystem state changes, with a range of consequences for ecosystem services. Despite the co-occurrence of forest fires with drought, current approaches to modelling flammability largely overlook the large body of research into plant vulnerability to drought. Here, we outline the mechanisms through which plant responses to drought may affect forest flammability, specifically fuel moisture and the ratio of dead to live fuels. We present a framework for modelling live fuel moisture content (moisture content of foliage and twigs) from soil water content and plant traits, including rooting patterns and leaf traits such as the turgor loss point, osmotic potential, elasticity and leaf mass per area. We also present evidence that physiological drought stress may contribute to previously observed fuel moisture thresholds in south-eastern Australia. Of particular relevance is leaf cavitation and subsequent shedding, which transforms live fuels into dead fuels, which are drier, and thus easier to ignite. We suggest that capitalising on drought research to inform wildfire research presents a major opportunity to develop new insights into wildfires, and new predictive models of seasonal fuel dynamics. Full article

(This article belongs to the Special Issue Forest Fire Risk Prediction)

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16 pages, 1389 KiB

Open AccessEditor’s ChoicePerspective

Vitex agnus-castus L.: Main Features and Nutraceutical Perspectives

by Eliana B. Souto, Alessandra Durazzo, Amirhossein Nazhand, Massimo Lucarini, Massimo Zaccardelli, Selma B. Souto, Amelia M. Silva, Patricia Severino, Ettore Novellino and Antonello Santini

Forests 2020, 11(7), 761; https://doi.org/10.3390/f11070761 - 16 Jul 2020

Cited by 11 | Viewed by 9735

Abstract

Medicinal plants are used worldwide due to their lower risk of side effects and eco-friendly, cost-effective production when compared to chemical drugs, encouraging researchers to further exploit the therapeutic potential of the former. One of the most popular medicinal plants is Vitex agnus-castus [...] Read more.

Medicinal plants are used worldwide due to their lower risk of side effects and eco-friendly, cost-effective production when compared to chemical drugs, encouraging researchers to further exploit the therapeutic potential of the former. One of the most popular medicinal plants is Vitex agnus-castus L., grown in tropical and sub-tropical regions, to which different health benefits have already been attributed. In this perspective article, the in vitro and in vivo therapeutic properties of V. agnus-castus L. have been analyzed and reviewed with a special focus on its health-promoting effects and potential nutraceutical applications. Full article

(This article belongs to the Special Issue Forest, Foods and Nutrition)

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19 pages, 2012 KiB

Open AccessEditor’s ChoiceArticle

Challenges and Solutions for Non-Timber Forest Product Businesses in Finland–An Application of the SODA Analysis

by Jukka Tikkanen, Tuomo Takala, Marja-Liisa Järvelä, Mikko Kurttila and Henri Vanhanen

Forests 2020, 11(7), 753; https://doi.org/10.3390/f11070753 - 12 Jul 2020

Cited by 6 | Viewed by 4625

Abstract

This study aims to present a holistic image of the strategic development needs and potential solutions within the Finnish non-timber forest product (NTFP) business sector and demonstrate a new hybrid methodology for collaborative strategy formulation. The perceived challenges and solutions were collected with [...] Read more.

This study aims to present a holistic image of the strategic development needs and potential solutions within the Finnish non-timber forest product (NTFP) business sector and demonstrate a new hybrid methodology for collaborative strategy formulation. The perceived challenges and solutions were collected with the 635 group-working method in a nationwide series of NTFP actor workshops. The analysis applied the Strategic Option Development and Analysis (SODA) approach and the formal network analysis. Business actors emphasised two complex and interrelated aims of development at the core of the business activity: (1) to improve the profitability of the NTFP business and (2) to facilitate the growth of the sector. The present bottleneck is perceived in the raw material acquisition and productising, and many wider development themes, such as business logic and sustainability, received little attention. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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38 pages, 3813 KiB

Open AccessEditor’s ChoiceReview

Global Geographic Distribution and Host Range of Fusarium circinatum, the Causal Agent of Pine Pitch Canker

by Rein Drenkhan, Beccy Ganley, Jorge Martín-García, Petr Vahalík, Kalev Adamson, Katarína Adamčíková, Rodrigo Ahumada, Lior Blank, Helena Bragança, Paolo Capretti, Michelle Cleary, Carolina Cornejo, Kateryna Davydenko, Julio J. Diez, Hatice Tuğba Doğmuş Lehtijärvi, Miloň Dvořák, Rasmus Enderle, Gerda Fourie, Margarita Georgieva, Luisa Ghelardini, Jarkko Hantula, Renaud Ioos, Eugenia Iturritxa, Loukas Kanetis, Natalia N. Karpun, András Koltay, Elena Landeras, Svetlana Markovskaja, Nebai Mesanza, Ivan Milenković, Dmitry L. Musolin, Konstantinos Nikolaou, Justyna A. Nowakowska, Nikica Ogris, Funda Oskay, Tomasz Oszako, Irena Papazova-Anakieva, Marius Paraschiv, Matias Pasquali, Francesco Pecori, Trond Rafoss, Kristina Raitelaitytė, Rosa Raposo, Cecile Robin, Carlos A. Rodas, Alberto Santini, Antonio V. Sanz-Ros, Andrey V. Selikhovkin, Alejandro Solla, Mirkka Soukainen, Nikoleta Soulioti, Emma T. Steenkamp, Panaghiotis Tsopelas, Aleksandar Vemić, Anna Maria Vettraino, Michael J. Wingfield, Stephen Woodward, Cristina Zamora-Ballesteros and Martin S. Mullett Show full author list Hide full author list

Forests 2020, 11(7), 724; https://doi.org/10.3390/f11070724 - 01 Jul 2020

Cited by 40 | Viewed by 9350

Abstract

Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of [...] Read more.

Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of trees, from emerging seedlings to mature trees. Despite the importance of PPC, the global distribution of F. circinatum is poorly documented, and this problem is also true of the hosts within countries that are affected. The aim of this study was to review the global distribution of F. circinatum, with a particular focus on Europe. We considered (1) the current and historical pathogen records, both positive and negative, based on confirmed reports from Europe and globally; (2) the genetic diversity and population structure of the pathogen; (3) the current distribution of PPC in Europe, comparing published models of predicted disease distribution; and (4) host susceptibility by reviewing literature and generating a comprehensive list of known hosts for the fungus. These data were collated from 41 countries and used to compile a specially constructed geo-database. A review of 6297 observation records showed that F. circinatum and the symptoms it causes on conifers occurred in 14 countries, including four in Europe, and is absent in 28 countries. Field observations and experimental data from 138 host species revealed 106 susceptible host species including 85 Pinus species, 6 non-pine tree species and 15 grass and herb species. Our data confirm that susceptibility to F. circinatum varies between different host species, tree ages and environmental characteristics. Knowledge on the geographic distribution, host range and the relative susceptibility of different hosts is essential for disease management, mitigation and containment strategies. The findings reported in this review will support countries that are currently free of F. circinatum in implementing effective procedures and restrictions and prevent further spread of the pathogen. Full article

(This article belongs to the Special Issue Biological and Bio-Based Management of Forest Pests and Pathogens)

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24 pages, 3073 KiB

Open AccessEditor’s ChoiceReview

Co-Creating Conceptual and Working Frameworks for Implementing Forest and Landscape Restoration Based on Core Principles

by Robin L. Chazdon, Victoria Gutierrez, Pedro H. S. Brancalion, Lars Laestadius and Manuel R. Guariguata

Forests 2020, 11(6), 706; https://doi.org/10.3390/f11060706 - 24 Jun 2020

Cited by 33 | Viewed by 8811

Abstract

Existing guidelines and best-practices documents do not satisfy, at present, the need for guiding implementation of Forest and Landscape Restoration (FLR) based on core principles. Given the wide range of FLR practices and the varied spectrum of actors involved, a single working framework [...] Read more.

Existing guidelines and best-practices documents do not satisfy, at present, the need for guiding implementation of Forest and Landscape Restoration (FLR) based on core principles. Given the wide range of FLR practices and the varied spectrum of actors involved, a single working framework is unlikely to be effective, but tailored working frameworks can be co-created based on a common conceptual framework (i.e., a common core set of principles and a generalized set of criteria and indicators). We present background regarding FLR concepts, definitions, and principles, and discuss the challenges that confront effective and long-term implementation of FLR. We enumerate the many benefits that a transformative criteria and indicators framework can bring to actors and different sectors involved in restoration when such framework is anchored in the FLR principles. We justify the need to co-develop and apply specifically tailored working frameworks to help ensure that FLR interventions bring social, economic, and environmental benefits to multiple stakeholders within landscapes and adjust to changing conditions over time. Several examples of working FLR frameworks are presented to illustrate the goals and needs of communities, donors and investors, and government agencies. Transparency, feedback, communication, assessment, and adaptive management are important components of all working frameworks. Finally, we describe existing FLR guidelines and what we can learn from them. Working frameworks can be developed and used by different actors who seek to initiate an FLR process and to align restoration actions at different scales and levels. Full article

(This article belongs to the Special Issue Forest and Landscape Restoration—Making it Happen)

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14 pages, 2759 KiB

Open AccessEditor’s ChoiceArticle

Processed Baobab (Adansonia digitata L.) Food Products in Malawi: From Poor Men’s to Premium-Priced Specialty Food?

by Dietrich Darr, Chifundo Chopi-Msadala, Collins Duke Namakhwa, Kathrin Meinhold and Chimuleke Munthali

Forests 2020, 11(6), 698; https://doi.org/10.3390/f11060698 - 23 Jun 2020

Cited by 26 | Viewed by 4588

Abstract

The baobab tree (Adansonia digitata L.) is an important source of non-timber forest products in sub-Saharan Africa. Its fruits contain high amounts of vitamin C, calcium, and dietary fibre. In addition, other parts of the tree are traditionally used for human consumption, [...] Read more.

The baobab tree (Adansonia digitata L.) is an important source of non-timber forest products in sub-Saharan Africa. Its fruits contain high amounts of vitamin C, calcium, and dietary fibre. In addition, other parts of the tree are traditionally used for human consumption, particularly during lean seasons. In line with the increasing demand for natural, healthy, and nutritious food products, the baobab has great potential to contribute to human nutrition and rural livelihoods. In Malawi, where demand for baobab has substantially increased within the last decade, baobab fruits are being processed into a variety of food and non-food products, such as fruit juice, ice-lollies, sweets, and cosmetics. Yet, information on the sociodemographic background and quality preferences of baobab consumers is scanty. The current study, therefore, aimed to (1) map the diversity of baobab products available in Malawi; (2) determine consumer segments and their preferences for the most common baobab food products; and (3) examine the contribution of major attributes of processed baobab food products on their price. We employed a mixed-methods approach including the analysis of 132 baobab products and a survey of 141 consumers in formal and informal retail outlets, adopting multistage and purposive sampling. Qualitative and quantitative data were analysed using cluster analysis, cross tabulation, and hedonic regression. Results pointed to two distinct consumer segments for baobab food products, largely following the formal–informal product divide currently existing in Malawi. Both segments clearly differed with regard to preferred product attributes. We also showed that extrinsic product attributes such as packaging quality, labelling, conformity with food standards, or health claims provided distinct differentiation potential for baobab food manufacturers. In addition to providing empirical evidence for the transition of baobab food products into higher-value market segments, our results can help food processing enterprises to improve the composition and marketing of their baobab products. Full article

(This article belongs to the Special Issue Forest, Foods and Nutrition)

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8 pages, 1532 KiB

Open AccessEditor’s ChoiceConference Report

Manila Declaration on Forest and Landscape Restoration: Making It Happen

by Robin L. Chazdon, John Herbohn, Sharif A. Mukul, Nestor Gregorio, Liz Ota, Rhett D. Harrison, Patrick B. Durst, Rafael B. Chaves, Arturo Pasa, James G. Hallett, J. David Neidel, Cathy Watson and Victoria Gutierrez

Forests 2020, 11(6), 685; https://doi.org/10.3390/f11060685 - 18 Jun 2020

Cited by 22 | Viewed by 5927

Abstract

Globally, Forest and Landscape Restoration (FLR) is gaining widespread recognition from governments and policymakers for its potential to restore key ecosystem services and to improve human wellbeing. We organized an international conference on FLR, titled—Forest and Landscape Restoration: Making it Happen, between 25–27 [...] Read more.

Globally, Forest and Landscape Restoration (FLR) is gaining widespread recognition from governments and policymakers for its potential to restore key ecosystem services and to improve human wellbeing. We organized an international conference on FLR, titled—Forest and Landscape Restoration: Making it Happen, between 25–27 February 2019 in Manila, the Philippines with 139 participants from 22 countries. The Forest and Landscape Restoration Standards (FLoRES) task force also met prior to the conference, which included a field visit to a pilot community-based forest reforestation site in Biliran Island, the Philippines. Based on the three-day conference, case study presentations, and FLoRES task force meeting, we prepared the Manila Declaration on Forest and Landscape Restoration to highlight the need to support quality of FLR efforts and outcomes in the tropics. Here we provide a synthesis of the main messages of the conference, with key outcomes including the Manila Declaration on Forest and Landscape Restoration, and ways forward to make quality FLR happen on the ground. Full article

(This article belongs to the Special Issue Forest and Landscape Restoration—Making it Happen)

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21 pages, 1301 KiB

Open AccessEditor’s ChoicePerspective

Hawthorn (Crataegus spp.): An Updated Overview on Its Beneficial Properties

by Amirhossein Nazhand, Massimo Lucarini, Alessandra Durazzo, Massimo Zaccardelli, Santo Cristarella, Selma B. Souto, Amélia M. Silva, Patrícia Severino, Eliana B. Souto and Antonello Santini

Forests 2020, 11(5), 564; https://doi.org/10.3390/f11050564 - 18 May 2020

Cited by 49 | Viewed by 12687

Abstract

Medicinal plants, many of which are wild, have recently been under the spotlight worldwide due to growing requests for natural and sustainable eco-compatible remedies for pathological conditions with beneficial health effects that are able to support/supplement a daily diet or to support and/or [...] Read more.

Medicinal plants, many of which are wild, have recently been under the spotlight worldwide due to growing requests for natural and sustainable eco-compatible remedies for pathological conditions with beneficial health effects that are able to support/supplement a daily diet or to support and/or replace conventional pharmacological therapy. The main requests for these products are: safety, minimum adverse unwanted effects, better efficacy, greater bioavailability, and lower cost when compared with synthetic medications available on the market. One of these popular herbs is hawthorn (Crataegus spp.), belonging to the Rosaceae family, with about 280 species present in Europe, North Africa, West Asia, and North America. Various parts of this herb, including the berries, flowers, and leaves, are rich in nutrients and beneficial bioactive compounds. Its chemical composition has been reported to have many health benefits, including medicinal and nutraceutical properties. Accordingly, the present review gives a snapshot of the in vitro and in vivo therapeutic potential of this herb on human health. Full article

(This article belongs to the Special Issue Forest, Foods and Nutrition)

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12 pages, 2168 KiB

Open AccessEditor’s ChoiceReview

A Review of Non-Chemical Weed Control Practices in Christmas Tree Production

by Debalina Saha, Bert M. Cregg and Manjot Kaur Sidhu

Forests 2020, 11(5), 554; https://doi.org/10.3390/f11050554 - 14 May 2020

Cited by 9 | Viewed by 3414

Abstract

Weeds interfere with Christmas tree growth at any time and at any stage of production. Growers mostly rely on mechanical mowing and applications of herbicides for weed control in their fields. However, herbicides can be phytotoxic to non-target plants, can cause environment-related issues, [...] Read more.

Weeds interfere with Christmas tree growth at any time and at any stage of production. Growers mostly rely on mechanical mowing and applications of herbicides for weed control in their fields. However, herbicides can be phytotoxic to non-target plants, can cause environment-related issues, and their repeated application can even cause herbicide-resistant weeds. The main objective of this manuscript is to provide a review of non-chemical weed control strategies in Christmas tree production and identify areas where current practices could potentially be improved or in which further research is required. Preventing the introduction of weed seeds requires controlling weeds along farm roads, maintaining clean equipment, and eliminating new weeds before they start seeding. Mowing helps to reduce the number of seeds produced by the weeds and can significantly reduce competition with trees. Shropshire sheep are well suited for grazing Christmas tree plantations as they prefer grazing on grasses and weeds rather than on coniferous trees. Weeds can also be controlled around Christmas trees by mulching. Organic mulch can improve soil moisture, maintain soil temperatures, enhance root establishment and transplant survival, and improve plant establishment and overall growth. Incorporating cover crops into Christmas tree plantations may improve tree growth, quality, and soil fertility and can supplement conventional nitrogen fertilizers. However, if cover crops are not properly managed, they can be highly competitive with the trees. Flaming can cause suppression of many annual weed species but is less effective on larger weeds and needs to be applied with caution. Several insects have been used as biological agents to control selective weed species. However, further research is required to focus on several potential biological agents, different types and depths of mulches, on cover crops types and their competition with different species of Christmas trees and their effects on seedling survival and growth. Full article

(This article belongs to the Section Forest Ecology and Management)

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19 pages, 2242 KiB

Open AccessEditor’s ChoiceArticle

Plasticity of Root Traits under Competition for a Nutrient-Rich Patch Depends on Tree Species and Possesses a Large Congruency between Intra- and Interspecific Situations

by Zana A. Lak, Hans Sandén, Mathias Mayer, Douglas L. Godbold and Boris Rewald

Forests 2020, 11(5), 528; https://doi.org/10.3390/f11050528 - 09 May 2020

Cited by 8 | Viewed by 2730

Abstract

Belowground competition is an important structuring force in terrestrial plant communities. Uncertainties remain about the plasticity of functional root traits under competition, especially comparing interspecific vs. intraspecific situations. This study addresses the plasticity of fine root traits of competing Acer pseudoplatanus L. and [...] Read more.

Belowground competition is an important structuring force in terrestrial plant communities. Uncertainties remain about the plasticity of functional root traits under competition, especially comparing interspecific vs. intraspecific situations. This study addresses the plasticity of fine root traits of competing Acer pseudoplatanus L. and Fagus sylvatica L. seedlings in nutrient-rich soil patches. Seedlings’ roots were grown in a competition chamber experiment in which root growth (biomass), morphological and architectural fine roots traits, and potential activities of four extracellular enzymes were analyzed. Competition chambers with one, two conspecific, or two allospecific roots were established, and fertilized to create a nutrient ‘hotspot’. Interspecific competition significantly reduced fine root growth in Fagus only, while intraspecific competition had no significant effect on the fine root biomass of either species. Competition reduced root nitrogen concentration and specific root respiration of both species. Potential extracellular enzymatic activities of β-glucosidase (BG) and N-acetyl-glucosaminidase (NAG) were lower in ectomycorrhizal Fagus roots competing with Acer. Acer fine roots had greater diameter and tip densities under intraspecific competition. Fagus root traits were generally more plastic than those of Acer, but no differences in trait plasticity were found between competitive situations. Compared to Acer, Fagus roots possessed a greater plasticity of all studied traits but coarse root biomass. However, this high plasticity did not result in directed trait value changes under interspecific competition, but Fagus roots grew less and realized lower N concentrations in comparison to competing Acer roots. The plasticity of root traits of both species was thus found to be highly species- but not competitor-specific. By showing that both con- and allospecific roots had similar effects on target root growth and most trait values, our data sheds light on the paradigm that the intensity of intraspecific competition is greater than those of interspecific competition belowground. Full article

(This article belongs to the Special Issue Adaptation of the Root System to the Environment)

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19 pages, 1409 KiB

Open AccessEditor’s ChoiceArticle

Coconut Coir as a Sustainable Nursery Growing Media for Seedling Production of the Ecologically Diverse Quercus Species

by Barbara Mariotti, Sofia Martini, Sabrina Raddi, Andrea Tani, Douglass F. Jacobs, Juan A. Oliet and Alberto Maltoni

Forests 2020, 11(5), 522; https://doi.org/10.3390/f11050522 - 07 May 2020

Cited by 22 | Viewed by 10066

Abstract

Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut coir might provide an alternative, renewable, and reliable growing media but few studies have evaluated this media type in forest nurseries. We assessed the influence of pure coir, in combination with [...] Read more.

Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut coir might provide an alternative, renewable, and reliable growing media but few studies have evaluated this media type in forest nurseries. We assessed the influence of pure coir, in combination with various fertilization regimes, on the growth and physiology of three ecologically diverse Quercus species seedlings (Q. robur, Q. pubescens, and Q. ilex) during nursery cultivation. Seedlings were grown using peat and pure coir in combination with three fertilization treatments (standard, K-enriched, and P-enriched). Data were collected for: (1) growth and physiological traits; (2) detailed above- and below-ground morphological traits by destructive analysis; and (3) NPK content in leaves, shoot and roots, and in the growing media, following cultivation. Peat and coir in combination with the various fertilization treatments affected above- and below-ground morphology and, to a lesser extent, the physiological traits of Quercus seedlings. Large effects of the substrate occurred for most morphological variables, with peat being more effective than coir in all studied species. Fertilization also produced significant differences. The effect of K-enriched fertilization on plant growth was clear across the three species and the two growing media. P-enriched fertilization in peat was the only combination that promoted a higher amount of this element in the tissues at the end of cultivation. Despite their smaller size, seedlings produced in coir were compatible with standard Quercus forest stocktype size, and showed a proportionally higher root system development and fibrosity. Our results suggest that coir can be used as an alternative substrate to grow Quercus species seedlings, and that fertilization can offset coir deficiencies in chemical properties. As several functional traits drive planting performance under varying environmental conditions. according to the Target Plant Concept, coir might thus serve as an acceptable material for seedling cultivation in some cases. Full article

(This article belongs to the Special Issue The Scientific Basis of the Target Plant Concept)

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18 pages, 6172 KiB

Open AccessEditor’s ChoiceArticle

A Comparison of Fire Weather Indices with MODIS Fire Days for the Natural Regions of Alaska

by Robert H. Ziel, Peter A. Bieniek, Uma S. Bhatt, Heidi Strader, T. Scott Rupp and Alison York

Forests 2020, 11(5), 516; https://doi.org/10.3390/f11050516 - 03 May 2020

Cited by 18 | Viewed by 5105

Abstract

Research Highlights: Flammability of wildland fuels is a key factor influencing risk-based decisions related to preparedness, response, and safety in Alaska. However, without effective measures of current and expected flammability, the expected likelihood of active and problematic wildfires in the future is difficult [...] Read more.

Research Highlights: Flammability of wildland fuels is a key factor influencing risk-based decisions related to preparedness, response, and safety in Alaska. However, without effective measures of current and expected flammability, the expected likelihood of active and problematic wildfires in the future is difficult to assess and prepare for. This study evaluates the effectiveness of diverse indices to capture high-risk fires. Indicators of drought and atmospheric drivers are assessed along with the operational Canadian Forest Fire Danger Rating System (CFFDRS). Background and Objectives: In this study, 13 different indicators of atmospheric conditions, fuel moisture, and flammability are compared to determine how effective each is at identifying thresholds and trends for significant wildfire activity. Materials and Methods: Flammability indices are compared with remote sensing characterizations that identify where and when fire activity has occurred. Results: Among these flammability indicators, conventional tools calibrated to wildfire thresholds (Duff Moisture Code (DMC) and Buildup Index (BUI)), as well as measures of atmospheric forcing (Vapor Pressure Deficit (VPD)), performed best at representing the conditions favoring initiation and size of significant wildfire events. Conventional assessments of seasonal severity and overall landscape flammability using DMC and BUI can be continued with confidence. Fire models that incorporate BUI in overall fire potential and fire behavior assessments are likely to produce effective results throughout boreal landscapes in Alaska. One novel result is the effectiveness of VPD throughout the state, making it a potential alternative to FFMC among the short-lag/1-day indices. Conclusions: This study demonstrates the societal value of research that joins new academic research results with operational needs. Developing the framework to do this more effectively will bring science to action with a shorter lag time, which is critical as we face growing challenges from a changing climate. Full article

(This article belongs to the Section Forest Ecology and Management)

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19 pages, 5246 KiB

Open AccessEditor’s ChoiceArticle

Modeling and Monitoring of Wood Moisture Content Using Time-Domain Reflectometry

by Joseph Dahlen, Laurence Schimleck and Erik Schilling

Forests 2020, 11(4), 479; https://doi.org/10.3390/f11040479 - 24 Apr 2020

Cited by 13 | Viewed by 2837

Abstract

Time-domain reflectometry (TDR) can monitor the moisture content (MC) of water saturated logs stored in wet-decks where the MC exceeds the range that can be measured using traditional moisture meters (>50%). For this application to become routine, it is required that TDR monitoring [...] Read more.

Time-domain reflectometry (TDR) can monitor the moisture content (MC) of water saturated logs stored in wet-decks where the MC exceeds the range that can be measured using traditional moisture meters (>50%). For this application to become routine, it is required that TDR monitoring of wet-decks occurs after establishment, and tools are needed that automate data collection and analysis. We developed models that predict wood MC using three-rod epoxy encased TDR probes inserted into the transverse surface of bolts (prior wet-deck studies were installed on the tangential surface). Models were developed for southern pine, sweetgum, yellow poplar, hickory, red oak, and white oak using a Campbell Scientific TDR100. For each species, at least 37 bolts were soaked for a minimum of three months and then air dried with TDR waveforms, and MC was periodically recorded. Calibrations were developed between MC and the TDR signal using nonlinear mixed effects models. Fixed effects ranged from excellent (southern pine R² = 0.93) to poor (red oak R² = 0.36, hickory R² = 0.38). Independent of wood species, random effects all had a R² greater than 0.80, which indicates that TDR detects changes in MC at the individual sample level. Use of TDR combined with a datalogger was demonstrated in an operational wet-deck that monitored changes in MC over 12 months, and in a laboratory trial where bolts were exposed to successive wet-dry cycles over 400 days. Both applications demonstrated the utility of TDR to monitor changes in wood MC in high MC environments where periodic measurement is not feasible due to operational safety concerns. Because a saturated TDR reading indicates a saturated MC, and because of the relatively accurate random effects found here, developing individual species models is not necessary for monitoring purposes. Therefore, application of TDR monitoring can be broadly applied for wet-decks, regardless of the species stored. Full article

(This article belongs to the Section Wood Science and Forest Products)

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19 pages, 2781 KiB

Open AccessEditor’s ChoiceArticle

Coffee, Farmers, and Trees—Shifting Rights Accelerates Changing Landscapes

by Claude A. Garcia, Jérémy Vendé, Nanaya Konerira, Jenu Kalla, Michelle Nay, Anne Dray, Maëlle Delay, Patrick O. Waeber, Natasha Stoudmann, Arshiya Bose, Christophe Le Page, Yenugula Raghuram, Robert Bagchi, Jaboury Ghazoul, Cheppudira G. Kushalappa and Philippe Vaast

Forests 2020, 11(4), 480; https://doi.org/10.3390/f11040480 - 24 Apr 2020

Cited by 9 | Viewed by 4967

Abstract

Deforestation and biodiversity loss in agroecosystems are generally the result of rational choices, not of a lack of awareness or knowledge. Despite both scientific evidence and traditional knowledge that supports the value of diverse production systems for ecosystem services and resilience, a trend [...] Read more.

Deforestation and biodiversity loss in agroecosystems are generally the result of rational choices, not of a lack of awareness or knowledge. Despite both scientific evidence and traditional knowledge that supports the value of diverse production systems for ecosystem services and resilience, a trend of agroecosystem intensification is apparent across tropical regions. These transitions happen in spite of policies that prohibit such transformations. We present a participatory modelling study run to (1) understand the drivers of landscape transition and (2) explore the livelihood and environmental impacts of tenure changes in the coffee agroforestry systems of Kodagu (India). The components of the system, key actors and resources, and their interactions were defined with stakeholders, following the companion modelling (ComMod) approach. The underlying ecological processes driving the system were validated through expert knowledge and scientific literature. The conceptual model was transformed into a role-playing game and validated by eight workshops with a total of 57 participants. Two scenarios were explored, a No Policy Change as baseline, and a Restitution of Rights where rights to cut the native trees are handed over to farmers. Our results suggest that the landscape transition is likely to continue unabated unless there is a change to the current policy framework. However, the Restitution of Rights risks speeding up the process rather than reversing it, as inter alia, the differential growth rate between exotic and native tree species, kick in. Full article

(This article belongs to the Section Forest Ecology and Management)

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11 pages, 1329 KiB

Open AccessEditor’s ChoiceArticle

A Local Initiative to Achieve Global Forest and Landscape Restoration Challenge—Lessons Learned from a Community-Based Forest Restoration Project in Biliran Province, Philippines

by Nestor Gregorio, John Herbohn, Rogelio Tripoli and Arturo Pasa

Forests 2020, 11(4), 475; https://doi.org/10.3390/f11040475 - 23 Apr 2020

Cited by 18 | Viewed by 7003

Abstract

Forest and landscape restoration in the tropics is often undertaken by groups of smallholders and communities whose livelihoods are primarily agricultural and forest-based. In the Philippines, the implementation of forest restoration programs involving people’s organizations showed mixed results. We present a case study [...] Read more.

Forest and landscape restoration in the tropics is often undertaken by groups of smallholders and communities whose livelihoods are primarily agricultural and forest-based. In the Philippines, the implementation of forest restoration programs involving people’s organizations showed mixed results. We present a case study of a pilot community-based forest restoration project that was undertaken in Biliran Province to understand the impediments, and pilot test interventions to improve restoration outcomes. The project was designed using systems thinking, employing smallholder-based best-practice, and applying the principles of a participatory approach. The results revealed that the initial participation of smallholders is mostly driven by short-term financial incentives. However, long-term commitment to managing the trees is attributed mainly to sustainable livelihood, land and tree rights, equitable sharing of benefits, strong leadership, effective governance and improved human and social capitals. The support of extension officers, use of high-quality seedlings, and participation of women are essential for community-based forest restoration success. Key lessons from our research could contribute to fulfilling the forest and landscape restoration commitments of developing countries in the tropics. Full article

(This article belongs to the Special Issue Forest and Landscape Restoration—Making it Happen)

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