Forests

18 pages, 2200 KiB

Open AccessEditor’s ChoiceArticle

Eutypella parasitica and Other Frequently Isolated Fungi in Wood of Dead Branches of Young Sycamore Maple (Acer pseudoplatanus) in Slovenia

by Ana Brglez, Barbara Piškur and Nikica Ogris

Forests 2020, 11(4), 467; https://doi.org/10.3390/f11040467 - 20 Apr 2020

Cited by 7 | Viewed by 4281

Abstract

Eutypella parasitica R.W. Davidson and R.C. Lorenz is the causative agent of Eutypella canker of maple, a destructive disease of maples in Europe and North America. The fungus E. parasitica infects the trunk through a branch stub or bark wound. Because the fungal [...] Read more.

Eutypella parasitica R.W. Davidson and R.C. Lorenz is the causative agent of Eutypella canker of maple, a destructive disease of maples in Europe and North America. The fungus E. parasitica infects the trunk through a branch stub or bark wound. Because the fungal community may have an impact on infection and colonization by E. parasitica, the composition of fungi colonizing wood of dead branches of sycamore maple (Acer pseudoplatanus L.) was investigated in five sampling sites in Slovenia. Forty samples from each sampling site were collected between the November 2017 and March 2018 period. Isolations were made from the wood in the outer part of dead branches and from discoloured wood in the trunk that originated from a dead branch. Pure cultures were divided into morphotypes, and one representative culture per morphotype was selected for further molecular identification. From a total of 2700 cultured subsamples, 1744 fungal cultures were obtained, which were grouped into 212 morphotypes. The investigated samples were colonized by a broad spectrum of fungi. The most frequently isolated species were Eutypa maura (Fr.) Sacc., Eutypa sp. Tul. and C. Tul., Fusarium avenaceum (Fr.) Sacc., Neocucurbitaria acerina Wanas., Camporesi, E.B.G. Jones and K.D. Hyde and E. parasitica. In this study, we distinguished species diversity and the fungal community. There were no significant differences in the diversity of fungal species between the five sampling sites, and branch thickness did not prove to be a statistically significant factor in fungal species diversity. Nevertheless, relatively low Jaccard similarity index values suggested possible differences in the fungal communities from different sampling sites. This was confirmed by an analysis of similarities, which showed that the isolated fungal community distinctly differed between the five sampling sites and between the different isolation sources. Eutypella parasitica was isolated from all five investigated sampling sites, although Eutypella cankers were observed in only three sampling sites, indicating the possibility of asymptomatic infection. Full article

(This article belongs to the Special Issue Emerging Pathogens in Forest Ecosystems)

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11 pages, 1715 KiB

Open AccessEditor’s ChoiceArticle

The Possibility of Propolis Extract Application in Wood Protection

by Magdalena Woźniak, Patrycja Kwaśniewska-Sip, Agnieszka Waśkiewicz, Grzegorz Cofta and Izabela Ratajczak

Forests 2020, 11(4), 465; https://doi.org/10.3390/f11040465 - 20 Apr 2020

Cited by 21 | Viewed by 3723

Abstract

Nowadays, there is a growing interest in extending the service life of wood and wood products by applying natural substances that are harmless to humans and the environment. In this paper, propolis was used as an eco-friendly wood preservative. The aim of this [...] Read more.

Nowadays, there is a growing interest in extending the service life of wood and wood products by applying natural substances that are harmless to humans and the environment. In this paper, propolis was used as an eco-friendly wood preservative. The aim of this study was to determine the resistance of Scots pine wood treated with the propolis extract against brown-rot fungus Coniophora puteana. The wood biodegradation was assessed by gravimetric method, as well as by the analysis of ergosterol concentration in decayed wood and by the determination of changes in the wood structure by means of Fourier transform infrared spectroscopy. The results indicated that the impregnation of wood with propolis extract above 12% concentration limited fungal decay. The mass loss of wood treated with 18.9% propolis extract was 2.3% and was over 21 times lower than that for untreated wood. The analysis of ergosterol content and the changes in wood structure also confirmed that the propolis extract above 12% concentration protected wood against decay caused by C. puteana. Moreover, the propolis extract used in wood impregnation was rich in phenolic compounds, mainly chrysin, pinocembrin and galangin, which possess antimicrobial activity. The obtained results indicate that the extract of Polish propolis can be a promising natural wood preservative, safe for humans and the natural environment. Full article

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

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20 pages, 2629 KiB

Open AccessEditor’s ChoiceArticle

Impact of Invasive Tree Species on Natural Regeneration Species Composition, Diversity, and Density

by Marcin K. Dyderski and Andrzej M. Jagodziński

Forests 2020, 11(4), 456; https://doi.org/10.3390/f11040456 - 17 Apr 2020

Cited by 41 | Viewed by 6340

Abstract

Invasive tree species decrease ecosystem resilience with negative impacts on natural regeneration. The influence of alien tree species on ecosystems is unevenly recognized and does not always account for different habitat specificity. We assessed the impacts of the three most frequent invasive tree [...] Read more.

Invasive tree species decrease ecosystem resilience with negative impacts on natural regeneration. The influence of alien tree species on ecosystems is unevenly recognized and does not always account for different habitat specificity. We assessed the impacts of the three most frequent invasive tree species in European forests: Prunus serotina Ehrh., Quercus rubra L., and Robinia pseudoacacia L. on natural regeneration diversity, species composition, and density. We hypothesized that invaded forest types, in comparison with non-invaded, will differ in terms of species composition, will have lower taxonomic, functional, and phylogenetic diversity of natural regeneration, and will have lower densities of native tree species. We used a set of 189 study plots (200 m²) in a systematic design, established in various forest types in Wielkopolski National Park (West Poland). We analyzed impacts of forest type, accounting for soil C:N ratio, soil pH, and light availability on natural regeneration (woody species up to 0.5 m height) species composition, diversity, and density. We found an overlap of species composition among invaded and non-invaded forests and low impacts of invasive species on taxonomic diversity and functional richness. We found no impacts on phylogenetic diversity and other functional diversity components. In contrast, we found that the natural regeneration of forest-forming tree species reached lower densities in invaded than non-invaded forest types. However, sub-canopy and shrub species reached higher densities in invaded than non-invaded forest types. We confirmed that invasive tree species affect natural regeneration by decreasing the regeneration density of native tree species (in eight of nine tree species studied), species composition homogenization, and supporting natural regeneration of sub-canopy and shrub species. Therefore, the restoration of invaded forests requires eradication of invasive tree species to decrease propagule pressure and to stop decreases in the abundance of native tree species’ natural regeneration. Full article

(This article belongs to the Special Issue The Effects of Species Invasions and Dispersal on Forest Communities)

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19 pages, 2746 KiB

Open AccessEditor’s ChoiceArticle

Aiming for Sustainability and Scalability: Community Engagement in Forest Payment Schemes

by Laura F. Kowler, Arun Kumar Pratihast, Alonso Pérez Ojeda del Arco, Anne M. Larson, Christelle Braun and Martin Herold

Forests 2020, 11(4), 444; https://doi.org/10.3390/f11040444 - 15 Apr 2020

Cited by 9 | Viewed by 5123

Abstract

Community-based forest monitoring is seen as a way both to improve community engagement and participation in national environmental payment schemes and climate mitigation priorities and to implement reducing emissions from deforestation and forest degradation and foster conservation, sustainable management of forests and enhancement [...] Read more.

Community-based forest monitoring is seen as a way both to improve community engagement and participation in national environmental payment schemes and climate mitigation priorities and to implement reducing emissions from deforestation and forest degradation and foster conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries (REDD+). There is a strong assumption among community-based monitoring advocates that community monitoring is a desirable approach. However, it is unclear why community members would want to participate in their own surveillance or be involved in a program likely to limit livelihood uses of forest areas and possibly even sanction them based on the data provided. This paper explores these issues by examining three communities involved in Peru’s Conditional Direct Transfer Program, in which indigenous communities are compensated for protecting communal forests through various mechanisms, including forest monitoring. The case studies focus specifically on communities that received smartphones and were trained in their use for monitoring. The results affirm the importance that benefits outweigh the costs of local participation to sustain motivation. They also point to key factors supporting the legitimacy of the program, specifically to overcome historical tensions between the state and indigenous communities. These include the nature of engagement by program implementers and the importance of building trust over time. Full article

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

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21 pages, 2654 KiB

Open AccessEditor’s ChoiceArticle

Distance from the Forest Edge Influences Soil Fungal Communities Colonizing a Reclaimed Soil Borrow Site in Boreal Mixedwood Forest

by Tod Ramsfield, Philip-Edouard Shay, Tony Trofymow, Colin Myrholm, Bradley Tomm, Patrick Gagné and Jean Bérubé

Forests 2020, 11(4), 427; https://doi.org/10.3390/f11040427 - 09 Apr 2020

Cited by 7 | Viewed by 2553

Abstract

Soil fungi are important components of boreal forest ecosystems; for example, saprotrophic fungi regulate nutrient cycling, and mycorrhizal species facilitate nutrient uptake by plants. This study aimed to assess soil fungal communities in a reclaimed area and an adjacent natural mixedwood forest and [...] Read more.

Soil fungi are important components of boreal forest ecosystems; for example, saprotrophic fungi regulate nutrient cycling, and mycorrhizal species facilitate nutrient uptake by plants. This study aimed to assess soil fungal communities in a reclaimed area and an adjacent natural mixedwood forest and to identify the distribution of taxa available for seedling colonization. Soil fungal microbiomes were assessed along three transects (from 10 m inside the interior of the undisturbed forest to 40 m inside the reclaimed area) and in the roots of small aspen within the natural forest. Using high-throughput deoxyribonucleic acid (DNA) sequencing of internal transcribed spacer amplicons, a total of 2796 unique fungal taxa were detected across fine roots, forest floor, and mineral soils collected along the transects, whereas 166 taxa were detected in the aspen roots from the natural forest. Within the interior of the forest, ectomycorrhizal fungi were more common, whereas in the reclaimed areas, arbuscular mycorrhizae and saprophytes were more common. This survey showed that natural areas of adjacent undisturbed forest can act as a source of ectomycorrhizal fungi for dispersal into reclaimed areas. Notably, soil fungal taxa colonizing the root systems of small aspen included species that are specifically associated with soils from the undisturbed forest (primarily ectomycorrhizae) or the reclaimed clearing (saprotrophs and plant pathogens). Full article

(This article belongs to the Special Issue The Role of Mycorrhizas in Forest Structure and Dynamics)

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29 pages, 934 KiB

Open AccessEditor’s ChoiceArticle

Traditional Ecological Knowledge in Community Forest Management: Evolution and Limitations in Mexican Forest Law, Policy and Practice

by José Antonio Sierra-Huelsz, Patricia Gerez Fernández, Citlalli López Binnqüist, Louise Guibrunet and Edward A. Ellis

Forests 2020, 11(4), 403; https://doi.org/10.3390/f11040403 - 03 Apr 2020

Cited by 15 | Viewed by 5545

Abstract

Community forest management (CFM) is often a field of encounter between knowledge systems, where a conventional forestry blueprint is frequently applied in contexts rich in traditional ecological knowledge (TEK). This is the case in Mexico, a bioculturally diverse country and a reference of [...] Read more.

Community forest management (CFM) is often a field of encounter between knowledge systems, where a conventional forestry blueprint is frequently applied in contexts rich in traditional ecological knowledge (TEK). This is the case in Mexico, a bioculturally diverse country and a reference of community forestry. Based on a review of laws, policies, literature, and empirical examples, we explore technical, epistemological, political, and contextual dimensions associated with the inclusion and exclusion of TEK in CFM in Mexico. Our analysis is composed of three steps: (1) A diachronic analysis of how TEK and associated practices have been considered by federal forest laws and codes (1960–2018), (2) a diachronic analysis of the scope of conventional forestry and its evolution in time and space, and (3) situated examples illustrating the inclusion and exclusion of TEK in CFM. We argue that: (1) Legal recognition of TEK as a concept does not necessarily entail the legal recognition of all traditional management practices; (2) the inclusion of TEK in CFM is heterogeneous across communities, ecosystems, regions, products and historical trajectories; and (3) different traditional practices are not equally integrated in CFM: traditional practices that contradict the spatial segregation of activities (i.e., land sparing) favored by conventional forestry tend to be less easily accepted or ignored by government institutions. Full article

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

22 pages, 9511 KiB

Open AccessEditor’s ChoiceArticle

Change Detection and Land Suitability Analysis for Extension of Potential Forest Areas in Indonesia Using Satellite Remote Sensing and GIS

by Nety Nurda, Ryozo Noguchi and Tofael Ahamed

Forests 2020, 11(4), 398; https://doi.org/10.3390/f11040398 - 02 Apr 2020

Cited by 26 | Viewed by 5244

Abstract

The objective of this research was to detect changes in forest areas and, subsequently, the potential forest area that can be extended in the South Sumatra province of Indonesia, according to the Indonesian forest resilience classification zones. At first, multispectral satellite remote sensing [...] Read more.

The objective of this research was to detect changes in forest areas and, subsequently, the potential forest area that can be extended in the South Sumatra province of Indonesia, according to the Indonesian forest resilience classification zones. At first, multispectral satellite remote sensing datasets from Landsat 7 ETM+ and Landsat 8 OLI were classified into four classes, namely urban, vegetation, forest and waterbody to develop Land Use/Land Cover (LULC) maps for the year 2003 and 2018. Secondly, criteria, namely distance from rivers, distance from roads, elevation, LULC and settlements were selected and the reclassified maps were produced from each of the criteria for the land suitability analysis for forest extension. Thirdly, the Analytical Hierarchy Process (AHP) was incorporated to add expert opinions to prioritize the criteria referring to potential areas for forest extension. In the change detection analysis, Tourism Recreation Forest (TRF), Convertible Protection Forest (CPF) and Permanent Production Forest (PPF) forest zones had a decrease of 20%, 13% and 40% in area, respectively, in the forest class from 2003 to 2018. The Limited Production Forest (LPF) zone had large changes and decreased by 72% according to the LULC map. In the AHP method, the influential criteria had higher weights and ranked as settlements, elevation, distance from roads and distance from rivers. CPF, PPF and LPF have an opportunity for extension in the highly suitable classification (30%) and moderately suitable classification (41%) areas, to increase coverage of production forests. Wildlife Reserve Forests (WRFs) have potential for expansion in the highly suitable classification (30%) and moderately suitable classification (52%) areas, to keep biodiversity and ecosystems for wildlife resources. Nature Reserve Forests (NRFs) have an opportunity for extension in the highly suitable classification (39%) and moderately suitable classification (48%) areas, to keep the forests for nature and biodiversity. In case of TRF, there is limited scope to propose a further extension and is required to be managed with collaboration between the government and the community. Full article

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

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23 pages, 6335 KiB

Open AccessEditor’s ChoiceArticle

A Systematic Map of Agroforestry Research Focusing on Ecosystem Services in the Asia-Pacific Region

by Seongmin Shin, Khaing Thandar Soe, Haeun Lee, Tae Hoon Kim, Seongeun Lee and Mi Sun Park

Forests 2020, 11(4), 368; https://doi.org/10.3390/f11040368 - 26 Mar 2020

Cited by 37 | Viewed by 7502

Abstract

Agroforestry is an intensive land management system that integrates trees into land already used for crop and animal farming. This provides a diverse range of ecosystem services by bridging the gaps between agriculture, forestry, and animal husbandry. It is an important approach to [...] Read more.

Agroforestry is an intensive land management system that integrates trees into land already used for crop and animal farming. This provides a diverse range of ecosystem services by bridging the gaps between agriculture, forestry, and animal husbandry. It is an important approach to improve the environmental, economic, and social benefits of complex social–ecological systems in the Asia-Pacific region. This paper aims to examine the research trends in agroforestry and the current state of knowledge, as well as the research gaps in the ecosystem services of agroforestry in this region. A systematic mapping methodology was applied, where analysis units were academic articles related to agroforestry practices in the Asia-Pacific region. The articles published between 1970 and 2018 were collected through the international specialized academic database, SCOPUS. They were coded according to the types of agroforestry practices and ecosystem services. The research result indicates silvorable systems, especially plantation crop combinations, tree management, habitats for species, biological controls, and maintenance of genetic diversity and gene-pools, are the most prominent in the agroforestry research from the Asia-Pacific region. Approximately 60% of all research articles include case studies from India, China, Indonesia, and Australia. Research on agroforestry has changed following the international discourse on climate change and biodiversity. Therefore, this systematic map improves our understanding of the nature, volume, and characteristics of the research on ecosystem services with regard to agroforestry in the Asia-Pacific region. It provides scholars with a springboard for further meta-analysis or research on agroforestry and ecosystem services. Full article

(This article belongs to the Special Issue Systematic Approach to Agroforestry Policies and Practices in Asia)

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18 pages, 2153 KiB

Open AccessEditor’s ChoiceArticle

Characterizing over Four Decades of Forest Disturbance in Minnesota, USA

by Jody C. Vogeler, Robert A. Slesak, Patrick A. Fekety and Michael J. Falkowski

Forests 2020, 11(3), 362; https://doi.org/10.3390/f11030362 - 24 Mar 2020

Cited by 26 | Viewed by 4629

Abstract

Spatial information about disturbance driven patterns of forest structure and ages across landscapes provide a valuable resource for all land management efforts including cross-ownership collaborative forest treatments and restoration. While disturbance events in general are known to impact stand characteristics, the agent of [...] Read more.

Spatial information about disturbance driven patterns of forest structure and ages across landscapes provide a valuable resource for all land management efforts including cross-ownership collaborative forest treatments and restoration. While disturbance events in general are known to impact stand characteristics, the agent of change may also influence recovery and the supply of ecosystem services. Our study utilizes the full extent of the Landsat archive to identify the timing, extent, magnitude, and agent, of the most recent fast disturbance event for all forested lands within Minnesota, USA. To account for the differences in the Landsat sensors through time, specifically the coarser spatial, spectral, and radiometric resolutions of the early MSS sensors, we employed a two-step approach, first harmonizing spectral indices across the Landsat sensors, then applying a segmentation algorithm to fit temporal trends to the time series to identify abrupt forest disturbance events. We further incorporated spectral, topographic, and land protection information in our classification of the agent of change for all disturbance patches. After allowing two years for the time series to stabilize, we were able to identify the most recent fast disturbance events across Minnesota from 1974–2018 with a change versus no-change validation accuracy of 97.2% ± 1.9%, and higher omission (14.9% ± 9.3%) than commission errors (1.6% ± 1.9%) for the identification of change patches. Our classification of the agent of change exhibited an overall accuracy of 96.5% ± 1.9% with classes including non-disturbed forest, land conversion, fire, flooding, harvest, wind/weather, and other rare natural events. Individual class errors varied, but all class user and producer accuracies were above 78%. The unmatched nature of the Landsat archive for providing comparable forest attribute and change information across more than four decades highlights the value of the totality of the Landsat program to the larger geospatial, ecological research, and forest management communities. Full article

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

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27 pages, 2963 KiB

Open AccessEditor’s ChoiceArticle

Combining Climate Change Mitigation Scenarios with Current Forest Owner Behavior: A Scenario Study from a Region in Southern Sweden

by Isak Lodin, Ljusk Ola Eriksson, Nicklas Forsell and Anu Korosuo

Forests 2020, 11(3), 346; https://doi.org/10.3390/f11030346 - 20 Mar 2020

Cited by 10 | Viewed by 5895

Abstract

This study investigates the need for change of current forest management approaches in a southern Swedish region within the context of future climate change mitigation through empirically derived projections, rather than forest management according to silvicultural guidelines. Scenarios indicate that climate change mitigation [...] Read more.

This study investigates the need for change of current forest management approaches in a southern Swedish region within the context of future climate change mitigation through empirically derived projections, rather than forest management according to silvicultural guidelines. Scenarios indicate that climate change mitigation will increase global wood demand. This might call for adjustments of well-established management approaches. This study investigates to what extent increasing wood demands in three climate change mitigation scenarios can be satisfied with current forest management approaches of different intensities in a southern Swedish region. Forest management practices in Kronoberg County were mapped through interviews, statistics, and desk research and were translated into five different management strategies with different intensities regulating management at the property level. The consequences of current practices, as well as their intensification, were analyzed with the Heureka Planwise forest planning system in combination with a specially developed forest owner decision simulator. Projections were done over a 100-year period under three climate change mitigation scenarios developed with the Global Biosphere Management Model (GLOBIUM). Current management practices could meet scenario demands during the first 20 years. This was followed by a shortage of wood during two periods in all scenarios unless rotations were reduced. In a longer timeframe, the wood demands were projected to be easily satisfied in the less ambitious climate change mitigation scenarios. In contrast, the demand in the ambitious mitigation scenario could not be met with current management practices, not even if all owners managed their production forests at the intensive extreme of current management approaches. The climate change mitigation scenarios provide very different trajectories with respect to future drivers of forest management. Our results indicate that with less ambitious mitigation efforts, the relatively intensive practices in the study region can be softened while ambitious mitigation might push for further intensification. Full article

(This article belongs to the Special Issue Decision Support to Address Multiple Ecosystem Services in Forest Management Planning)

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24 pages, 1865 KiB

Open AccessEditor’s ChoiceReview

Stand Structural Characteristics Are the Most Practical Biodiversity Indicators for Forest Management Planning in Europe

by Marija Ćosović, Miguel N. Bugalho, Dominik Thom and José G. Borges

Forests 2020, 11(3), 343; https://doi.org/10.3390/f11030343 - 19 Mar 2020

Cited by 33 | Viewed by 8477

Abstract

Including biodiversity assessments in forest management planning is becoming increasingly important due to the importance of biodiversity for forest ecosystem resilience provision and sustainable functioning. Here we investigated the potential to include biodiversity indicators into forest management planning in Europe. In particular, we [...] Read more.

Including biodiversity assessments in forest management planning is becoming increasingly important due to the importance of biodiversity for forest ecosystem resilience provision and sustainable functioning. Here we investigated the potential to include biodiversity indicators into forest management planning in Europe. In particular, we aimed to (i) identify biodiversity indicators and data collection methods for biodiversity assessments at the stand and landscape levels, and (ii) evaluate the practicality of those indicators for forest management planning. We performed a literature review in which we screened 188 research studies published between 1990 and 2020. We selected 94 studies that fulfilled the inclusion criteria and examined in more detail. We considered three aspects of biodiversity: structure, composition, and function, and four forest management categories: unmanaged, managed, plantation, and silvopastoral. We used three criteria to evaluate the practicality of forest biodiversity indicators: cost-effectiveness, ease of application, and time-effectiveness. We identified differences in the practicality of biodiversity indicators for their incorporation into management plans. Stand-level indicators are more practical than landscape-level indicators. Moreover, structural biodiversity indicators (e.g., large trees, canopy openness, and old forest stands) are more useful in management plans than compositional indicators, as these are easily observable by non-professionals and can be obtained by forest inventories. Compositional indicators such are vascular plants, fungi, bryophyte, lichens, and invertebrate species are hard to identify by non-professionals and thus are impractical. Functional indicators (e.g., nutrient cycling) are not sufficiently addressed in the literature. Using recently updated existing databases (e.g., national forest inventories and bird atlases) is very time and cost-efficient. Remote sensing and other technology (e.g., smartphone applications) are promising for efficient data collection in the future. However, more research is needed to make these tools more accurate and applicable to a variety of ecological conditions and scales. Until then, forest stand structural variables derived from inventories can help improve management plans to prepare European forests towards an uncertain future. Full article

(This article belongs to the Special Issue Forest Structural Characteristics and Their Relationship with Ecosystem Services and Functions)

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18 pages, 2940 KiB

Open AccessEditor’s ChoiceArticle

The State of British Columbia’s Forests: A Global Comparison

by Haris R. Gilani and John L. Innes

Forests 2020, 11(3), 316; https://doi.org/10.3390/f11030316 - 13 Mar 2020

Cited by 11 | Viewed by 7607

Abstract

The Forest Resources Assessment 2015 is a comprehensive dataset from the Food and Agriculture Organization of the United Nations (FAO), which provides the opportunity to explore some of the emerging topics related to sustainable forest management. This paper assesses how forests in British [...] Read more.

The Forest Resources Assessment 2015 is a comprehensive dataset from the Food and Agriculture Organization of the United Nations (FAO), which provides the opportunity to explore some of the emerging topics related to sustainable forest management. This paper assesses how forests in British Columbia, Canada, compare globally on several key sustainable forest management parameters in four domains—biophysical indicators and legal framework, management plans, data management, and stakeholder involvement. The comparison was done against eight jurisdictions, namely Australia, China, Japan, the European Union, New Zealand, the Russian Federation and the USA. To accomplish our objectives, country-specific data on sustainable forest management parameters were extracted from the 2015 FAO’s Global Forest Resources Assessment (FRA). Data specific to B.C. were sourced from Canada’s National Forest Inventory, and National Forest Database. Our results showed that British Columbia (B.C.) has one of the highest proportions of land covered with forests (57%) among all jurisdictions. The total forest area in B.C. has remained stable at around 55 million ha. The current rate of deforestation (6200 ha per year) is among the lowest in all jurisdictions. Data on the extent of primary forests in B.C. is unavailable. However, 22.6 million ha (41% of B.C.′s forests) have been classified as old growth forests (using a definition unique to B.C.). B.C. is the leading provincial forest producer by volume, and produced 67.97 million m³ of roundwood in 2015. With approximately 11 billion m³ of standing timber, roundwood production volume has held steady since 1990. In British Columbia, the National Forest Inventory—British Columbia Program (NFI-B.C.) is used to track and monitor the current status of the forests. It involves both ground plots and remote sensing. The most recent B.C. State of the Forests is one of the most comprehensive reports among all jurisdictions, using 24 topic areas, with each topic comprising several indicators of sustainable forest management. We conclude that British Columbia ranks high among other jurisdictions on several key sustainable forest management parameters with legislation and forest management regimes aiming to meet the environmental, social and economic needs of current and future generations. Full article

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

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10 pages, 986 KiB

Open AccessEditor’s ChoiceBrief Report

A Four-Year, Seven-State Reforestation Trial with Eastern Hemlocks (Tsuga canadensis) Resistant to Hemlock Woolly Adelgid (Adelges tsugae)

by Ian G. Kinahan, Gabrielle Grandstaff, Alana Russell, Chad M. Rigsby, Richard A. Casagrande and Evan L. Preisser

Forests 2020, 11(3), 312; https://doi.org/10.3390/f11030312 - 12 Mar 2020

Cited by 4 | Viewed by 4871

Abstract

We conducted over a decade of research into individual eastern hemlock (Tsuga canadensis; hemlock) trees that are potentially resistant to hemlock woolly adelgid (Adelges tsugae; HWA), an invasive xylem-feeding insect that is capable of rapidly killing even mature trees. [...] Read more.

We conducted over a decade of research into individual eastern hemlock (Tsuga canadensis; hemlock) trees that are potentially resistant to hemlock woolly adelgid (Adelges tsugae; HWA), an invasive xylem-feeding insect that is capable of rapidly killing even mature trees. Following clonal propagation of these individuals, in 2015 we planted size- and age-matched HWA-resistant and HWA-susceptible hemlocks in HWA-infested forest plots in seven states. In 2019, we re-surveyed the plots; 96% of HWA-resistant hemlocks survived compared to 48% of susceptible trees. The surviving HWA-resistant trees were also taller, produced more lateral growth, retained more foliage, and supported lower densities of the elongate hemlock scale Fiorinia externa, another invasive hemlock pest, than the surviving HWA-susceptible trees. Our results suggest that HWA management may benefit from additional research exploring the identification, characterization, and use of HWA-resistant eastern hemlocks in future reforestation efforts. Full article

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

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16 pages, 3611 KiB

Open AccessEditor’s ChoiceArticle

Effect of Temperature, Light, and Storage Time on the Seed Germination of Pinus bungeana Zucc. ex Endl.: The Role of Seed-Covering Layers and Abscisic Acid Changes

by Congcong Guo, Yongbao Shen and Fenghou Shi

Forests 2020, 11(3), 300; https://doi.org/10.3390/f11030300 - 08 Mar 2020

Cited by 27 | Viewed by 4981

Abstract

Pinus bungeana Zucc. ex Endl. is an endemic conifer tree species in China with high ornamental value. In order to investigate favorable conditions for seed germination and explore the germination inhibition mechanism of this species at high temperatures, the effects of temperature, light, [...] Read more.

Pinus bungeana Zucc. ex Endl. is an endemic conifer tree species in China with high ornamental value. In order to investigate favorable conditions for seed germination and explore the germination inhibition mechanism of this species at high temperatures, the effects of temperature, light, and storage on the mean germination time (MGT), speed of germination (SG), and total germination percentage (TGP) are evaluated here. Seeds that have either been kept still or entered into a state of dormancy at high temperature are assessed here by a recovery experiment. Furthermore, the contribution of covering layers on thermo-inhibition is analyzed here, including the way they work. This has been realized by the structural observation and via the determination of the abscisic acid (ABA) content. The results show that seeds germinate to a high percentage (approximately 90%) at temperatures of 15 or 20 °C, with or without light, whereas higher temperatures of 25 or 30 °C impeded radicle protrusion and resulted in the germination percentage decreasing sharply (within 5%). Inhibition at high temperatures was thoroughly reversed (bringing about approximately 80% germination) by placing the ungerminated seeds in favorable temperatures and incubating them for an additional 30 days. Dry cold storage did little to reduce the temperature request for germination. Embryo coverings, especially the nucellar membrane, and ABA levels both had a dominant role in seed germination regulation in response to temperature. Under favorable temperature conditions, the levels of ABA significantly decreased. Germination occurred when the levels dropped to a threshold of 15 ng/g (FW (Fresh Weight)). Incubation at a high temperature (25 °C) greatly increased ABA levels and caused the inhibition of radicle protrusion. Full article

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

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10 pages, 3310 KiB

Open AccessEditor’s ChoiceArticle

Effects of Wood Moisture Content and the Level of Acetylation on Brown Rot Decay

by Samuel L. Zelinka, Grant T. Kirker, Amy B. Bishell and Samuel V. Glass

Forests 2020, 11(3), 299; https://doi.org/10.3390/f11030299 - 07 Mar 2020

Cited by 19 | Viewed by 3083

Abstract

Acetylation is one of the most common types of wood modification and is commercially available throughout the world. Many studies have shown that acetylated wood is decay resistant at high levels of acetylation. Despite its widespread use, the mechanism by which acetylation prevents [...] Read more.

Acetylation is one of the most common types of wood modification and is commercially available throughout the world. Many studies have shown that acetylated wood is decay resistant at high levels of acetylation. Despite its widespread use, the mechanism by which acetylation prevents decay is still not fully understood. It is well known that at a given water activity, acetylation reduces the equilibrium moisture content of the wood cell wall. Furthermore, linear relationships have been found between the acetylation weight percent gain (WPG), wood moisture content, and the amount of mass loss in decay tests. This paper examines the relationships between wood moisture content and fungal growth in wood, with various levels of acetylation, by modifying the soil moisture content of standard soil block tests. The goal of the research is to determine if the reduction in fungal decay of acetylated wood is solely due to the reduction in moisture content or if there are additional antifungal effects of this chemical treatment. While a linear trend was observed between moisture content and mass loss caused by decay, it was not possible to separate out the effect of acetylation from fungal moisture generation. The data show significant deviations from previously proposed models for fungal moisture generation and suggest that these models cannot account for active moisture transport by the fungus. The study helps to advance our understanding of the role of moisture in the brown rot decay of modified wood. Full article

(This article belongs to the Special Issue Wood Protection and Preservation)

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13 pages, 1516 KiB

Open AccessEditor’s ChoiceArticle

The Impacts of Calamity Logging on the Development of Spruce Wood Prices in Czech Forestry

by Daniel Toth, Mansoor Maitah, Kamil Maitah and Veronika Jarolínová

Forests 2020, 11(3), 283; https://doi.org/10.3390/f11030283 - 29 Feb 2020

Cited by 59 | Viewed by 4000

Abstract

Currently, the decline in spruce wood prices is a serious problem for the forestry sector in the Czech Republic. We estimate that the fall in wood prices in European markets causes losses not only to the forestry companies producing, harvesting, and processing the [...] Read more.

Currently, the decline in spruce wood prices is a serious problem for the forestry sector in the Czech Republic. We estimate that the fall in wood prices in European markets causes losses not only to the forestry companies producing, harvesting, and processing the wood, but also to the workers in the sector. These losses are mainly caused by a combination of several natural factors: drought, climate change, and the effects of bark beetles. In particular, spruce bark beetles cause the greatest damage. Due to this bark beetle calamity, unplanned logging has increased. In 2019, these damages have culminated. Almost 100 million m³ of wood has been harvested over the last decade due to the bark beetle and more than half of this volume has been mined in the last four years. Therefore, the losses in the forestry sector are around EUR 1.12 billion. The aim of this study is an analysis of the relationship between the volume of incidental logging and the decline in the price of spruce wood. These results show the strong correlation between the measure of unplanned wood harvesting and the decrease in wood prices, as well as an estimate of price development if the upward trend of incidental mining continues. The average price of wood in the Czech Republic could thus reach a historical minimum of EUR 79.39 per m³ of spruce and category SM/JE II (spruce/fir). In addition, the decline in wood prices will be reflected in the management of forestry and timber businesses, including stagnant wages for forestry workers. The socio-economic impact of the bark beetle calamity is high and is most affected by the decline in spruce timber prices. Full article

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

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14 pages, 7108 KiB

Open AccessEditor’s ChoiceReview

Metrics of Growth Habit Derived from the 3D Tree Point Cloud Used for Species Determination—A New Approach in Botanical Taxonomy Tested on Dragon Tree Group Example

by Petr Vahalík, Karel Drápela, Andrea Procházková, Zdeněk Patočka, Marie Balková, Martin Šenfeldr, Klára Lengálová, Hana Kalivodová, Lucie Vaníčková, Lenka Ehrenbergerová, Samuel Lvončík and Petr Maděra

Forests 2020, 11(3), 272; https://doi.org/10.3390/f11030272 - 28 Feb 2020

Cited by 5 | Viewed by 2442

Abstract

Detailed, three-dimensional modeling of trees is a new approach in botanical taxonomy. Representations of individual trees are a prerequisite for accurate assessments of tree growth and morphological metronomy. This study tests the abilities of 3D modeling of trees to determine the various metrics [...] Read more.

Detailed, three-dimensional modeling of trees is a new approach in botanical taxonomy. Representations of individual trees are a prerequisite for accurate assessments of tree growth and morphological metronomy. This study tests the abilities of 3D modeling of trees to determine the various metrics of growth habit and compare morphological differences. The study included four species of the genus Dracaena: D. draco, D. cinnabari, D. ombet, and D. serrulata. Forty-nine 3D tree point clouds were created, and their morphological metrics were derived and compared. Our results indicate the possible application of 3D tree point clouds to dendrological taxonomy. Basic metrics of growth habit and coefficients derived from the 3D point clouds developed in the present study enable the statistical evaluation of differences among dragon tree species. Full article

(This article belongs to the Special Issue Dragon Trees - Tertiary Relicts in Current Reality)

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14 pages, 2467 KiB

Open AccessEditor’s ChoiceArticle

First Age-Estimation Model for Dracaena ombet and Dracaena draco subsp. caboverdeana

by Klára Lengálová, Hana Kalivodová, Hana Habrová, Petr Maděra, Berihu Tesfamariam and Martin Šenfeldr

Forests 2020, 11(3), 264; https://doi.org/10.3390/f11030264 - 27 Feb 2020

Cited by 11 | Viewed by 3290

Abstract

Research Highlights: The first model for crown age estimation was developed for Dracaena ombet Heuglin ex Kotschy and Peyr. and D. draco subsp. caboverdeana Marrero Rodr. and R. Almeida. Background and Objectives: Dracaena species are monocotyledon trees without annual tree rings. Most arborescent [...] Read more.

Research Highlights: The first model for crown age estimation was developed for Dracaena ombet Heuglin ex Kotschy and Peyr. and D. draco subsp. caboverdeana Marrero Rodr. and R. Almeida. Background and Objectives: Dracaena species are monocotyledon trees without annual tree rings. Most arborescent dragon tree species are endangered; thus, it is important to determine the age structures of these populations for proper conservation management strategies, and for modelling of population trends. For these reasons, it is necessary to develop a methodology of crown age estimation. Materials and Methods: Field data were collected in the Desa’a Forest (Ethiopia) and in Santo Antão (Cape Verde Islands). Trees within each age class, as expressed by the number of branch orders, were measured. The diameter at breast height, tree height, stem height, number of branch orders, number of all leaf rosettes and number of flowering leaf rosettes within the crown were recorded for each sampled tree. The flowering probabilities were counted as input data for the model used. Results: The duration of the interval between flowering events was 5.23 years for D. ombet and 4.94 years for D. draco subsp. caboverdeana. The crown of the oldest tree of D. ombet with 18 branch orders was estimated to be 94.2 years old, and the crown of the oldest tree of D. draco subsp. caboverdeana with 22 branch orders was estimated to be 108.6 years old. Full article

(This article belongs to the Special Issue Dragon Trees - Tertiary Relicts in Current Reality)

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20 pages, 3017 KiB

Open AccessEditor’s ChoiceArticle

Seed Networks for Upscaling Forest Landscape Restoration: Is It Possible to Expand Native Plant Sources in Brazil?

by Danilo I. de Urzedo, Fatima C.M. Piña-Rodrigues, Rafael Feltran-Barbieri, Rodrigo G.P. Junqueira and Robert Fisher

Forests 2020, 11(3), 259; https://doi.org/10.3390/f11030259 - 27 Feb 2020

Cited by 22 | Viewed by 8763

Abstract

In this paper, we explore how diverse community networks in Brazil have locally advanced seed production and institutional systems to enhance a restoration economy. By focusing on the experiences of the six major native seed suppliers in Amazonia, the Cerrado, and the Atlantic [...] Read more.

In this paper, we explore how diverse community networks in Brazil have locally advanced seed production and institutional systems to enhance a restoration economy. By focusing on the experiences of the six major native seed suppliers in Amazonia, the Cerrado, and the Atlantic Forest, we estimate the capacity to scale-up community-based systems to meet a large-scale restoration target as a rural development strategy. Over one decade, 1016 collectors traded 416.91 tonnes of native seeds representing, on average, 31.41 kilos yearly and USD 256.5 as household income. Based on this well documented empirical evidence, we estimate that Brazil’s restoration goal would require from 3.6 to 15.6 thousand tonnes of native seeds depending on the share of each restoration method adopted with potential work opportunities for 13.2 to 57.1 thousand collectors yearly and total income from USD 34 to 146 million. We argue that community networks represent feasible arrangements for increasing the availability of plant material sources which provide high socio-economic benefits. For scaling up native seed sources, we suggest the following key strategies: (i) government incentives and subsidies; (ii) enforcement of ecosystem restoration; (iii) community participation; (iv) adaptation of the seed regulations; (v) technological development; and (vi) seed market diversification. Full article

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

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34 pages, 3222 KiB

Open AccessEditor’s ChoiceReview

What We Know and What We Do Not Know about Dragon Trees?

by Petr Maděra, Alan Forrest, Pavel Hanáček, Petr Vahalík, Roman Gebauer, Roman Plichta, Radek Jupa, Julian Jansen Van Rensburg, Miranda Morris, Nadezhda Nadezhdina, Lucie Vaníčková, Joanna Jura-Morawiec, Justyna Wiland-Szymańska, Hana Kalivodová, Klára Lengálová, Martin Rejžek and Hana Habrová

Forests 2020, 11(2), 236; https://doi.org/10.3390/f11020236 - 21 Feb 2020

Cited by 34 | Viewed by 9876

Abstract

This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of [...] Read more.

This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species. Full article

(This article belongs to the Special Issue Dragon Trees - Tertiary Relicts in Current Reality)

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16 pages, 4512 KiB

Open AccessEditor’s ChoiceArticle

Comparing Individual Tree Height Information Derived from Field Surveys, LiDAR and UAV-DAP for High-Value Timber Species in Northern Japan

by Kyaw Thu Moe, Toshiaki Owari, Naoyuki Furuya and Takuya Hiroshima

Forests 2020, 11(2), 223; https://doi.org/10.3390/f11020223 - 15 Feb 2020

Cited by 60 | Viewed by 7807

Abstract

High-value timber species such as monarch birch (Betula maximowicziana Regel), castor aralia (Kalopanax septemlobus (Thunb.) Koidz), and Japanese oak (Quercus crispula Blume) play important ecological and economic roles in forest management in the cool temperate mixed forests in northern Japan. [...] Read more.

High-value timber species such as monarch birch (Betula maximowicziana Regel), castor aralia (Kalopanax septemlobus (Thunb.) Koidz), and Japanese oak (Quercus crispula Blume) play important ecological and economic roles in forest management in the cool temperate mixed forests in northern Japan. The accurate measurement of their tree height is necessary for both practical management and scientific reasons such as estimation of biomass and site index. In this study, we investigated the similarity of individual tree heights derived from conventional field survey, digital aerial photographs derived from unmanned aerial vehicle (UAV-DAP) data and light detection and ranging (LiDAR) data. We aimed to assess the applicability of UAV-DAP in obtaining individual tree height information for large-sized high-value broadleaf species. The spatial position, tree height, and diameter at breast height (DBH) were measured in the field for 178 trees of high-value broadleaf species. In addition, we manually derived individual tree height information from UAV-DAP and LiDAR data with the aid of spatial position data and high resolution orthophotographs. Tree heights from three different sources were cross-compared statistically through paired sample t-test, correlation coefficient, and height-diameter model. We found that UAV-DAP derived tree heights were highly correlated with LiDAR tree height and field measured tree height. The performance of individual tree height measurement using traditional field survey is likely to be influenced by individual species. Overall mean height difference between LiDAR and UAV-DAP derived tree height indicates that UAV-DAP could underestimate individual tree height for target high-value timber species. The height-diameter models revealed that tree height derived from LiDAR and UAV-DAP could be better explained by DBH with lower prediction errors than field measured tree height. We confirmed the applicability of UAV-DAP data for obtaining the individual tree height of large-size high-value broadleaf species with comparable accuracy to LiDAR and field survey. The result of this study will be useful for the species-specific forest management of economically high-value timber species. Full article

(This article belongs to the Special Issue Forest Resources Assessments: Mensuration, Inventory and Planning)

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20 pages, 2707 KiB

Open AccessEditor’s ChoiceArticle

Global Warming Mitigating Role of Wood Products from Washington State’s Private Forests

by Indroneil Ganguly, Francesca Pierobon and Edie Sonne Hall

Forests 2020, 11(2), 194; https://doi.org/10.3390/f11020194 - 10 Feb 2020

Cited by 15 | Viewed by 8618

Abstract

Similar to standing trees in the forests, wood products play an important role in enhancing the global sequestered carbon pool, by retaining the atmospheric carbon in a sequestered form for the duration of the functional life of the wood products. This study uses [...] Read more.

Similar to standing trees in the forests, wood products play an important role in enhancing the global sequestered carbon pool, by retaining the atmospheric carbon in a sequestered form for the duration of the functional life of the wood products. This study uses a temporal radiative forcing analysis along with the functional half-life of different wood products to evaluate the impacts of wood products on global warming, including carbon storage and life cycle greenhouse gas production/extraction emissions. The methodology is applied to Washington State’s aboveground biomass and timber harvest data, and to the State’s comprehensive wood products mix. A moderate harvest rate simulation within Washington Biomass Calculator is used to estimate state harvest level, and statewide wood products manufacturing data is used for developing wood product mix estimates. Using this method, we estimate that the temporal carbon storage leads to a global warming mitigation benefit equivalent to 4.3 million tCO_2eq. Even after factoring in the greenhouse gas emissions associated with the harvest operations and wood products manufacturing processes, within the temporal model, the results show a net beneficial impact of approximately 1.7 million tCO_2eq, on an annual basis. It can further be noted that Washington State’s annual biomass growth in its private forests exceeds its annual harvest, by a significant margin. This net yearly accumulation of biomass in the State’s private forests leads to additional global warming mitigation benefits equivalent to 7.4 million tCO_2eq. Based on these results, we conclude that Washington’s private forestry industry is a net global warming mitigator for the State, equivalent to 12% of the State’s greenhouse gas emissions in 2015. Full article

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

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15 pages, 767 KiB

Open AccessEditor’s ChoiceArticle

The Structural Gravity Model and Its Implications on Global Forest Product Trade

by Christian Morland, Franziska Schier and Holger Weimar

Forests 2020, 11(2), 178; https://doi.org/10.3390/f11020178 - 05 Feb 2020

Cited by 17 | Viewed by 4634

Abstract

The gravity model of trade is one of the most common approaches in modern econometrics. In its basic form, the model assumes that income and distance between two partners most likely play a major role in the occurrence of trade. Despite the long [...] Read more.

The gravity model of trade is one of the most common approaches in modern econometrics. In its basic form, the model assumes that income and distance between two partners most likely play a major role in the occurrence of trade. Despite the long history of the gravity model and its high, universal explanatory potential, its application for the forest sector is not broad and refers only to the traditional definition of the gravity approach. However, this traditional approach is not able to explain all aspects of trade at a disaggregated sector level. Consequently, the present study aims to close this research gap and reveal influencing factors for the appearance and the intensity of forest product trade by applying the structural gravity approach. This is done via linear and non-linear estimation methods for the forest sector on the whole and for thirteen forest products in detail. Three major results were found: first, the traditional gravity approach overestimates the impact of the overall income on forest sector trade. Second, the appearance of wood market trade is not always influenced by the same factors as the quantity traded. Third, with increasing processing level, determinants of forest product trade seem to be influenced by different factors. Full article

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

16 pages, 4055 KiB

Open AccessEditor’s ChoiceArticle

Deforestation and Connectivity among Protected Areas of Tanzania

by Belachew Gizachew, Jonathan Rizzi, Deo D. Shirima and Eliakimu Zahabu

Forests 2020, 11(2), 170; https://doi.org/10.3390/f11020170 - 04 Feb 2020

Cited by 20 | Viewed by 6406

Abstract

Protected Areas (PAs) in Tanzania had been established originally for the goal of habitat, landscape and biodiversity conservation. However, human activities such as agricultural expansion and wood harvesting pose challenges to the conservation objectives. We monitored a decade of deforestation within 708 PAs [...] Read more.

Protected Areas (PAs) in Tanzania had been established originally for the goal of habitat, landscape and biodiversity conservation. However, human activities such as agricultural expansion and wood harvesting pose challenges to the conservation objectives. We monitored a decade of deforestation within 708 PAs and their unprotected buffer areas, analyzed deforestation by PA management regimes, and assessed connectivity among PAs. Data came from a Landsat based wall-to-wall forest to non-forest change map for the period 2002–2013, developed for the definition of Tanzania’s National Forest Reference Emissions Level (FREL). Deforestation data were extracted in a series of concentric bands that allow pairwise comparison and correlation analysis between the inside of PAs and the external buffer areas. Half of the PAs exhibit either no deforestation or significantly less deforestation than the unprotected buffer areas. A small proportion (10%; n = 71) are responsible for more than 90% of the total deforestation; but these few PAs represent more than 75% of the total area under protection. While about half of the PAs are connected to one or more other PAs, the remaining half, most of which are Forest Reserves, are isolated. Furthermore, deforestation inside isolated PAs is significantly correlated with deforestation in the unprotected buffer areas, suggesting pressure from land use outside PAs. Management regimes varied in reducing deforestation inside PA territories, but differences in protection status within a management regime are also large. Deforestation as percentages of land area and forested areas of PAs was largest for Forest Reserves and Game Controlled areas, while most National Parks, Nature Reserves and Forest Plantations generally retained large proportions of their forest cover. Areas of immediate management concern include the few PAs with a disproportionately large contribution to the total deforestation, and the sizeable number of PAs being isolated. Future protection should account for landscapes outside protected areas, engage local communities and establish new PAs or corridors such as village-managed forest areas. Full article

(This article belongs to the Special Issue Protected Areas in Forest Conservation: Challenges and Opportunities)

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19 pages, 3360 KiB

Open AccessEditor’s ChoiceArticle

New Values of Non-Wood Forest Products

by Gerhard Weiss, Marla R. Emery, Giulia Corradini and Ivana Živojinović

Forests 2020, 11(2), 165; https://doi.org/10.3390/f11020165 - 31 Jan 2020

Cited by 45 | Viewed by 5967

Abstract

The role of non-wood forest products (NWFPs) in industrialised country economies has declined in the past, but they are generating renewed interest as business opportunities. In a forest-based bio-economy frame, NWFPs can contribute to human nutrition, renewable materials, and cultural and experiential services, [...] Read more.

The role of non-wood forest products (NWFPs) in industrialised country economies has declined in the past, but they are generating renewed interest as business opportunities. In a forest-based bio-economy frame, NWFPs can contribute to human nutrition, renewable materials, and cultural and experiential services, as well as create job and income opportunities in rural areas. Applying a service-dominant logic (SDL) approach to analysis of NWFPs, this article aimed to understand how new goods and services are co-created through networks of public and private actors in specific institutional, social, and cultural contexts. This focus sheds light on the experiences associated with NWFP harvest and use, revealing a fulsome suite of values and economic opportunities that include but are greater than the physical goods themselves. Turning the SDL lens on in-depth case studies from Europe and North America, we show dimensions of forest products that go beyond commercial values but are, at the same time, constituent of commercial activities. SDL provides a new view on customer relations, service provision to businesses, and policy measures for innovation support for non-wood forest products. Full article

(This article belongs to the Special Issue Foresight for Forest Bioeconomy)

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17 pages, 2600 KiB

Open AccessEditor’s ChoiceConcept Paper

From Dendrochronology to Allometry

by Franco Biondi

Forests 2020, 11(2), 146; https://doi.org/10.3390/f11020146 - 27 Jan 2020

Cited by 10 | Viewed by 6666

Abstract

The contribution of tree-ring analysis to other fields of scientific inquiry with overlapping interests, such as forestry and plant population biology, is often hampered by the different parameters and methods that are used for measuring growth. Here I present relatively simple graphical, numerical, [...] Read more.

The contribution of tree-ring analysis to other fields of scientific inquiry with overlapping interests, such as forestry and plant population biology, is often hampered by the different parameters and methods that are used for measuring growth. Here I present relatively simple graphical, numerical, and mathematical considerations aimed at bridging these fields, highlighting the value of crossdating. Lack of temporal control prevents accurate identification of factors that drive wood formation, thus crossdating becomes crucial for any type of tree growth study at inter-annual and longer time scales. In particular, exactly dated tree rings, and their measurements, are crucial contributors to the testing and betterment of allometric relationships. Full article

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

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28 pages, 14559 KiB

Open AccessEditor’s ChoiceArticle

Estimating Coarse Woody Debris Volume Using Image Analysis and Multispectral LiDAR

by Gustavo Lopes Queiroz, Gregory J. McDermid, Julia Linke, Christopher Hopkinson and Jahan Kariyeva

Forests 2020, 11(2), 141; https://doi.org/10.3390/f11020141 - 25 Jan 2020

Cited by 14 | Viewed by 5018

Abstract

Coarse woody debris (CWD, parts of dead trees) is an important factor in forest management, given its roles in promoting local biodiversity and unique microhabitats, as well as providing carbon storage and fire fuel. However, parties interested in monitoring CWD abundance lack accurate [...] Read more.

Coarse woody debris (CWD, parts of dead trees) is an important factor in forest management, given its roles in promoting local biodiversity and unique microhabitats, as well as providing carbon storage and fire fuel. However, parties interested in monitoring CWD abundance lack accurate methods to measure CWD accurately and extensively. Here, we demonstrate a novel strategy for mapping CWD volume (m³) across a 4300-hectare study area in the boreal forest of Alberta, Canada using optical imagery and an infra-canopy vegetation-index layer derived from multispectral aerial LiDAR. Our models predicted CWD volume with a coefficient of determination (R2) value of 0.62 compared to field data, and a root-mean square error (RMSE) of 0.224 m³/100 m². Models using multispectral LiDAR data in addition to image-analysis data performed with up to 12% lower RMSE than models using exclusively image-analysis layers. Site managers and researchers requiring reliable and comprehensive maps of CWD volume may benefit from the presented workflow, which aims to streamline the process of CWD measurement. As multispectral LiDAR radiometric calibration routines are developed and standardized, we expect future studies to benefit increasingly more from such products for CWD detection underneath canopy cover. Full article

(This article belongs to the Special Issue Forest Resources Assessments: Mensuration, Inventory and Planning)

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13 pages, 1910 KiB

Open AccessEditor’s ChoiceArticle

DBH Distributions in America’s Urban Forests—An Overview of Structural Diversity

by Justin Morgenroth, David J. Nowak and Andrew K. Koeser

Forests 2020, 11(2), 135; https://doi.org/10.3390/f11020135 - 23 Jan 2020

Cited by 22 | Viewed by 4974

Abstract

Background and Objectives: The structural diversity of an urban forest affects ecosystem service provision, and can inform management, planning, as well as policy. Trunk diameter at breast height (DBH) is amongst the most common measures of tree structure due to its ease of [...] Read more.

Background and Objectives: The structural diversity of an urban forest affects ecosystem service provision, and can inform management, planning, as well as policy. Trunk diameter at breast height (DBH) is amongst the most common measures of tree structure due to its ease of measurement and strong relationships with other structural and non-structural urban forest characteristics. Materials and Methods: In this study, the DBH distributions of urban forests are summarised for 38 American cities with a combined population of over 30 million people and a range of geographic, climatic, and demographic conditions. The Anderson–Darling (AD) test was used to test the hypothesis that all DBH distributions came from a common population. Moreover, structural diversity was compared using the Shannon–Wiener index. Results: The AD test results failed to identify any statistically significant differences in DBH distributions. However, qualitatively, the DBH distributions have two primary forms, which have important functional, management, and planning implications. The vast majority of cities have an exponentially inverse-proportional distribution, such that the proportion of trees in each successively larger DBH class decreases exponentially. The Shannon–Wiener index indicates an uneven DBH distribution in the cities with an exponentially inverse-proportional diameter distribution; these cities are dominated by trees in the smallest diameter class. Potential explanations for a large proportion of trees in the smallest diameter classes include a large number of small, naturally regenerating trees; a preference for smaller trees in urban areas; or a recent increase in tree planting efforts. Conclusions: Despite no statistical differences in DBH distributions for the 38 study cities, the functional, management, and planning implications will differ considerably. Full article

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

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15 pages, 2325 KiB

Open AccessEditor’s ChoiceArticle

Strategies for Modeling Regeneration Density in Relation to Distance from Adult Trees

by Daniel Moreno-Fernández, Alicia Ledo, Isabel Cañellas and Fernando Montes

Forests 2020, 11(1), 120; https://doi.org/10.3390/f11010120 - 19 Jan 2020

Cited by 4 | Viewed by 3056

Abstract

Research Highlights: We proposed new methodologies for the spatial analysis of regeneration processes and compared with existing approaches. Background and Objectives: Identifying the spatial relationship between adult trees and new cohorts is fundamental to understanding the dynamics of regeneration and therefore helps us [...] Read more.

Research Highlights: We proposed new methodologies for the spatial analysis of regeneration processes and compared with existing approaches. Background and Objectives: Identifying the spatial relationship between adult trees and new cohorts is fundamental to understanding the dynamics of regeneration and therefore helps us to optimize the stand density and natural regeneration when undertaking regeneration fellings. Most of the statistical approaches analyzing the spatial dependence between adult trees and new individuals (seedlings or saplings) require a complete census and mapping of all individuals. However, approaches considering individuals grouped into sampling points or subplots (i.e., density data) are limited. In this study, we reviewed and compared approaches (intertype point pattern analyses and a generalized additive model) to describe the spatial relationship between adult trees and density regeneration in a Pinus sylvestris L. monospecific stand in Spain. We also proposed a new approach (intertype mark variance function) to disentangle the effect of the tree-size on sapling density and the effect of the spatial pattern. Materials and Methods: To this end, we used a half-hectare plot in which all the individuals of P. sylvestris have been mapped and measured. Results: Our results indicated that sapling distribution was related to distance from the adult trees, thus displaying distance-dependence patterns, but it was not related to the size of the adult trees. The intertype mark correlation function was an useful tool to distinguish the effect of the marks (sapling density and tree size) from the effect of the spatial pattern of the classes (trees cohorts in our case). Conclusions: The largest number of saplings was found with increased distance between adult trees (>11 m), and the generalized additive model may be useful to explain spatial relationships between adult trees and regenerating cohorts when other measured biotic variables (e.g., soil stoniness, etc.) and repeated measurements are available. Full article

(This article belongs to the Special Issue Silviculture for Restoration and Regeneration)

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17 pages, 1942 KiB

Open AccessEditor’s ChoiceArticle

Interregional Crown Width Models for Individual Trees Growing in Pure and Mixed Stands in Austria

by Rafael Buchacher and Thomas Ledermann

Forests 2020, 11(1), 114; https://doi.org/10.3390/f11010114 - 16 Jan 2020

Cited by 18 | Viewed by 3267

Abstract

Crown width is a functional trait that is commonly used to improve the estimation of above-ground biomass of forests and is often included as a predictor variable in forest growth models. Most of the existing crown width models reflect the relationship between crown [...] Read more.

Crown width is a functional trait that is commonly used to improve the estimation of above-ground biomass of forests and is often included as a predictor variable in forest growth models. Most of the existing crown width models reflect the relationship between crown width, tree size and competition variables, but do not consider the effect of species mixture. In this study, we developed crown width models for individual-tree of the major tree species growing in Austria. Because these models should be applicable for mixed and pure stands and should also take into account the characteristics of different sites, the relationship between crown width, site variables and species composition was investigated. For that purpose, we used data from a sub-sample of the Austrian National Forest Inventory, which comprises crown width measurements of about 8900 trees from 1508 sample plots. Because of the hierarchical structure of the data set (i.e., trees nested within the plot) which destroys the independencies between observations, linear mixed-effects models were used. The species composition of the stand was included via the species-specific relative proportions of basal area. To describe the interregional variability of crown width, dummy variables were introduced, which account for region-specific differences. Site characteristics were incorporated through the altitude, slope and aspect of the site. For Norway spruce, silver fir, Scots pine, European larch, European beech, oak species and ash/maple species it was possible to develop crown width models, which reflect the effects of site characteristics and species composition of the stand. The crown widths of shade-tolerant species reacted mainly positively to admixture, whereas light-demanding species reacted with decreasing crown widths. Coniferous species were not as strongly affected by mixture as broadleaf species. Full article

(This article belongs to the Special Issue Modelling Mixing Effects in Forest Stands)

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13 pages, 1894 KiB

Open AccessEditor’s ChoiceArticle

Chemical Fingerprinting of Wood Sampled along a Pith-to-Bark Gradient for Individual Comparison and Provenance Identification

by Victor Deklerck, Cady A. Lancaster, Joris Van Acker, Edgard O. Espinoza, Jan Van den Bulcke and Hans Beeckman

Forests 2020, 11(1), 107; https://doi.org/10.3390/f11010107 - 15 Jan 2020

Cited by 12 | Viewed by 3612

Abstract

Background and Objectives: The origin of traded timber is one of the main questions in the enforcement of regulations to combat the illegal timber trade. Substantial efforts are still needed to develop techniques that can determine the exact geographical provenance of timber and [...] Read more.

Background and Objectives: The origin of traded timber is one of the main questions in the enforcement of regulations to combat the illegal timber trade. Substantial efforts are still needed to develop techniques that can determine the exact geographical provenance of timber and this is vital to counteract the destructive effects of illegal logging, ranging from economical loss to habitat destruction. The potential of chemical fingerprints from pith-to-bark growth rings for individual comparison and geographical provenance determination is explored. Materials and Methods: A wood sliver was sampled per growth ring from four stem disks from four individuals of Pericopsis elata (Democratic Republic of the Congo) and from 14 stem disks from 14 individuals of Terminalia superba (Côte d’Ivoire and Democratic Republic of the Congo). Chemical fingerprints were obtained by analyzing these wood slivers with Direct Analysis in Real Time Time-Of-Flight Mass Spectrometry (DART TOFMS). Results: Individual distinction for both species was achieved but the accuracy was dependent on the dataset size and number of individuals included. As this is still experimental, we can only speak of individual comparison and not individual distinction at this point. The prediction accuracy for the country of origin increases with increasing sample number and a random sample can be placed in the correct country. When a complete disk is removed from the training dataset, its rings (samples) are correctly attributed to the country with an accuracy ranging from 43% to 100%. Relative abundances of ions appear to contribute more to differentiation compared to frequency differences. Conclusions: DART TOFMS shows potential for geographical provenancing but is still experimental for individual distinction; more research is needed to make this an established method. Sampling campaigns should focus on sampling tree cores from pith-to-bark, paving the way towards a chemical fingerprint database for species provenance. Full article

(This article belongs to the Special Issue Wood Science and Tropical Forest Ecology)

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19 pages, 2006 KiB

Open AccessEditor’s ChoiceArticle

Forecasting Forest Areas in Myanmar Based on Socioeconomic Factors

by Tetsuya Michinaka, Ei Ei Swe Hlaing, Thaung Naing Oo, Myat Su Mon and Tamotsu Sato

Forests 2020, 11(1), 100; https://doi.org/10.3390/f11010100 - 13 Jan 2020

Cited by 5 | Viewed by 4268

Abstract

National circumstances should be considered in establishing and adjusting forest reference emission levels (FRELs/FRLs) under the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD+ Programme). Myanmar, one of the world’s least developed countries may face accelerating deforestation under an [...] Read more.

National circumstances should be considered in establishing and adjusting forest reference emission levels (FRELs/FRLs) under the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD+ Programme). Myanmar, one of the world’s least developed countries may face accelerating deforestation under an open and democratic political system that desires rapid economic development. This research analyzes the impacts of population growth and economic development on forest areas in Myanmar by using panel data analysis, an econometrics approach based on panel data of forest areas, population, and gross domestic product (GDP) by states and regions in 2005, 2010, and 2015. This research revealed that per capita GDP and population density gave statistically significant negative impacts on forest areas. Using the regression model obtained above, medium population growth projections, and three GDP development scenarios, annual forest areas from 2016 to 2020 were forecast. The forecasting results showed possible higher deforestation under higher economic development. Finally, this research showed the necessity of adjusting the current average deforestation for RELs in the REDD+ scheme in Myanmar and the direction in which the adjustment should go. Full article

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

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30 pages, 12275 KiB

Open AccessEditor’s ChoiceArticle

A Survey in Natural Forest Ecosystems of Vietnam Reveals High Diversity of both New and Described Phytophthora Taxa including P. ramorum

by Thomas Jung, Bruno Scanu, Clive M. Brasier, Joan Webber, Ivan Milenković, Tamara Corcobado, Michal Tomšovský, Matěj Pánek, József Bakonyi, Cristiana Maia, Aneta Bačová, Milica Raco, Helen Rees, Ana Pérez-Sierra and Marília Horta Jung

Forests 2020, 11(1), 93; https://doi.org/10.3390/f11010093 - 12 Jan 2020

Cited by 56 | Viewed by 7411

Abstract

In 2016 and 2017, surveys of Phytophthora diversity were performed in 25 natural and semi-natural forest stands and 16 rivers in temperate and subtropical montane and tropical lowland regions of Vietnam. Using baiting assays from soil samples and rivers and direct isolations from [...] Read more.

In 2016 and 2017, surveys of Phytophthora diversity were performed in 25 natural and semi-natural forest stands and 16 rivers in temperate and subtropical montane and tropical lowland regions of Vietnam. Using baiting assays from soil samples and rivers and direct isolations from naturally fallen leaves, 13 described species, five informally designated taxa and 21 previously unknown taxa of Phytophthora were isolated from 58 of the 91 soil samples (63.7%) taken from the rhizosphere of 52 of the 64 woody plant species sampled (81.3%) in 20 forest stands (83.7%), and from all rivers: P. capensis, P. citricola VII, VIII, IX, X and XI, P. sp. botryosa-like 2, P. sp. meadii-like 1 and 2, P. sp. tropicalis-like 2 and P. sp. multivesiculata-like 1 from Phytophthora major phylogenetic Clade 2; P. castaneae and P. heveae from Clade 5; P. chlamydospora, P. gregata, P. sp. bitahaiensis-like and P. sp. sylvatica-like 1, 2 and 3 from Clade 6; P. cinnamomi (Pc), P. parvispora, P. attenuata, P. sp. attenuata-like 1, 2 and 3 and P. ×heterohybrida from Clade 7; P. drechsleri, P. pseudocryptogea, P. ramorum (Pr) and P. sp. kelmania from Clade 8, P. macrochlamydospora, P. sp. ×insolita-like, P. sp. ×kunnunara-like, P. sp. ×virginiana-like s.l. and three new taxa, P. sp. quininea-like, P. sp. ×Grenada 3-like and P. sp. ×Peru 4-like, from Clade 9; and P. sp. gallica-like 1 and 2 from Clade 10. The A1 and A2 mating types of both Pc and Pr co-occurred. The A2 mating type of Pc was associated with severe dieback of montane forests in northern Vietnam. Most other Phytophthora species, including Pr, were not associated with obvious disease symptoms. It is concluded that (1) Vietnam is within the center of origin of most Phytophthora taxa found including Pc and Pr, and (2) Phytophthora clades 2, 5, 6, 7, 8, 9, and 10 are native to Indochina. Full article

(This article belongs to the Special Issue Phytophthora Infestations in Forest Ecosystems)

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25 pages, 4542 KiB

Open AccessEditor’s ChoiceArticle

Gap Structure and Regeneration in the Mixed Old-Growth Forests of National Nature Reserve Sitno, Slovakia

by Peter Jaloviar, Denisa Sedmáková, Ján Pittner, Lucia Jarčušková Danková, Stanislav Kucbel, Robert Sedmák and Milan Saniga

Forests 2020, 11(1), 81; https://doi.org/10.3390/f11010081 - 09 Jan 2020

Cited by 23 | Viewed by 3881

Abstract

Forest management mimicking natural processes represents an approach to maintain mixed, uneven-aged stands at small spatial scales. The reliance on natural processes, especially on natural regeneration leads to the use of gap-based regeneration as a fundamental silvicultural technique. As a baseline for such [...] Read more.

Forest management mimicking natural processes represents an approach to maintain mixed, uneven-aged stands at small spatial scales. The reliance on natural processes, especially on natural regeneration leads to the use of gap-based regeneration as a fundamental silvicultural technique. As a baseline for such management, we investigated mixed forest in unmanaged National Nature Reserve Sitno in the Western Carpathians, which harbours extraordinary diversity on a rather small scale. To quantify the impact of gaps on gap-filling processes and to assess the role they play in recently observed changes in tree species composition we established a large (2.5 ha) permanent research plot and surveyed the status of natural regeneration, forest structure, tree species composition, and disturbance regime. Our research highlights the long-term and contemporary difficulties in the establishment of Quercus petraea (Matt.) Liebl and Fagus sylvatica (L.). Based on the provided evidence, the native tree species diversity in one of the few preserved old-growth multi-species beech-oak forest remnants is not likely to persist, what could have many implications for future ecosystem functioning. Our results suggest that variation in gap size is an important factor contributing to composition of tree species composition of natural regeneration. The recent intermediate-scale disturbance pattern dominating the old-growth beech-oak forest is beneficial to canopy recruitment of species less shade-tolerant than Fagus sylvatica, as Acer pseudoplatanus (L.), Acer platanoides (L.), and Fraxinus excelsior (L.). We discuss possible factors behind observed shifts in tree species composition and limitations for application of gap dynamics to forest practice in managed beech-oak forest systems. Overall, results of this study may help to design silvicultural measures promoting mixed-species forests to deliver a range of desired ecosystem services. Full article

(This article belongs to the Special Issue Role of Gap Factors in Forest Tree Regeneration and Plant Communities)

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22 pages, 2241 KiB

Open AccessEditor’s ChoiceReview

Functional Role of Extrafloral Nectar in Boreal Forest Ecosystems under Climate Change

by Jarmo K. Holopainen, James D. Blande and Jouni Sorvari

Forests 2020, 11(1), 67; https://doi.org/10.3390/f11010067 - 06 Jan 2020

Cited by 6 | Viewed by 6460

Abstract

Carbohydrate-rich extrafloral nectar (EFN) is produced in nectaries on the leaves, stipules, and stems of plants and provides a significant energy source for ants and other plant mutualists outside of the flowering period. Our review of literature on EFN indicates that only a [...] Read more.

Carbohydrate-rich extrafloral nectar (EFN) is produced in nectaries on the leaves, stipules, and stems of plants and provides a significant energy source for ants and other plant mutualists outside of the flowering period. Our review of literature on EFN indicates that only a few forest plant species in cool boreal environments bear EFN-producing nectaries and that EFN production in many boreal and subarctic plant species is poorly studied. Boreal forest, the world’s largest land biome, is dominated by coniferous trees, which, like most gymnosperms, do not produce EFN. Notably, common deciduous tree species that can be dominant in boreal forest stands, such as Betula and Alnus species, do not produce EFN, while Prunus and Populus species are the most important EFN-producing tree species. EFN together with aphid honeydew is known to play a main role in shaping ant communities. Ants are considered to be keystone species in mixed and conifer-dominated boreal and mountain forests because they transfer a significant amount of carbon from the canopy to the soil. Our review suggests that in boreal forests aphid honeydew is a more important carbohydrate source for ants than in many warmer ecosystems and that EFN-bearing plant species might not have a competitive advantage against herbivores. However, this hypothesis needs to be tested in the future. Warming of northern ecosystems under climate change might drastically promote the invasion of many EFN-producing plants and the associated insect species that consume EFN as their major carbohydrate source. This may result in substantial changes in the diet preferences of ant communities, the preventative roles of ants against insect pest outbreaks, and the ecosystem services they provide. However, wood ants have adapted to using tree sap that leaks from bark cracks in spring, which may mitigate the effects of improved EFN availability. Full article

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

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12 pages, 717 KiB

Open AccessEditor’s ChoiceReview

Forest Climax Phenomenon: An Invariance of Scale

by Raimundas Petrokas

Forests 2020, 11(1), 56; https://doi.org/10.3390/f11010056 - 02 Jan 2020

Cited by 6 | Viewed by 3244

Abstract

We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen [...] Read more.

We can think of forests as multiscale multispecies networks, constantly evolving toward a climax or potential natural community—the successional process-pattern of natural regeneration that exhibits sensitivity to initial conditions. This is why I look into forest succession in light of the Red Queen hypothesis and focus on the key aspects of ecological self-organisation: dynamical criticality, evolvability and intransitivity. The idea of the review is that forest climax should be associated with habitat dynamics driven by a large continuum of ecologically equivalent time scales, so that the same ecological conclusions could be drawn statistically from any scale. A synthesis of the literature is undertaken in order to (1) present the framework for assessing habitat dynamics and (2) present the types of successional trajectories based on tree regeneration mode in forest gaps. In general, there are four types of successional trajectories within the process-pattern of forest regeneration that exhibits sensitivity to initial conditions: advance reproduction specialists, advance reproduction generalists, early reproduction generalists and early reproduction specialists. A successional trajectory is an expression of a fractal connectivity among certain patterns of natural regeneration in the multiscale multispecies networks of landscape habitats. Theoretically, the organically derived measures of pattern diversity, integrity and complexity, determined by the rates of recruitment, growth and mortality of forest tree species, are the means to test the efficacy of specific interventions to avert the disturbance-related decline in forest regeneration. That is of relevance to the emerging field of biocomplexity research. Full article

(This article belongs to the Special Issue Protection and Management of Species, Habitats, Ecosystems and Landscapes)

12 pages, 1296 KiB

Open AccessEditor’s ChoiceArticle

Corrosiveness of Thermally Modified Wood

by Samuel L. Zelinka, Leandro Passarini, Frederick J. Matt and Grant T. Kirker

Forests 2020, 11(1), 50; https://doi.org/10.3390/f11010050 - 31 Dec 2019

Cited by 7 | Viewed by 2961

Abstract

Thermally modified wood is becoming commercially available in North America for use in outdoor applications. While there have been many studies on how thermal modification affects the dimensional stability, water vapor sorption, and biodeterioration of wood, little is known about whether thermally modified [...] Read more.

Thermally modified wood is becoming commercially available in North America for use in outdoor applications. While there have been many studies on how thermal modification affects the dimensional stability, water vapor sorption, and biodeterioration of wood, little is known about whether thermally modified wood is corrosive to metal fasteners and hangers used to hold these members in place. As thermally modified wood is used in outdoor applications, it has the potential to become wet which may lead to corrosion of embedded fasteners. Here, we examine the corrosiveness of thermally modified ash and oak in an exposure test where stainless steel, hot-dip galvanized steel, and carbon steel nails are driven into wood and exposed to a nearly 100% relative humidity environment at 27 °C for one year. The corrosion rates were compared against control specimens of untreated and preservative-treated southern pine. Stainless steel fasteners did not corrode in any specimens regardless of the treatment. The thermal modification increased the corrosiveness of the ash and oak, however, an oil treatment that is commonly applied by the manufacturer to the wood after the heat treatment reduced the corrosiveness. The carbon steel fasteners exhibited higher corrosion rates in the thermally modified hardwoods than in the preservative-treated pine control. Corrosion rates of galvanized fasteners in the hardwoods were much lower than carbon steel fasteners. These data can be used to design for corrosion when building with thermally modified wood, and highlight differences between corrosion of metals embedded in wood products. Full article

(This article belongs to the Special Issue Wood Protection and Preservation)

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31 pages, 3565 KiB

Open AccessEditor’s ChoiceReview

Treeline Research—From the Roots of the Past to Present Time. A Review

by Friedrich-Karl Holtmeier and Gabriele Broll

Forests 2020, 11(1), 38; https://doi.org/10.3390/f11010038 - 26 Dec 2019

Cited by 41 | Viewed by 6202

Abstract

Elevational and polar treelines have been studied for more than two centuries. The aim of the present article is to highlight in retrospect the scope of treeline research, scientific approaches and hypotheses on treeline causation, its spatial structures and temporal change. Systematic treeline [...] Read more.

Elevational and polar treelines have been studied for more than two centuries. The aim of the present article is to highlight in retrospect the scope of treeline research, scientific approaches and hypotheses on treeline causation, its spatial structures and temporal change. Systematic treeline research dates back to the end of the 19th century. The abundance of global, regional, and local studies has provided a complex picture of the great variety and heterogeneity of both altitudinal and polar treelines. Modern treeline research started in the 1930s, with experimental field and laboratory studies on the trees’ physiological response to the treeline environment. During the following decades, researchers’ interest increasingly focused on the altitudinal and polar treeline dynamics to climate warming since the Little Ice Age. Since the 1970s interest in treeline dynamics again increased and has considerably intensified from the 1990s to today. At the same time, remote sensing techniques and GIS application have essentially supported previous analyses of treeline spatial patterns and temporal variation. Simultaneously, the modelling of treeline has been rapidly increasing, often related to the current treeline shift and and its implications for biodiversity, and the ecosystem function and services of high-elevation forests. It appears, that many seemingly ‘new ideas’ already originated many decades ago and just confirm what has been known for a long time. Suggestions for further research are outlined. Full article

(This article belongs to the Special Issue Alpine and Polar Treelines in a Changing Environment)

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13 pages, 2890 KiB

Open AccessEditor’s ChoiceArticle

Machine Learning Models with Quantitative Wood Anatomy Data Can Discriminate between Swietenia macrophylla and Swietenia mahagoni

by Tuo He, João Marco, Richard Soares, Yafang Yin and Alex C. Wiedenhoeft

Forests 2020, 11(1), 36; https://doi.org/10.3390/f11010036 - 25 Dec 2019

Cited by 24 | Viewed by 4317

Abstract

Illegal logging and associated trade aggravate the over-exploitation of Swietenia species, of which S. macrophylla King, S. mahagoni (L.) Jacq, and S. humilis Zucc. have been listed in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix Ⅱ. [...] Read more.

Illegal logging and associated trade aggravate the over-exploitation of Swietenia species, of which S. macrophylla King, S. mahagoni (L.) Jacq, and S. humilis Zucc. have been listed in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix Ⅱ. Implementation of CITES necessitates the development of efficient forensic tools to identify wood species accurately, and ideally ones readily deployable in wood anatomy laboratories across the world. Herein, a method using quantitative wood anatomy data in combination with machine learning models to discriminate between three Swietenia species is presented, in addition to a second model focusing only on the two historically more important species S. mahagoni and S. macrophylla. The intra- and inter-specific variations in nine quantitative wood anatomical characters were measured and calculated based on 278 wood specimens, and four machine learning classifiers—Decision Tree C5.0, Naïve Bayes (NB), Support Vector Machine (SVM), and Artificial Neural Network (ANN)—were used to discriminate between the species. Among these species, S. macrophylla exhibited the largest intraspecific variation, and all three species showed at least partly overlapping values for all nine characters. SVM performed the best of all the classifiers, with an overall accuracy of 91.4% and a per-species correct identification rate of 66.7%, 95.0%, and 80.0% for S. humilis, S. macrophylla, and S. mahagoni, respectively. The two-species model discriminated between S. macrophylla and S. mahagoni with accuracies of over 90.0% using SVM. These accuracies are lower than perfect forensic certainty but nonetheless demonstrate that quantitative wood anatomy data in combination with machine learning models can be applied as an efficient tool to discriminate anatomically between similar species in the wood anatomy laboratory. It is probable that a range of previously anatomically inseparable species may become identifiable by incorporating in-depth analysis of quantitative characters and appropriate statistical classifiers. Full article

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

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11 pages, 1547 KiB

Open AccessEditor’s ChoiceArticle

Multifunctional Forestry and Interaction with Site Quality

by Ing-Marie Gren and Franklin Amuakwa-Mensah

Forests 2020, 11(1), 29; https://doi.org/10.3390/f11010029 - 23 Dec 2019

Cited by 5 | Viewed by 2650

Abstract

Several studies have shown the economic value of various ecosystem services provided by the forest. However, the economic value of how site-specific ecological conditions interact with other functions provided by the forest, such as timber value and carbon sequestration, has been less studied. [...] Read more.

Several studies have shown the economic value of various ecosystem services provided by the forest. However, the economic value of how site-specific ecological conditions interact with other functions provided by the forest, such as timber value and carbon sequestration, has been less studied. As a result, this paper constructs a numerical discrete dynamic optimization model to estimate the economic value of site quality, taking into account its interaction with timber value and carbon sequestration, in Swedish forests. Analytical results show that the inclusion of the interaction of site quality with forest growth affects the optimal volume of harvest per year, compared to the case without consideration of site quality. The empirical results show that net present value, when considering timber values plus carbon sequestration and site quality interaction, is higher than the case where only timber and carbon sequestration were considered. However, the calculated net present value is sensitive to, in particular, the price of carbon sequestration and discount rate. Full article

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

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11 pages, 5623 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Preservative-Treated Wooden Poles Using Drilling-Resistance Measurements

by Evgenii Sharapov, Christian Brischke and Holger Militz

Forests 2020, 11(1), 20; https://doi.org/10.3390/f11010020 - 21 Dec 2019

Cited by 13 | Viewed by 3570

Abstract

An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles [...] Read more.

An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles that were industrially vacuum-pressure-impregnated with a copper-based preservative (Korasit KS-M) and untreated reference poles. Both types of poles were subject to 10.5 years of in-ground exposure. Wood moisture content (MC) was measured using a resistance-type moisture meter. MC varied between 15% and 60% in the radial and axial directions in both treated and untreated poles. A higher MC was detected in the underground, top, and outer (sapwood) parts of the poles. Typical drilling-resistance (DR) profiles of poles with internal defects were analyzed. Preservative treatment had a significant influence on wood durability in the underground part of the poles. Based on DR measurements, we found that untreated wood that was in contact with soil was severely degraded by insects and wood-destroying fungi. Conversely, treated wood generally showed no reduction in DR or feeding resistance (FR). DR profiling is a potential method for the in-situ or in vitro assessment and quality monitoring of preservative treatments and wood durability. The technological benefits of using drill bits with one major cutting edge, instead of standard drill bits with center-spiked tips and two major cutting edges, were not evident. A new graphical method was applied to present DR data and their spatial distribution in the poles. Future studies should focus on the impact of preservative treatments, thermal modification, and chemical modification on the DR and FR of wood. This may further elucidate the predictive value of DR and FR for wood properties. Full article

(This article belongs to the Special Issue Wood Protection and Preservation)

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19 pages, 3404 KiB

Open AccessEditor’s ChoiceArticle

Dynamics and Management of Rising Outbreak Spruce Budworm Populations

by Jacques Régnière, Barry J. Cooke, Ariane Béchard, Alain Dupont and Pierre Therrien

Forests 2019, 10(9), 748; https://doi.org/10.3390/f10090748 - 01 Sep 2019

Cited by 30 | Viewed by 3594

Abstract

Management of spruce budworm, Choristoneura fumiferana (Clem.), outbreak spread requires understanding the demographic processes occurring in low, but rising populations. For the first time, detailed observations were made in the early stages of outbreak development. We sampled populations over a three-year period in [...] Read more.

Management of spruce budworm, Choristoneura fumiferana (Clem.), outbreak spread requires understanding the demographic processes occurring in low, but rising populations. For the first time, detailed observations were made in the early stages of outbreak development. We sampled populations over a three-year period in both treated and untreated populations in the Lower St-Lawrence region of Quebec, Canada, and measured the density-dependence of survival and population growth rates, and the impact of natural enemies and insecticides. Insecticides tested were Bacillus thuringiensis (Berliner 1915) and tebufenozide. We recorded strong density-dependence of survival between early larval stages and adult emergence, explained largely by the variation of natural enemy impacts and overcrowding. We also observed inverse density-dependence of apparent fecundity: net immigration into lower-density populations and net emigration from the higher, linked to a threshold of ~25% defoliation. Because of high migration rates, none of the 2013 treatments reduced egg populations at the end of summer. However lower migration activity in 2014 allowed population growth to be reduced in treated plots. This evidence lends support to the conclusion that, for a budworm population to increase to outbreak density, it must be elevated via external perturbations, such as immigration, above a threshold density of ~4 larvae per branch tip (L₄). Once a population has increased beyond this threshold, it can continue growing and itself become a source of further spread by moth migration. These findings imply that populations can be brought down by insecticide applications to a density where mortality from natural enemies can keep the reduced population in check, barring subsequent immigration. While we recognize that other factors may occasionally cause a population to exceed the Allee threshold and reach outbreak level, the preponderance of immigration implies that if all potential sources of significant numbers of moths are reduced on a regional scale by insecticide applications, a widespread outbreak can be prevented, stopped or slowed down by reducing the supply of migrating moths. Full article

(This article belongs to the Special Issue Protection Strategy against Spruce Budworm)

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19 pages, 2787 KiB

Open AccessEditor’s ChoiceReview

Tropical Dry Forest Diversity, Climatic Response, and Resilience in a Changing Climate

by Kayla Stan and Arturo Sanchez-Azofeifa

Forests 2019, 10(5), 443; https://doi.org/10.3390/f10050443 - 23 May 2019

Cited by 56 | Viewed by 11204

Abstract

Central and South America tropical dry forest (TDF) is a water-limited biome with a high number of endemic species and numerous ecosystem services which has experienced a boom in research in the last decade. Although the number of case studies across these seasonal, [...] Read more.

Central and South America tropical dry forest (TDF) is a water-limited biome with a high number of endemic species and numerous ecosystem services which has experienced a boom in research in the last decade. Although the number of case studies across these seasonal, water-limited, tropical forests has increased, there has not been a comprehensive review to assess the physiological variability of this biome across the continent and assess how these forests respond to climatic variables. Additionally, understanding forest change and resilience under climatic variability, currently and in the future, is essential for assessing the future extent and health of forests in the future. Therefore, the objective of this paper is to provide a literature review on the variability of TDF diversity and structure across a latitudinal gradient and to assess how these components respond to differences in climatic variables across this geographic area. We first assess the current state of understanding of the structure, biomass, phenological cycles, and successional stages across the latitudinal gradient. We subsequently review the response of these five areas to differences in precipitation, temperature, and extreme weather events, such as droughts and hurricanes. We find that there is a range of adaptability to precipitation, with many areas exhibiting drought tolerance except under the most extreme circumstances, while being susceptible to damage from increased extreme precipitation events. Finally, we use this climatic response to provide a commentary on the projected resilience of TDFs under climatic changes, finding a likelihood of resilience under drying scenarios, although model projections do not agree on the magnitude or direction of precipitation change. This review of quantitative studies will provide more concrete details on the current diversity that encompasses the TDF, the natural climatic ranges under which this ecosystem can survive and thrive, and can help inform future forest management practices under climate change scenarios. Full article

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

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16 pages, 1617 KiB

Open AccessEditor’s ChoiceArticle

Measuring Livelihood Diversification and Forest Conservation Choices: Insights from Rural Cameroon

by Jude Ndzifon Kimengsi, Jürgen Pretzsch, Mukong Alfred Kechia and Symphorien Ongolo

Forests 2019, 10(2), 81; https://doi.org/10.3390/f10020081 - 22 Jan 2019

Cited by 23 | Viewed by 6064

Abstract

While forests’ contribution to rural livelihoods has been unearthed scientifically, the patterns, determinants and forest conservation policy implications of livelihood diversification still beg for more scientific and policy edification. This paper makes a contribution in this regard, using household data (N = [...] Read more.

While forests’ contribution to rural livelihoods has been unearthed scientifically, the patterns, determinants and forest conservation policy implications of livelihood diversification still beg for more scientific and policy edification. This paper makes a contribution in this regard, using household data (N = 200) from eight villages around the Kilum-Ijim Forest Landscape of Cameroon. The ordinary least square and the logit model are used to explore the determinants of livelihood diversification and the likelihood of forest dependence, respectively. The diversification patterns were analysed using a simple t-test, and the multinomial logit for conservation choices. We find that forest-related activities are a source of livelihood diversification for 63% of households, with non-timber forest products (NTFP) domestication (31%) and medicinal plant extraction (30%) being the most preferred. For non-forest activities, migration is the most preferred diversification strategy. Generally, households with favourable socio-economic status prefer non-forest to forest activities for livelihood diversification. The regression estimates indicate that older respondents are more likely to depend on the forest than the young, whereas males and individuals with at least some secondary education are less likely than their respective counterparts to rely on the forest. The results also suggest those who participated in training, educated household heads and older individuals are significantly more likely to choose high-valued diversification strategies. Concerning conservation activities, households with favourable socio-economic status are on average less likely to adopt NTFP domestication and more likely to adopt bee-keeping as a conservation choice. The results suggest the need for policy considerations to: (i) effectively integrate women in forest management processes, (ii) intensify trainings for conservation-friendly diversification approaches, (iii) regulate unclean energy use and (iv) encourage value chain improvement for conservation-friendly products. Full article

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

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