Forests

15 pages, 2430 KiB

Open AccessArticle

Chloroplast Haplotypes of Northern Red Oak (Quercus rubra L.) Stands in Germany Suggest Their Origin from Northeastern Canada

by Jeremias Götz, Konstantin V. Krutovsky, Ludger Leinemann, Markus Müller, Om P. Rajora and Oliver Gailing

Forests 2020, 11(9), 1025; https://doi.org/10.3390/f11091025 - 22 Sep 2020

Cited by 5 | Viewed by 2513

Abstract

Northern red oak (Quercus rubra L.) is one of the most important foreign tree species in Germany and considered as a major candidate for prospective sustainable forestry in the face of climate change. Therefore, Q. rubra was subject of many previous studies [...] Read more.

Northern red oak (Quercus rubra L.) is one of the most important foreign tree species in Germany and considered as a major candidate for prospective sustainable forestry in the face of climate change. Therefore, Q. rubra was subject of many previous studies on its growth traits and attempts to infer the origin of various populations of this species using nuclear and chloroplast DNA markers. However, the exact geographic origin of German red oak stands has still not been identified. Its native range widely extends over North America, and the species can tolerate a broad range of environmental conditions. We genotyped individual trees in 85 populations distributed in Germany and North America using five chloroplast microsatellite and three novel chloroplast CAPS markers, resulting in the identification of 29 haplotypes. The new marker set enabled the identification of several new red oak haplotypes with restricted geographic origin. Some very rare haplotypes helped us narrow down the origin of Q. rubra stands in Germany, especially some stands from North Rhine-Westphalia, to the northern part of the species’ natural distribution area including the Peninsula of Nova Scotia, where the most similar haplotype composition was observed, compared to distinct German stands. Full article

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23 pages, 10013 KiB

Open AccessArticle

Improving Fungal Decay Resistance of Less Durable Sapwood by Impregnation with Scots Pine Knotwood and Black Locust Heartwood Hydrophilic Extractives with Antifungal or Antioxidant Properties

by Viljem Vek, Angela Balzano, Ida Poljanšek, Miha Humar and Primož Oven

Forests 2020, 11(9), 1024; https://doi.org/10.3390/f11091024 - 22 Sep 2020

Cited by 21 | Viewed by 2771

Abstract

Research Highlights: The antifungal assay confirmed that knotwood extractives of Scots pine inhibit the growth of wood decay fungi. Heartwood extracts of black locust were found to be much stronger free radical scavengers than the extracts of Scots pine. The extracts were deposited [...] Read more.

Research Highlights: The antifungal assay confirmed that knotwood extractives of Scots pine inhibit the growth of wood decay fungi. Heartwood extracts of black locust were found to be much stronger free radical scavengers than the extracts of Scots pine. The extracts were deposited in the lumina and on the wall surface of cells in the impregnated sapwood. Impregnation of the sapwood blocks with Scots pine and black locust extracts reduced the fungal decay of wood. Objectives: Hydrophilic extracts of Scots pine knotwood and black locust heartwood were chemically analyzed, tested for antifungal and antioxidant properties and used for impregnation of beech and Scots pine sapwood. Materials and Methods: Scots pine knotwood and black locust heartwood were extracted, and obtained hydrophilic extractives were chemically analyzed. Extracts were analyzed for antifungal properties with the in vitro well-diffusion method. The free radical scavenging activity of wood extracts was measured colorimetrically. The retention of the extracts in the impregnated sapwood blocks was evaluated with microscopy and gravimetry. A decay test was performed with the mini block test. Results: Almost half of both Scots pine knotwood and black locust heartwood hydrophilic extracts obtained were described by phenolic compounds. The extracts were deposited in the lumina of cells and on the cell wall surface. Extractives of Scots pine knotwood had good inhibitory properties against white- and brown-rot fungi. On the other hand, extractives of black locust heartwood were found to be good radical scavengers, better than knotwood extractives of Scots pine. The extracts of Scots pine knotwood and black locust reduced the fungal decay of the tested sapwood blocks. Conclusions: The results of this research show that the less-valued knotwood of Scots pine and heartwood of black locust are a potential source of antifungal and antioxidant agents for bio-based wood preservatives. Full article

(This article belongs to the Special Issue Performance of Wood and Wood-Based Materials)

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8 pages, 1220 KiB

Open AccessCommentary

Picea abies–Armillaria–Ips: A Strategy or Coincidence?

by Zbigniew Sierota and Wojciech Grodzki

Forests 2020, 11(9), 1023; https://doi.org/10.3390/f11091023 - 22 Sep 2020

Cited by 6 | Viewed by 3398

Abstract

Norway spruce trees weakened by soil drought and progressive die-off of mycorrhizas in root systems become susceptible to infection by rhizomorphs of Armillaria spp. The developing mycelium of this necrotroph induces resin channels in wood, and the induced resin releases some volatile compounds [...] Read more.

Norway spruce trees weakened by soil drought and progressive die-off of mycorrhizas in root systems become susceptible to infection by rhizomorphs of Armillaria spp. The developing mycelium of this necrotroph induces resin channels in wood, and the induced resin releases some volatile compounds which falsely signal bark beetles that it is safe to invade the host. As a result of the developing beetle outbreak, host trees die, becoming a long-term stock of substrate for the fungus in its saprotrophic stage. This hypothesis is discussed as a fungal survival strategy. Full article

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

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21 pages, 3231 KiB

Open AccessArticle

Douglas-Fir Biomass Allocation and Net Nutrient Pools 15–20 Years after Organic Matter Removal and Vegetation Control

by K. M. Littke, T. B. Harrington, S. M. Holub, W. R. Littke, R. B. Harrison and E. C. Turnblom

Forests 2020, 11(9), 1022; https://doi.org/10.3390/f11091022 - 22 Sep 2020

Cited by 8 | Viewed by 2009

Abstract

Douglas-fir (Pseudotsuga menziesiivar. menziesii (Mirbel) Franco) plantation forests of the coastal Pacific Northwest have been intensively managed to improve the yield of forest products. However, the long-term effects of these management techniques have received limited research attention in this region. Three [...] Read more.

Douglas-fir (Pseudotsuga menziesiivar. menziesii (Mirbel) Franco) plantation forests of the coastal Pacific Northwest have been intensively managed to improve the yield of forest products. However, the long-term effects of these management techniques have received limited research attention in this region. Three affiliate Long-Term Soil Productivity study sites were installed in Douglas-fir forests to understand the impacts of organic matter removals and vegetation control on soil productivity over time. Matlock and Fall River are located in Washington, USA and Molalla is located in Oregon. Organic matter removal treatments included traditional bole-only harvest (BO), whole tree removals (WT), and a whole tree plus coarse woody debris removal (WT+) (Fall River only). Five years of annual vegetation control (AVC) was compared with a conventional initial vegetation control (IVC) treatment at all sites. Douglas-fir biomass allocation to foliage, branch, and stem components was modeled using 15- to 20-year-old trees from this study along with 5- to 47-year-old trees from previous studies on these sites. Across all sites, model predictions indicated that the WT treatment had 7.1 to 9.7 Mg ha⁻¹ less Douglas-fir biomass than the BO treatment. There was 1.5 to 20.5 Mg ha⁻¹ greater Douglas-fir biomass in the AVC treatment than in the IVC treatment at all sites. Douglas-fir carbon and nitrogen biomass were consistently lower in the WT treatment, but there were no significant changes in overall site nutrient pools. The AVC treatment resulted in greater Douglas-fir nutrient pools yet there was a net loss in site calcium, magnesium, and potassium due to lower forest floor and soil base cation pools. While WT removals did not significantly affect site nutrition, the decrease in Douglas-fir biomass at all sites and increase in invasive Scotch broom (Cytisus scoparius (L.) Link) biomass at Matlock suggests that the standard practice of retaining harvest residuals is beneficial. The use of intensive vegetation control to improve Douglas-fir biomass and nutrition must be balanced with retaining soil base cations. Full article

(This article belongs to the Special Issue Soil Management and Forest Productivity)

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21 pages, 6552 KiB

Open AccessArticle

Effect of Micromelalopha sieversi (Staudinger) Oviposition Behavior on the Transcriptome of Two Populus Section Aigeiros Clones

by Li Guo, Sufang Zhang, Fu Liu, Xiangbo Kong and Zhen Zhang

Forests 2020, 11(9), 1021; https://doi.org/10.3390/f11091021 - 22 Sep 2020

Cited by 3 | Viewed by 1841

Abstract

Research Highlights: The molecular mechanisms underlying woody plant resistance upon oviposition by herbivores remain unclear, as studies have focused on herbaceous plants. The effect of oviposition on gene expression in neighboring plants has also not been reported. Elucidating these molecular responses can help [...] Read more.

Research Highlights: The molecular mechanisms underlying woody plant resistance upon oviposition by herbivores remain unclear, as studies have focused on herbaceous plants. The effect of oviposition on gene expression in neighboring plants has also not been reported. Elucidating these molecular responses can help cultivate insect-resistant trees. Background and Objectives: Oviposition by herbivorous insects acts as an early warning signal, inducing plant resistance responses. Here, we employed poplar as a model woody plant to elucidate gene expression and the molecular mechanisms underlying plant resistance after oviposition by Micromelalopha sieversi (Staudinger) (Lepidoptera: Notodontidae). Materials and Methods: The differences in gene expression of two Populus section Aigeiros clones (‘108’ (Populus × euramericana ‘Guariento’) and ‘111’ (Populus × euramericana ‘Bellotto’)) were analyzed via high-throughput sequencing of oviposited, neighboring, and control plants. Results: We obtained 304,526,107 reads, with an average length of 300 bp and a total size of 40.77 Gb. Differentially expressed genes (DEGs) in gene ontology terms of biological process, cellular component, and molecular function were mainly enriched in the “cell part”, “catalytic”, and “metabolic process” functions. Moreover, DEGs were mainly enriched in the following pathways: plant-pathogen interaction, linoleic acid metabolism, and cyanoamino acid metabolism (108-O vs. 108-C); metabolic pathways, photosynthesis, photosynthesis-antenna proteins, nitrogen metabolism, and linoleic acid metabolism (111-O vs. 111-C); metabolic pathways and biosynthesis of secondary metabolites (111-N vs. 111-C); no pathways were significantly enriched in 108-N vs. 108-C. Up-regulated defense genes were associated with pathogenesis-related protein function, innate immune regulation, and biological stress response, with differences in specific genes. All genes related to photosynthetic activity were significantly down-regulated in oviposited and neighboring leaves of the two clones. Conclusions: Oviposited and neighboring ‘108’ and ‘111’ plants exhibited varying degrees of resistance upon oviposition, involving the up-regulation of various defense genes, decreased photosynthesis and nutrient accumulation, and increased secondary metabolic synthesis. Full article

(This article belongs to the Special Issue Insects and Forest Ecosystems)

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13 pages, 3384 KiB

Open AccessArticle

Identifying Variables to Discriminate between Conserved and Degraded Forest and to Quantify the Differences in Biomass

by Yan Gao, Margaret Skutsch, Diana Laura Jiménez Rodríguez and Jonathan V. Solórzano

Forests 2020, 11(9), 1020; https://doi.org/10.3390/f11091020 - 22 Sep 2020

Cited by 5 | Viewed by 2080

Abstract

The purpose of this work was to determine which structural variables present statistically significant differences between degraded and conserved tropical dry forest through a statistical study of forest survey data. The forest survey was carried out in a tropical dry forest in the [...] Read more.

The purpose of this work was to determine which structural variables present statistically significant differences between degraded and conserved tropical dry forest through a statistical study of forest survey data. The forest survey was carried out in a tropical dry forest in the watershed of the River Ayuquila, Jalisco state, Mexico between May and June of 2019, when data were collected in 36 plots of 500 m². The sample was designed to include tropical dry forests in two conditions: degraded and conserved. In each plot, data collected included diameter at breast height, tree height, number of trees, number of branches, canopy cover, basal area, and aboveground biomass. Using the Wilcoxon signed-rank test, we show that there are significant differences in canopy cover, tree height, basal area, and aboveground biomass between degraded and conserved tropical dry forest. Among these structural variables, canopy cover and mean height separate conserved and degraded forests with the highest accuracy (both at 80.7%). We also tested which variables best correlate with aboveground biomass, with a view to determining how carbon loss in degraded forest can be quantified at a larger scale using remote sensing. We found that canopy cover, tree height, and density of trees all show good correlation with biomass and these variables could be used to estimate changes in biomass stocks in degraded forests. The results of our analysis will help to increase the accuracy in estimating aboveground biomass, contribute to the ongoing work on REDD+, and help to reduce the great uncertainty in estimation of emissions from forest degradation. Full article

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16 pages, 1613 KiB

Open AccessArticle

Contribution of Non-Timber Forest Product Valorisation to the Livelihood Assets of Local People in the Northern Periphery of the Dja Faunal Reserve, East Cameroon

by Manfred Aimé Epanda, Romaric Tsafack Donkeng, Fidoline Ngo Nonga, Daniel Frynta, Nwafi Ngeayi Adi, Jacob Willie and Stijn Speelman

Forests 2020, 11(9), 1019; https://doi.org/10.3390/f11091019 - 22 Sep 2020

Cited by 11 | Viewed by 2623

Abstract

A large community of scientists has demonstrated that millions of people located in tropical zones derive a significant proportion of their livelihoods from the extraction of non-timber forest products (NTFPs). Despite these results, questions remain as to whether the valorisation of NTFPs can [...] Read more.

A large community of scientists has demonstrated that millions of people located in tropical zones derive a significant proportion of their livelihoods from the extraction of non-timber forest products (NTFPs). Despite these results, questions remain as to whether the valorisation of NTFPs can sustainably contribute to the improvement of the livelihood assets of the extractors. This study therefore evaluated the contribution of NTFP valorisation to the livelihood assets of local people around the northern periphery of the Dja Faunal Reserve (DFR), East Cameroon. To achieve this objective, data collected from 215 households in 32 villages were analyzed using factor analysis, Mann–Whitney U tests, and structural equation modelling. The results suggest that NTFP valorisation significantly contributes to the livelihood assets of local people at the periphery of the DFR. However, NTFP revenue was not significant in predicting their livelihood assets. Moreover, the local conservation management practices were not significant in predicting the livelihood assets in the long run. The results also revealed that individuals who received training and capacity building on good practices such as efficient collection techniques, effective drying techniques, and good conservation techniques earned better revenues and the impact on their livelihood was more significant than for those who did not. These results therefore recommend that the way forward for NTFP valorisation lies at the level of improving its quality and the market. Full article

(This article belongs to the Special Issue The Economics of Forest Ecosystem Services and Biodiversity)

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15 pages, 2620 KiB

Open AccessArticle

Estimating Mangrove Above-Ground Biomass Loss Due to Deforestation in Malaysian Northern Borneo between 2000 and 2015 Using SRTM and Landsat Images

by Charissa J. Wong, Daniel James, Normah A. Besar, Kamlisa U. Kamlun, Joseph Tangah, Satoshi Tsuyuki and Mui-How Phua

Forests 2020, 11(9), 1018; https://doi.org/10.3390/f11091018 - 22 Sep 2020

Cited by 16 | Viewed by 3982

Abstract

Mangrove forests are highly productive ecosystems and play an important role in the global carbon cycle. We used Shuttle Radar Topography Mission (SRTM) elevation data to estimate mangrove above-ground biomass (AGB) in Sabah, Malaysian northern Borneo. We developed a tree-level approach to deal [...] Read more.

Mangrove forests are highly productive ecosystems and play an important role in the global carbon cycle. We used Shuttle Radar Topography Mission (SRTM) elevation data to estimate mangrove above-ground biomass (AGB) in Sabah, Malaysian northern Borneo. We developed a tree-level approach to deal with the substantial temporal discrepancy between the SRTM data and the mangrove’s field measurements. We predicted the annual growth of diameter at breast height and adjusted the field measurements to the SRTM data acquisition year to estimate the field AGB. A canopy height model (CHM) was derived by correcting the SRTM data with ground elevation. Regression analyses between the estimated AGB and SRTM CHM produced an estimation model (R²: 0.61) with a root mean square error (RMSE) of 8.24 Mg ha⁻¹ (RMSE%: 5.47). We then quantified the mangrove forest loss based on supervised classification of multitemporal Landsat images. More than 25,000 ha of mangrove forest had disappeared between 2000 and 2015. This has resulted in a significant decrease of about 3.96 million Mg of mangrove AGB in Sabah during the study period. As SRTM elevation data has a near-global coverage, this approach can be used to map the historical AGB of mangroves, especially in Southeast Asia, to promote mangrove carbon stock conservation. Full article

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

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9 pages, 1793 KiB

Open AccessArticle

Influence of Chain Sharpness, Tension Adjustment and Type of Electric Chainsaw on Energy Consumption and Cross-Cutting Time

by Anton Poje and Matevž Mihelič

Forests 2020, 11(9), 1017; https://doi.org/10.3390/f11091017 - 21 Sep 2020

Cited by 7 | Viewed by 2785

Abstract

Recently, electrical cordless chainsaws were introduced, which provide less harmful working conditions for the operators, and should therefore be deployed as much as possible in all non-professional and professional applications. The low power of the electric engines may result in lower efficiency and [...] Read more.

Recently, electrical cordless chainsaws were introduced, which provide less harmful working conditions for the operators, and should therefore be deployed as much as possible in all non-professional and professional applications. The low power of the electric engines may result in lower efficiency and higher energy consumption in the case of over-tensioned chains, due to increased friction between the saw and the chain. Therefore, a partial factorial experiment with one factor on three levels (saw type) and two factors on two levels was designed, whereby a wooden beam was cross-cut at two levels of chain sharpness and tension. The time of cross-cutting and energy consumption were controlled. The chain tension does not have a significant effect onto time of cross cutting, or electricity consumption. Both have cross-cutting and energy consumption have been found to differ significantly when comparing the saws used in the experiment. The average efficiency of cross cutting using electrical chainsaws reported is 2.35 times lower than when using petrol powered saws. The lower efficiency is caused by the lower engine power of electrical saws, and lower speed of chain rotation. Energy consumption and time of cross cutting are significantly higher when using a blunt chain, with large differences in time of cross cutting and electricity consumption, making the chain sharpness the most important of all controlled factors. In the study, we did not find evidence that over tensioning of the chain increases the time of cross cutting or energy consumption, however the integration of such systems is recommended because of the worker’s safety. Full article

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

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35 pages, 15306 KiB

Open AccessArticle

Applying Multi-Temporal Landsat Satellite Data and Markov-Cellular Automata to Predict Forest Cover Change and Forest Degradation of Sundarban Reserve Forest, Bangladesh

by Mohammad Emran Hasan, Biswajit Nath, A.H.M. Raihan Sarker, Zhihua Wang, Li Zhang, Xiaomei Yang, Mohammad Nur Nobi, Eivin Røskaft, David J. Chivers and Ma Suza

Forests 2020, 11(9), 1016; https://doi.org/10.3390/f11091016 - 21 Sep 2020

Cited by 27 | Viewed by 5287

Abstract

Overdependence on and exploitation of forest resources have significantly transformed the natural reserve forest of Sundarban, which shares the largest mangrove territory in the world, into a great degradation status. By observing these, a most pressing concern is how much degradation occurred in [...] Read more.

Overdependence on and exploitation of forest resources have significantly transformed the natural reserve forest of Sundarban, which shares the largest mangrove territory in the world, into a great degradation status. By observing these, a most pressing concern is how much degradation occurred in the past, and what will be the scenarios in the future if they continue? To confirm the degradation status in the past decades and reveal the future trend, we took Sundarban Reserve Forest (SRF) as an example, and used satellite Earth observation historical Landsat imagery between 1989 and 2019 as existing data and primary data. Moreover, a geographic information system model was considered to estimate land cover (LC) change and spatial health quality of the SRF from 1989 to 2029 based on the large and small tree categories. The maximum likelihood classifier (MLC) technique was employed to classify the historical images with five different LC types, which were further considered for future projection (2029) including trends based on 2019 simulation results from 1989 and 2019 LC maps using the Markov-cellular automata model. The overall accuracy achieved was 82.30%~90.49% with a kappa value of 0.75~0.87. The historical result showed forest degradation in the past (1989–2019) of 4773.02 ha yr⁻¹, considered as great forest degradation (GFD) and showed a declining status when moving with the projection (2019–2029) of 1508.53 ha yr⁻¹ and overall there was a decline of 3956.90 ha yr⁻¹ in the 1989–2029 time period. Moreover, the study also observed that dense forest was gradually degraded (good to bad) but, conversely, light forest was enhanced, which will continue in the future even to 2029 if no effective management is carried out. Therefore, by observing the GFD, through spatial forest health quality and forest degradation mapping and assessment, the study suggests a few policies that require the immediate attention of forest policy-makers to implement them immediately and ensure sustainable development in the SRF. Full article

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21 pages, 4732 KiB

Open AccessArticle

Climate-Biome Envelope Shifts Create Enormous Challenges and Novel Opportunities for Conservation

by Ryan Toot, Lee E. Frelich, Ethan E. Butler and Peter B. Reich

Forests 2020, 11(9), 1015; https://doi.org/10.3390/f11091015 - 21 Sep 2020

Cited by 9 | Viewed by 3846

Abstract

Research Highlights: We modeled climate-biome envelopes at high resolution in the Western Great Lakes Region for recent and future time-periods. The projected biome shifts, in conjunction with heterogeneous distribution of protected land, may create both great challenges for conservation of particular ecosystems and [...] Read more.

Research Highlights: We modeled climate-biome envelopes at high resolution in the Western Great Lakes Region for recent and future time-periods. The projected biome shifts, in conjunction with heterogeneous distribution of protected land, may create both great challenges for conservation of particular ecosystems and novel conservation opportunities. Background and Objectives: Climate change this century will affect the distribution and relative abundance of ecological communities against a mostly static background of protected land. We developed a climate-biome envelope model using a priori climate-vegetation relationships for the Western Great Lakes Region (Minnesota, Wisconsin and Michigan USA and adjacent Ontario, Canada) to predict potential biomes and ecotones—boreal forest, mixed forest, temperate forest, prairie–forest border, and prairie—for a recent climate normal period (1979–2013) and future conditions (2061–2080). Materials and Methods: We analyzed six scenarios, two representative concentration pathways (RCP)—4.5 and 8.5, and three global climate models to represent cool, average, and warm scenarios to predict climate-biome envelopes for 2061–2080. To assess implications of the changes for conservation, we analyzed the amount of land with climate suited for each of the biomes and ecotones both region-wide and within protected areas, under current and future conditions. Results: Recent biome boundaries were accurately represented by the climate-biome envelope model. The modeled future conditions show at least a 96% loss in areas suitable for the boreal and mixed forest from the region, but likely gains in areas suitable for temperate forest, prairie–forest border, and prairie. The analysis also showed that protected areas in the region will most likely lose most or all of the area, 18,692 km², currently climatically suitable for boreal forest. This would represent an enormous conservation loss. However, conversely, the area climatically suitable for prairie and prairie–forest border within protected areas would increase up to 12.5 times the currently suitable 1775 km². Conclusions: These results suggest that retaining boreal forest in potential refugia where it currently exists and facilitating transition of some forests to prairie, oak savanna, and temperate forest should both be conservation priorities in the northern part of the region. Full article

(This article belongs to the Special Issue Impact of Climate Change on Biome Distributions in Forests)

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17 pages, 4795 KiB

Open AccessArticle

Internal Reference Gene Selection under Different Hormone Stresses in Multipurpose Timber Yielding Tree Neolamarckia cadamba

by Deng Zhang, Jingjian Li, Buye Li, Chunmei Li, Xiaoyang Chen and Kunxi Ouyang

Forests 2020, 11(9), 1014; https://doi.org/10.3390/f11091014 - 21 Sep 2020

Cited by 2 | Viewed by 2008

Abstract

Neolamarckia cadamba, a member of the Rubiaceae family, is widely distributed throughout South Asia and South China. In order to acquire reliable and repeatable results, the use of a suitable internal reference gene to normalize the RT-qPCR data is essential. In this [...] Read more.

Neolamarckia cadamba, a member of the Rubiaceae family, is widely distributed throughout South Asia and South China. In order to acquire reliable and repeatable results, the use of a suitable internal reference gene to normalize the RT-qPCR data is essential. In this study, we reported the validation of housekeeping genes to identify the most suitable internal reference gene(s) for normalization of qPCR data obtained among different tissues (bud, leaf, cambium region) under different hormone stresses. Here, ΔCt, geNorm, NormFinder, and BestKeeper analyses were carried out to analyze the normalization of qPCR data of twenty-one reference gene families (ACT, CAC, CYP, EF1α, eIF, FPS1, FBK, GAPDH, RAN, PEPKR1, PP2A, RPL, RPS, RuBP, SAMDC, TEF, Tub-α, Tub-β, UBCE, UBQ, UPL) including 43 genes. The results showed that FPS1, RPL, and FBK were the most stable reference genes across all of the tested samples. In addition, the expression of NcEXPA8, one gene of interest that plays an important role in regulating cell wall extension, under different phytohormone stresses was used to further confirm the validated reference genes. Taken together, our results provide guidelines for reference gene selection under different phytohormone stresses and a foundation for more accurate and widespread use of RT-qPCR in N. cadamba. Full article

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15 pages, 2023 KiB

Open AccessArticle

A 13-Year Approach to Understand the Effect of Prescribed Fires and Livestock Grazing on Soil Chemical Properties in Tivissa, NE Iberian Peninsula

by Meritxell Alcañiz, Xavier Úbeda and Artemi Cerdà

Forests 2020, 11(9), 1013; https://doi.org/10.3390/f11091013 - 21 Sep 2020

Cited by 22 | Viewed by 3205

Abstract

The high density of fuel accumulated in the Mediterranean ecosystems due to land abandonment results in high severity fires. Traditional fire practices and livestock grazing have played an important role in shaping the structure and composition of Mediterranean landscapes, and both can be [...] Read more.

The high density of fuel accumulated in the Mediterranean ecosystems due to land abandonment results in high severity fires. Traditional fire practices and livestock grazing have played an important role in shaping the structure and composition of Mediterranean landscapes, and both can be efficient tools to manage them now that land abandonment is widespread. Attempts at controlling forest fires are essential for landscape management practices that, in their turn, seek to maintain a specific species composition. Against this backdrop, this study aims to determine the short- and long-term effects of the combined management practices of prescribed fires and goat grazing on the chemical properties of soils in Tivissa, Tarragona (NE Iberian Peninsula). Forty-two samples were collected in a 4 × 18 m plot before the prescribed fire of 2002 (1), immediately after the 2002 prescribed fire (PF) (2), one year after the 2002 PF (3), three years after the 2002 PF (4), and thirteen years after the 2002 PF (5). Soil samples were taken at each sampling point from the top layer (0–5 cm), sieved to obtain a <2 mm fraction, and soil pH, EC, Total C, total N, available P, K⁺, Ca²⁺, and Mg²⁺ were determined. The results indicate that the short-term effects of fire are more relevant than those attributable to the livestock over the long term due to the low grazing intensity of less than one goat per ha. The long-term effects of prescribed fires were not visible in the research, suggesting that they recovered after burning with all their functions intact and with enhanced levels of natural fertility. Combined land management practices of prescribed fire and livestock grazing did not affect soil chemical properties. The applied management enhanced soil fertility and boosted the ecosystem’s resilience. Full article

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16 pages, 1730 KiB

Open AccessArticle

Challenges of Sharing REDD+ Benefits in the Amazon Region

by Raissa Guerra and Paulo Moutinho

Forests 2020, 11(9), 1012; https://doi.org/10.3390/f11091012 - 21 Sep 2020

Cited by 8 | Viewed by 3774

Abstract

The success of jurisdictional reducing emissions from deforestation and forest degradation (REDD+) initiatives is entirely dependent on how the REDD+ benefits are distributed among the stakeholders seeking to preserve the native vegetation and is considered one of the main challenges of REDD+. Among [...] Read more.

The success of jurisdictional reducing emissions from deforestation and forest degradation (REDD+) initiatives is entirely dependent on how the REDD+ benefits are distributed among the stakeholders seeking to preserve the native vegetation and is considered one of the main challenges of REDD+. Among the existing benefit-sharing options, the adoption of the stock-and-flow approach to share REDD+ benefits has afforded fair jurisdictional systems in the states of Acre and Mato Grosso in the Brazilian Amazon. This innovative perspective is also the dividing line between inequitable and socially balanced jurisdictional REDD+ initiatives. However, these jurisdictions present challenges to fully implementing a robust benefit-sharing mechanism including the stock-and-flow approach and guaranteeing that resources will be accessible to the relevant beneficiaries. To better understand these challenges, we applied the Options Assessment Framework (OAF), a methodology proposed by the World Bank to evaluate the capacity to implement an effective benefit-sharing mechanism for REDD+, in Acre and Mato Grosso. The results indicated that these jurisdictions need to strengthen their conditions to guarantee the multi-faceted functionality of this mechanism and determine what aspects need more attention and where resources should be invested. Additionally, the results indicated that an equitable benefit-sharing mechanism is, by far, the main challenge faced by jurisdictions. Despite being a more evolved state in its REDD+ policies, Acre still needs to improve its institutional capacities, particularly in its local civil society organizations, to help communities access these benefits. The state of Mato Grosso, on the other hand, is still engaging in its REDD+ initiative and needs its institutional capacities to further mature to better organize its monitoring mechanisms and governance. Full article

(This article belongs to the Special Issue REDD+: Protecting Climate, Forests and Livelihoods)

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21 pages, 1904 KiB

Open AccessArticle

Practical Implications of Different Phenotypic and Molecular Responses of Evergreen Conifer and Broadleaf Deciduous Forest Tree Species to Regulated Water Deficit in a Container Nursery

by Piotr Robakowski, Tomasz P. Wyka, Wojciech Kowalkowski, Władysław Barzdajn, Emilia Pers-Kamczyc, Artur Jankowski and Barbara Politycka

Forests 2020, 11(9), 1011; https://doi.org/10.3390/f11091011 - 20 Sep 2020

Cited by 11 | Viewed by 2804

Abstract

Recent climatic changes have resulted in an increased frequency and prolonged periods of drought and strained water resources affecting plant production. We explored the possibility of reducing irrigation in a container nursery and studied the growth responses of seedlings of four economically important [...] Read more.

Recent climatic changes have resulted in an increased frequency and prolonged periods of drought and strained water resources affecting plant production. We explored the possibility of reducing irrigation in a container nursery and studied the growth responses of seedlings of four economically important forest trees: broadleaf deciduous angiosperms Fagus sylvatica L., Quercus petraea (Matt.) Liebl., and evergreen conifers Abies alba Mill. and Pinus sylvestris L. We also studied markers of water stress including modifications of biomass allocation, leaf anatomy, proline accumulation, and expression of selected genes. Growth of the broadleaved deciduous species was more sensitive to the reduced water supply than that of conifers. Remarkably, growth of the shade tolerant Abies was not affected. Adjustment of biomass allocations was strongest in P. sylvestris, with a remarkable increase in allocation to roots. In response to water deficit both deciduous species accumulated proline in leaves and produced leaves with shorter palisade cells, reduced vascular tissues, and smaller conduit diameters. These responses did not occur in conifers. Relative transcript abundance of a gene encoding the Zn-finger protein in Q. petraea and a gene encoding the pore calcium channel protein 1 in A. alba increased as water deficit increased. Our study shows major differences between functional groups in response to irrigation, with seedlings of evergreen conifers having higher tolerance than the deciduous species. This suggests that major water savings could be achieved by adjusting irrigation regime to functional group or species requirements. Full article

(This article belongs to the Special Issue Drought Resilience of Forest Trees)

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16 pages, 3642 KiB

Open AccessArticle

Comparison of the Scaling Relationships of Leaf Biomass versus Surface Area between Spring and Summer for Two Deciduous Tree Species

by Mengdi Liu, Karl J. Niklas, Ülo Niinemets, Dirk Hölscher, Long Chen and Peijian Shi

Forests 2020, 11(9), 1010; https://doi.org/10.3390/f11091010 - 20 Sep 2020

Cited by 20 | Viewed by 3630

Abstract

The scaling relationship between either leaf dry or fresh mass (M) and surface area (A) can reflect the photosynthetic potential and efficiency of light harvesting in different broad-leaved plants. In growing leaves, lamina area expansion is typically finished before [...] Read more.

The scaling relationship between either leaf dry or fresh mass (M) and surface area (A) can reflect the photosynthetic potential and efficiency of light harvesting in different broad-leaved plants. In growing leaves, lamina area expansion is typically finished before the completion of leaf biomass accumulation, thereby affecting the M vs. A scaling relationship at different developmental stages of leaves (e.g., young vs. adult leaves). In addition, growing plants can have different-sized leaves at different plant ages, potentially also changing M vs. A scaling. Furthermore, leaf shape can also change during the course of ontogeny and modify the M vs. A scaling relationship. Indeed, the effect of seasonal changes in leaf shape on M vs. A scaling has not been examined in any previous studies known to us. The study presented here was conducted using two deciduous tree species: Alangium chinense (saplings forming leaves through the growing season) and Liquidambar formosana (adult trees producing only one leaf flush in spring) that both have complex but nearly bilaterally symmetrical leaf shapes. We determined (i) whether leaf shapes differed in spring versus summer; (ii) whether the M vs. A scaling relationship varied over time; and (iii) whether there is a link between leaf shape and the scaling exponent governing the M vs. A scaling relationship. The data indicated that (i) the leaf dissection index in spring was higher than that in summer for both species (i.e., leaf-shape complexity decreased from young to adult leaves); (ii) there was a significant difference in the numerical value of the scaling exponent of leaf perimeter vs. area between leaves sampled at the two dates; (iii) spring leaves had a higher water content than summer leaves, and the scaling exponents of dry mass vs. area and fresh mass vs. area were all greater than unity; (iv) the scaling relationship between fresh mass and area was statistically more robust than that between leaf dry mass and area; (v) the scaling exponents of leaf dry and fresh mass vs. area of A. chinense leaves in spring were greater than those in summer (i.e., leaves in younger plants tend to be larger than leaves in older plants), whereas, for the adult trees of L. formosana, the scaling exponent in spring was smaller than that in summer, indicating increases in leaf dry mass per unit area with increasing leaf age; and (vi) leaf shape appears not to be related to the scaling relationship between either leaf dry or fresh mass and area, but is correlated with the scaling exponent of leaf perimeter vs. area (which tends to be a ½ power function). These trends indicate that studies of leaf morphometrics and scaling relationships must consider the influence of seasonality and plant age in sampling of leaves and the interpretation of data. Full article

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

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16 pages, 777 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 8 | Viewed by 3096

Abstract

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

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

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

34 pages, 2913 KiB

Open AccessArticle

Assessing Restoration Potential of Fragmented and Degraded Fagaceae Forests in Meghalaya, North-East India

by Prem Prakash Singh, Tamalika Chakraborty, Anna Dermann, Florian Dermann, Dibyendu Adhikari, Purna B. Gurung, Saroj Kanta Barik, Jürgen Bauhus, Fabian Ewald Fassnacht, Daniel C. Dey, Christine Rösch and Somidh Saha

Forests 2020, 11(9), 1008; https://doi.org/10.3390/f11091008 - 19 Sep 2020

Cited by 11 | Viewed by 3533

Abstract

The montane subtropical broad-leaved humid forests of Meghalaya (Northeast India) are highly diverse and situated at the transition zone between the Eastern Himalayas and Indo-Burma biodiversity hotspots. In this study, we have used inventory data from seedlings to canopy level to assess the [...] Read more.

The montane subtropical broad-leaved humid forests of Meghalaya (Northeast India) are highly diverse and situated at the transition zone between the Eastern Himalayas and Indo-Burma biodiversity hotspots. In this study, we have used inventory data from seedlings to canopy level to assess the impact of both biotic and abiotic disturbances on structure, composition, and regeneration potential of the Fagaceae trees of these forests. Fagaceae trees are considered as the keystone species in these forests due to their regional dominance and their importance as a fuel wood source, and also because they form an important component of climax community in these forests. Unfortunately, these forests are highly degraded and fragmented due to anthropogenic disturbances. We have assessed, for the first time, the restoration potential (i.e., capacity to naturally regenerate and sustain desired forest structure) of Fagaceae species in the genera Lithocarpus Blume, Castanopsis (D. Don) Spach, and Quercus Linn. We also evaluated how biotic and abiotic factors, as well as anthropogenic disturbances, influence the restoration potential of these species in six fragmented forest patches located along an elevational gradient on south-facing slopes in the Khasi Hills, Meghalaya. Fagaceae was the most dominant family at all sites except one site (Laitkynsew), where it was co-dominant with Lauraceae. Fagaceae forests have shown high diversity and community assemblages. Fagaceae species had high levels of natural regeneration (i.e., seedlings and saplings) but low recruitment to large trees (diameter at breast height or DBH ≥ 10 cm) at all sites. The ability to sprout was higher in Fagaceae tree species than non-Fagaceae tree species. We have shown that human disturbance and structural diversity were positively related to regeneration of Fagaceae tree species due to high sprouting. However, with increasing human disturbance, recruitment of saplings and pole-sized trees to mature trees hampered the resulting proportion of mature Fagaceae tree species. This study provides a means for assessing regeneration and a basis for forest management strategies in degraded and fragmented forests of Meghalaya. Full article

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

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13 pages, 1637 KiB

Open AccessArticle

A Cointegration Analysis of the Nordic Roundwood Markets

by Victoria Eriksson and Robert Lundmark

Forests 2020, 11(9), 1007; https://doi.org/10.3390/f11091007 - 18 Sep 2020

Cited by 8 | Viewed by 2171

Abstract

The integration of the Nordic timber markets has been analysed to provide market information to various decision-makers, e.g., climate and industrial policies and investment decisions. This study addresses the interlinkage between Nordic (Sweden, Norway and Finland) roundwood markets (Scots pine (Pinus sylvestris [...] Read more.

The integration of the Nordic timber markets has been analysed to provide market information to various decision-makers, e.g., climate and industrial policies and investment decisions. This study addresses the interlinkage between Nordic (Sweden, Norway and Finland) roundwood markets (Scots pine (Pinus sylvestris L.)) and Norway spruce ((Picea abies L.) sawlogs and pulpwood). In total, eleven markets were analysed using quarterly data over the period 2006Q1–2017Q4 where various unit root and stationary tests were performed together with Johansen’s cointegration test. In addition, directional causality analyses between the integrated markets were also performed. The results show that the law-of-one-price (LOP) hypothesis can be rejected for most of the studied markets and that no individual market emerges as the price-leader. Only the Swedish and Norwegian pine sawlog markets are integrated suggesting a single market for both countries. Price affecting national and forest-related policies as well as investments in the forestry sector, forest industries, bioenergy sector and other forest product using sectors, will not disperse into a larger international market structure; instead, the price effect will be national and more likely have a more profound effect. Full article

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

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18 pages, 1533 KiB

Open AccessArticle

Use of Bayesian Modeling to Determine the Effects of Meteorological Conditions, Prescribed Burn Season, and Tree Characteristics on Litterfall of Pinus nigra and Pinus pinaster Stands

by Juncal Espinosa, Óscar Rodríguez De Rivera, Javier Madrigal, Mercedes Guijarro and Carmen Hernando

Forests 2020, 11(9), 1006; https://doi.org/10.3390/f11091006 - 18 Sep 2020

Cited by 6 | Viewed by 2390

Abstract

Research Highlights: Litterfall biomass after prescribed burning (PB) is significantly influenced by meteorological variables, stand characteristics, and the fire prescription. Some of the fire-adaptive traits of the species under study (Pinus nigra and Pinus pinaster) mitigate the effects of PB [...] Read more.

Research Highlights: Litterfall biomass after prescribed burning (PB) is significantly influenced by meteorological variables, stand characteristics, and the fire prescription. Some of the fire-adaptive traits of the species under study (Pinus nigra and Pinus pinaster) mitigate the effects of PB on litterfall biomass. The Bayesian approach, tested here for the first time, was shown to be useful for analyzing the complex combination of variables influencing the effect of PB on litterfall. Background and Objectives: The aims of the study focused on explaining the influence of meteorological conditions after PB on litterfall biomass, to explore the potential influence of stand characteristic and tree traits that influence fire protection, and to assess the influence of fire prescription and fire behavior. Materials and Methods: An experimental factorial design including three treatments (control, spring, and autumn burning), each with three replicates, was established at two experimental sites (N = 18; 50 × 50 m² plots). The methodology of the International Co-operative Program on Assessment and Monitoring of Air Pollution Effects on Forests (ICP forests) was applied and a Bayesian approach was used to construct a generalized linear mixed model. Results: Litterfall was mainly affected by the meteorological variables and also by the type of stand and the treatment. The effects of minimum bark thickness and the height of the first live branch were random. The maximum scorch height was not high enough to affect the litterfall. Time during which the temperature exceeded 60 °C (cambium and bark) did not have an important effect. Conclusions: Our findings demonstrated that meteorological conditions were the most significant variables affecting litterfall biomass, with snowy and stormy days having important effects. Significant effects of stand characteristics (mixed and pure stand) and fire prescription regime (spring and autumn PB) were shown. The trees were completely protected by a combination of low-intensity PB and fire-adaptive tree traits, which prevent direct and indirect effects on litterfall. Identification of important variables can help to improve PB and reduce the vulnerability of stands managed by this method. Full article

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

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12 pages, 3960 KiB

Open AccessArticle

The Invasive Box Tree Moth Five Years after Introduction in Slovakia: Damage Risk to Box Trees in Urban Habitats

by Ján Kulfan, Peter Zach, Juraj Holec, Peter M.J. Brown, Lenka Sarvašová, Jiří Skuhrovec, Zdenka Martinková, Alois Honěk, Jozef Váľka, Milada Holecová and Miroslav Saniga

Forests 2020, 11(9), 999; https://doi.org/10.3390/f11090999 - 17 Sep 2020

Cited by 5 | Viewed by 3144

Abstract

The box tree moth Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) is an invasive species in Europe and a serious pest of box trees (Buxus spp.). In Slovakia, Central Europe, it was first reported in 2012 within the low elevation region with a [...] Read more.

The box tree moth Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) is an invasive species in Europe and a serious pest of box trees (Buxus spp.). In Slovakia, Central Europe, it was first reported in 2012 within the low elevation region with a warm climate. We hypothesize that the cold mountain region of Slovakia would provide less suitable conditions for the spread of this species, indicated by no or only slight damage to box trees. Five years after C. perspectalis was first recorded in Slovakia, we assessed the probability of occurrence of the moth and the probability of damage to box trees (Buxus sempervirens) by its larvae, using temperature and altitude data as predictors. In June and July 2017, at 156 locations (towns and villages) between the altitudes of 109 and 888 m, we recorded damage and categorized the intensity of damage to box trees by C. perspectalis using a four-point scale. Box trees infested by C. perspectalis were recorded in most locations at altitudes between 110 and 400 m with the mean annual temperature varying between 10.5 and 7.9 °C. High damage to box trees was found in locations up to 340 m a.s.l. characterized by mean annual temperatures above 8.5 °C. Our results suggested high probability (>60%) of any damage to box trees for the area up to approximately 300 m a.s.l. (mean annual temperature above 8.4 °C), and high probability (>60%) of high damage for the area up to approximately 250 m a.s.l. (mean annual temperature above 9 °C). The area where damage to box trees was predicted using the altitude showed great overlap with the area predicted using the mean annual temperature. The area with the probability of any damage was only slightly larger than the area with the probability of high damage. Full article

(This article belongs to the Special Issue Pests and Pathogens of Urban Trees)

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15 pages, 3349 KiB

Open AccessCommunication

Allowing Users to Benefit from Tree Shading: Using a Smartphone App to Allow Adaptive Route Planning during Extreme Heat

by Kaveh Deilami, Julie Rudner, Andrew Butt, Tania MacLeod, Geoff Williams, Harmen Romeijn and Marco Amati

Forests 2020, 11(9), 998; https://doi.org/10.3390/f11090998 - 17 Sep 2020

Cited by 13 | Viewed by 3523

Abstract

This paper presents the outcomes from a joint research project that aims to develop a smartphone application/online platform to model the most thermally comfortable active transport route to a planned destination using heat information and tree shading (Shadeway). Here, we provide a summary [...] Read more.

This paper presents the outcomes from a joint research project that aims to develop a smartphone application/online platform to model the most thermally comfortable active transport route to a planned destination using heat information and tree shading (Shadeway). Here, we provide a summary of our systematic review of academic literature and applications from the Google Play and Apple App Store, to identify current knowledge about personal adaptation strategies when navigating travel in cities during high temperatures. The review identifies that there is a lack of attention regarding the use of smartphone applications to address urban thermal comfort for active transport by government and private industry. We then present the initial results of original research from three community focus groups and an online survey that elicited participants’ opinions about Shadeways in the City of Greater Bendigo (CoGB), Australia. The results clearly show the need for better management of Shadeways in CoGB. For example, 52.3% of the routes traveled by participants suffer from either no or poor levels of shading, and 53 of the shaded areas were located along routes that also experience heavy traffic, which can have an adverse effect on perceptions and actual safety. It is expected that this study will contribute to improve understanding of the methods used to identify adaptation strategies to increasingly extreme temperatures. Full article

(This article belongs to the Special Issue Improved Management of Trees, Ecohydrology, Natural Resources and Microclimate to Mitigate Urban Heat)

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16 pages, 7439 KiB

Open AccessArticle

Effect of Silviculture on Carbon Pools during Development of a Ponderosa Pine Plantation

by Jie Zhang, Jianwei Zhang, Kim Mattson and Kaelyn Finley

Forests 2020, 11(9), 997; https://doi.org/10.3390/f11090997 - 17 Sep 2020

Cited by 5 | Viewed by 1880

Abstract

Forest stands can be considered as dynamic carbon pools throughout their developmental stages. Silvicultural thinning and initial planting densities for reforestation not only manipulate the structure or composition of vegetation, but also disturb forest floor and soils, which, in turn, influences the dynamics [...] Read more.

Forest stands can be considered as dynamic carbon pools throughout their developmental stages. Silvicultural thinning and initial planting densities for reforestation not only manipulate the structure or composition of vegetation, but also disturb forest floor and soils, which, in turn, influences the dynamics of carbon pools. Understanding these carbon pools both spatially and temporally can provide useful information for land managers to achieve their management goals. Here, we estimated five major carbon pools in experimental ponderosa pine (Pinus ponderosa) plots that were planted to three levels of spacing and where competing vegetation was either controlled (VC) or not controlled (NVC). The objectives were to determine how an early competing vegetation control influences the long-term carbon dynamics and how stand density affects the maximum carbon (C) sequestration for these plantations. We found that planting density did not affect total ecosystem C at either sampling age 28 or 54. Because of competing vegetation ingrowth, the NVC (85 ± 14 Mg ha⁻¹) accumulated greater C than the VC (61 ± 6 Mg ha⁻¹) at age 28. By age 54, the differences between treatments narrow with the NVC (114 ± 11 Mg ha⁻¹) and the VC (106 ± 11 Mg ha⁻¹) as the pines continue to grow relatively faster in the VC when compared to NVC and C of ingrowth vegetation decreased in NVC, presumably due to shading by the overstory pines. The detritus was not significantly different among treatments in either years, although the mean forest floor and soil C was slightly greater in NVC. While NVC appears to sequester more C early on, the differences from the VC were rather subtle. Clearly, as the stands continue to grow, the C of the larger pines of the VC may overtake the total C of the NVC. We conclude that, to manage forests for carbon, we must pay more attention to promoting growth of overstory trees by controlling competing vegetation early, which will provide more opportunities for foresters to create resilient forests to disturbances and store C longer in a changing climate. Full article

(This article belongs to the Special Issue Forest Silviculture and Carbon Sequestration in a Changing Climate)

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23 pages, 4227 KiB

Open AccessArticle

Prediction of the Suitable Area of the Chinese White Pines (Pinus subsect. Strobus) under Climate Changes and Implications for Their Conservation

by Lele Lin, Jian He, Lei Xie and Guofa Cui

Forests 2020, 11(9), 996; https://doi.org/10.3390/f11090996 - 17 Sep 2020

Cited by 13 | Viewed by 3029

Abstract

White pines (Pinus subsect. Strobus) play important roles in forest ecosystems in the Northern Hemisphere. Species of this group are narrowly distributed or endangered in China. In this study, we used a species distribution model (SDM) to project and predict the [...] Read more.

White pines (Pinus subsect. Strobus) play important roles in forest ecosystems in the Northern Hemisphere. Species of this group are narrowly distributed or endangered in China. In this study, we used a species distribution model (SDM) to project and predict the distribution patterns of the 12 species of Chinese white pine under a variety of paleoclimatic and future climate change scenarios based on 39 high-resolution environmental variables and 1459 distribution records. We also computed the centroid shift, range expansion/contraction, and suitability change of the current distribution area to assess the potential risk to each species in the future. The modeling results revealed that the suitable habitat of each species is consistent with but slightly larger than its actual distribution range and that temperature, precipitation, and UV radiation are important determining factors for the distribution of different white pine species. The results indicate that the Last Glacial Maximum (LGM) greatly affected the current distribution of the Chinese white pine species. Additionally, it was predicted that under the future climate change scenarios, there will be a reduction in the area of habitats suitable for P. armandii, P. morrisonicola, and P. mastersiana. Furthermore, some of the current distribution sites of P. armandii, P. kwangtungensis, P. mastersiana, P. morrisonicola, P. sibirica, and P. wallichiana were predicted to become more unsuitable under these scenarios. These results indicate that some Chinese white pine species, such as P. armandii, P. morrisonicola, and P. mastersiana, may have a very high risk of population shrinkage in the future. Overall, this study provided relevant data for the long-term conservation (both in situ and ex situ) and sustainable management of Chinese white pine species. Full article

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

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30 pages, 5233 KiB

Open AccessArticle

Mixed Effectiveness of REDD+ Subnational Initiatives after 10 Years of Interventions on the Yucatan Peninsula, Mexico

by Edward A. Ellis, José Antonio Sierra-Huelsz, Gustavo Celestino Ortíz Ceballos, Citlalli López Binnqüist and Carlos R. Cerdán

Forests 2020, 11(9), 1005; https://doi.org/10.3390/f11091005 - 17 Sep 2020

Cited by 11 | Viewed by 8296

Abstract

Since 2010, the Reducing Emissions from Deforestation and Degradation (REDD+) mechanism has been implemented in Mexico’s Yucatan Peninsula, a biodiversity hotspot with persistent deforestation problems. We apply the before-after-control-intervention approach and quasi-experimental methods to evaluate the effectiveness of REDD+ interventions in reducing deforestation [...] Read more.

Since 2010, the Reducing Emissions from Deforestation and Degradation (REDD+) mechanism has been implemented in Mexico’s Yucatan Peninsula, a biodiversity hotspot with persistent deforestation problems. We apply the before-after-control-intervention approach and quasi-experimental methods to evaluate the effectiveness of REDD+ interventions in reducing deforestation at municipal (meso) and community (micro) scales. Difference-in-differences regression and propensity score matching did not show an overall reduction in forest cover loss from REDD+ projects at both scales. However, Synthetic Control Method (SCM) analyses demonstrated mixed REDD+ effectiveness among intervened municipalities and communities. Funding agencies and number of REDD+ projects intervening in a municipality or community did not appear to affect REDD+ outcomes. However, cattle production and commercial agriculture land uses tended to impede REDD+ effectiveness. Cases of communities with important forestry enterprises exemplified reduced forest cover loss but not when cattle production was present. Communities and municipalities with negative REDD+ outcomes were notable along the southern region bordering Guatemala and Belize, a remote forest frontier fraught with illegal activities and socio-environmental conflicts. We hypothesize that strengthening community governance and organizational capacity results in REDD+ effectiveness. The observed successes and problems in intervened communities deserve closer examination for REDD+ future planning and development of strategies on the Yucatan Peninsula. Full article

(This article belongs to the Special Issue REDD+: Protecting Climate, Forests and Livelihoods)

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20 pages, 5025 KiB

Open AccessArticle

A Permanent Research Platform for Ecological Studies in Intact Temperate Mountainous Forests from Slătioara UNESCO Site and Its Surroundings, Romania

by Gabriel Duduman, Mihai-Leonard Duduman, Daniel Avăcăriței, Ionuț Barnoaiea, Cătălina-Oana Barbu, Ioan Ciornei, Florin Clinovschi, Vasile Cosmin Coșofreț, Mihai-Gabriel Cotos, Gabriel Dănilă, Iulian-Constantin Dănilă, Marian Drăgoi, Marcel-Neculai Flocea, Sergiu-Andrei Horodnic, Ovidiu Iacobescu, Georgel Constantin Mazăre, Anca Măciucă, Andrei Mursa, Ciprian Palaghianu, Corneliu Mihăiță Pohonțu, Cătălin-Constantin Roibu, Alexei Savin, Cezar Valentin Tomescu and Ramona-Elena Scriban Show full author list Hide full author list

Forests 2020, 11(9), 1004; https://doi.org/10.3390/f11091004 - 17 Sep 2020

Cited by 2 | Viewed by 3481

Abstract

This paper describes a permanent research platform (PRP) designed and implemented in “Codrul secular Slătioara” and its surroundings (2205.85 ha), having also the role of introductory paper for future research articles based on data collected from this platform. “Codrul secular Slătioara” is known [...] Read more.

This paper describes a permanent research platform (PRP) designed and implemented in “Codrul secular Slătioara” and its surroundings (2205.85 ha), having also the role of introductory paper for future research articles based on data collected from this platform. “Codrul secular Slătioara” is known as one of the largest temperate mountainous intact forests of Europe and, in 2017, it was included in UNESCO World Heritage List, as part of the “Ancient and Primeval Beech Forests of the Carpathians and Other Regions of Europe”. Moreover, the PRP overlaps other three scientific reserves, the share of strictly protected forests exceeding 70%. This platform has a multiple role, being developed for research, conservation and educational activities. The PRP was designed for an ecological analysis of the intact forest ecosystems. It contains 193 circular sample plots, each of them of 500 m², and it is structured on two levels. The first level contains 58 sample plots corresponding to a square grid of 500 × 500 m, stretching over the entire forested area, and the second level contains 135 plots, placed according to a square grid of 100 × 100 m, covering 136 ha within the core area of the UNESCO site. We measured the characteristics of 8296 living trees, 1743 standing dead trees, 1900 dead wood trunks, 3214 saplings, and the abundance–dominance indices of flora species. Thus, we identified 14 tree species, 17 shrub species, and 248 other cormophyte species forming the herbaceous layer. In terms of volume, the main tree species are Norway spruce, silver fir and European beech. The tallest species are Norway spruce (56 m) and silver fir (51 m). The average volume of living trees is 659 m³·ha⁻¹, with a maximum of 1441 m³·ha⁻¹. The mean total dead wood volume is about 158 m³·ha⁻¹, with sample plots where the total dead wood volume exceeds 600 m³·ha⁻¹. After presenting the results of preliminary data processing, the paper describes the main research topics to be further considered, based on the PRP, and the foresights related to the PRP’s monitoring and development. Full article

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15 pages, 1534 KiB

Open AccessArticle

Geographic Variations of the Wood Density and Fiber Dimensions of the Persian Oak Wood

by Noorollah Nazari, Mohsen Bahmani, Saleh Kahyani, Miha Humar and Gerald Koch

Forests 2020, 11(9), 1003; https://doi.org/10.3390/f11091003 - 17 Sep 2020

Cited by 17 | Viewed by 2483

Abstract

Persian oak (Quercus brantii Lindl.) is a valuable native species in Iranian forests with very limited availability of data on its wood properties. The objective of the current study was to determine the influence of altitude and slope on physical properties and [...] Read more.

Persian oak (Quercus brantii Lindl.) is a valuable native species in Iranian forests with very limited availability of data on its wood properties. The objective of the current study was to determine the influence of altitude and slope on physical properties and fiber dimensions of Persian oak wood. In addition, the relationship among wood properties, site conditions (temperature and rainfall) and growth traits of trees (tree height, DBH, basal area, age, crown diameter, crown basal area, volume and annual diameter increment) were studied by principal component analysis (PCA). Three altitude levels (1730, 1980 and 2250 m) and three slope classes (<30%, 30–45% and >45%) were considered in the current study. It was determined that trees growing in the intermediate altitude (1980 m) showed the highest oven-dry density values, and those in the lowest altitude (1730 m) revealed the lowest ones. The results also indicate significant statistical differences between altitude levels and slope classes on the fiber length, fiber diameter and volumetric swelling at the 99% confidence interval while no significant differences were found between average values of oven-dry density among different altitudes and slopes. PCA analysis indicated that altitude and temperature are the most important factors affecting the wood properties. Knowledge of the relationship between wood properties and environmental factors are essential in terms of both forestry management and wood applications. Full article

(This article belongs to the Special Issue Wood Structure and Properties)

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16 pages, 12266 KiB

Open AccessArticle

Linkages between Climate, Radial Growth and Defoliation in Abies pinsapo Forests from Southern Spain

by Rafael M. Navarro-Cerrillo, Antonio Gazol, Carlos Rodríguez-Vallejo, Rubén D. Manzanedo, Guillermo Palacios-Rodríguez and J. J. Camarero

Forests 2020, 11(9), 1002; https://doi.org/10.3390/f11091002 - 17 Sep 2020

Cited by 9 | Viewed by 2918

Abstract

Systematic forest networks of health monitoring have been established to follow changes in tree vigor and mortality. These networks often lack long-term growth data, but they could be complemented with tree ring data, since both defoliation and radial growth are proxies of changes [...] Read more.

Systematic forest networks of health monitoring have been established to follow changes in tree vigor and mortality. These networks often lack long-term growth data, but they could be complemented with tree ring data, since both defoliation and radial growth are proxies of changes in tree vigor. For instance, a severe water shortage should reduce growth and increase tree defoliation in drought-prone areas. However, the effects of climatic stress and drought on growth and defoliation could also depend on tree age. To address these issues, we compared growth and defoliation data with recent climate variability and drought severity in Abies pinsapo old and young trees sampled in Southern Spain, where a systematic health network (Andalucía Permanent Plot Network) was established. Our aims were: (i) to assess the growth sensitivity of old and young A. pinsapo trees and (ii) to test if relative changes in radial growth were related with recent defoliation, for instance, after severe droughts. We also computed the resilience indices to quantify how old and young trees recovered growth after recent droughts. Wet-cool conditions during the prior autumn and the current early summer improved the growth of old trees, whereas late-spring wet conditions enhanced the growth of young trees. Old trees were more sensitive to wet and sunny conditions in the early summer than young trees. Old and young trees were more responsive to the Standardized Precipitation-Evapotranspiration Index drought index of June–July and July–August calculated at short (one–three months) and mid (three–six months) time scales, respectively. Old trees presented a higher resistance to a severe drought in 1995 than young trees. A positive association was found between stand defoliation and relative growth. Combining monitoring and tree ring networks is useful for the detection of early warning signals of dieback in similar drought-prone forests. Full article

(This article belongs to the Special Issue Dendroecological Wood Anatomy and Xylogenesis)

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24 pages, 3879 KiB

Open AccessArticle

Predicting the Outdoor Moisture Performance of Wood Based on Laboratory Indicators

by Lukas Emmerich, Christian Brischke, Marten Sievert, Manuel S. Schulz, Anne-Cathrin Jaeger, Arne Beulshausen and Miha Humar

Forests 2020, 11(9), 1001; https://doi.org/10.3390/f11091001 - 17 Sep 2020

Cited by 10 | Viewed by 2187

Abstract

The service life of wood in outdoor use under humid conditions is mainly determined by its material resistance and the exposure situation. Different standards such as EN 350 (2016) point on the relevance of wood’s resistance against moisture for its expected service life. [...] Read more.

The service life of wood in outdoor use under humid conditions is mainly determined by its material resistance and the exposure situation. Different standards such as EN 350 (2016) point on the relevance of wood’s resistance against moisture for its expected service life. Recently, different standardized but also numerous nonstandardized methods were suggested to test the water permeability of wooden materials. In the context of this study, different European-grown soft- and hardwoods, tropical hardwoods, modified wood and wood treated with water- and oil-borne preservatives were subjected to floating and submersion tests according to CEN/TS 16818 (2018) and different short-term water uptake and release tests. Moisture performance data from field tests with the same materials were analyzed and used to assess the predictive power of different laboratory moisture indicators. The moisture characteristics suggested by CEN/TS 16818 (2018)—rm₁₆₈ (residual moisture content after water uptake and release processes) and res₃₁₂ (residue as a percentage of the absorbed moisture)—showed the little potential to predict the outdoor moisture performance of the tested materials. In contrast, the mean moisture content during absorption and desorption (MC_mean) predicted well the outdoor moisture performance of the materials under test. Short-term water uptake and release of small specimens also showed high predictive power. Full article

(This article belongs to the Special Issue Modeling the Performance of Wood and Wood Products)

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17 pages, 6533 KiB

Open AccessArticle

An Artificial Intelligence Approach to Predict Gross Primary Productivity in the Forests of South Korea Using Satellite Remote Sensing Data

by Bora Lee, Nari Kim, Eun-Sook Kim, Keunchang Jang, Minseok Kang, Jong-Hwan Lim, Jaeil Cho and Yangwon Lee

Forests 2020, 11(9), 1000; https://doi.org/10.3390/f11091000 - 17 Sep 2020

Cited by 22 | Viewed by 3917

Abstract

Many process-based models for carbon flux predictions have faced a wide range of uncertainty issues. The complex interactions between the atmosphere and the forest ecosystems can lead to uncertainties in the model result. On the other hand, artificial intelligence (AI) techniques, which are [...] Read more.

Many process-based models for carbon flux predictions have faced a wide range of uncertainty issues. The complex interactions between the atmosphere and the forest ecosystems can lead to uncertainties in the model result. On the other hand, artificial intelligence (AI) techniques, which are novel methods to resolve complex and nonlinear problems, have shown a possibility for forest ecological applications. This study is the first step to present an objective comparison between multiple AI models for the daily forest gross primary productivity (GPP) prediction using satellite remote sensing data. We built the AI models such as support vector machine (SVM), random forest (RF), artificial neural network (ANN), and deep neural network (DNN) using in-situ observations from an eddy covariance (EC) flux tower and satellite remote sensing data such as albedo, aerosol, temperature, and vegetation index. We focused on the Gwangneung site from the Korea Regional Flux Network (KoFlux) in South Korea, 2006–2015. As a result, the DNN model outperformed the other three models through an intensive hyperparameter optimization, with the correlation coefficient (CC) of 0.93 and the mean absolute error (MAE) of 0.68 g m⁻² d⁻¹ in a 10-fold blind test. We showed that the DNN model also performed well under conditions of cold waves, heavy rain, and an autumnal heatwave. As future work, a comprehensive comparison with the result of process-based models will be necessary using a more extensive EC database from various forest ecosystems. Full article

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

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Forests, Volume 11, Issue 9 (September 2020) – 128 articles

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