Next Issue
Volume 12, November
Previous Issue
Volume 12, September
 
 

Forests, Volume 12, Issue 10 (October 2021) – 135 articles

Cover Story (view full-size image): Broadleaved tree species change the size and shape of their leaves with altitude. We investigated this altitudinal trend in an elevational gradient in a mountainous European beech forest, under habitat types characterized by different environmental conditions. As expected, with increasing altitude, leaves became smaller and rounder. However, this trend was different—even reversed—across different habitat types, different altitude groups, and leaves varying in their position within the tree canopy. This morphological variability can be explained by the various environmental parameters related to altitude and their effect on the adaptive strategy of individual trees and indicates high potential for adaptation to environmental extremes. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
12 pages, 1560 KiB  
Article
The Effects of Combining the Variables in Allometric Biomass Models on Biomass Estimates over Large Forest Areas: A European Beech Case Study
by Erick O. Osewe and Ioan Dutcă
Forests 2021, 12(10), 1428; https://doi.org/10.3390/f12101428 - 19 Oct 2021
Viewed by 1720
Abstract
Effective initiatives for forest-based mitigation of climate change rely on continuous efforts to improve the estimation of forest biomass. Allometric biomass models, which are nonlinear models that predict aboveground biomass (AGB) as a function of diameter at breast height (D [...] Read more.
Effective initiatives for forest-based mitigation of climate change rely on continuous efforts to improve the estimation of forest biomass. Allometric biomass models, which are nonlinear models that predict aboveground biomass (AGB) as a function of diameter at breast height (D) and tree height (H), are typically used in forest biomass estimations. A combined variable D2H may be used instead of two separate predictors. The Q-ratio (i.e., the ratio between the parameter estimates of D and parameter estimates of H, in a separate variable model) was proposed recently as a measure to guide the decision on whether D and H can be safely combined into D2H, being shown that the two model forms are similar when Q = 2.0. Here, using five European beech (Fagus sylvatica L.) biomass datasets (of different Q-ratios ranging from 1.50 to 5.05) and an inventory dataset for the same species, we investigated the effects of combining the variables in allometric models on biomass estimation over large forest areas. The results showed that using a combined variable model instead of a separate variable model to predict biomass of European beech trees resulted in overestimation of mean AGB per hectare for Q > 2.0 (i.e., by 6.3% for Q = 5.05), underestimation for Q < 2.0 (i.e., by –3.9% for Q = 1.50), whereas for Q = 2.03, the differences were minimum (0.1%). The standard errors of mean AGB per hectare were similar for Q = 2.03 (differences up to 0.2%), and the differences increased with the Q-ratio, by up to 10.2% for Q = 5.05. Therefore, we demonstrated for European beech that combining the variables in allometric biomass models when Q ≠ 2.0 resulted in biased estimates of mean AGB per hectare and of uncertainty. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
Show Figures

Figure 1

15 pages, 1760 KiB  
Article
Consistent Effects of Canopy vs. Understory Nitrogen Addition on Soil Respiration and Net Ecosystem Production in Moso Bamboo Forests
by Chunju Cai, Zhihan Yang, Liang Liu, Yunsen Lai, Junjie Lei, Shaohui Fan and Xiaolu Tang
Forests 2021, 12(10), 1427; https://doi.org/10.3390/f12101427 - 19 Oct 2021
Cited by 6 | Viewed by 2001
Abstract
Nitrogen (N) deposition has been well documented to cause substantial impacts on ecosystem carbon cycling. However, the majority studies of stimulating N deposition by direct N addition to forest floor have neglected some key ecological processes in forest canopy (e.g., N retention and [...] Read more.
Nitrogen (N) deposition has been well documented to cause substantial impacts on ecosystem carbon cycling. However, the majority studies of stimulating N deposition by direct N addition to forest floor have neglected some key ecological processes in forest canopy (e.g., N retention and absorption) and might not fully represent realistic atmospheric N deposition and its effects on ecosystem carbon cycling. In this study, we stimulated both canopy and understory N deposition (50 and 100 kg N ha−1 year−1) with a local atmospheric NHx:NOy ratio of 2.08:1, aiming to assess whether canopy and understory N deposition had similar effects on soil respiration (RS) and net ecosystem production (NEP) in Moso bamboo forests. Results showed that RS, soil autotrophic (RA), and heterotrophic respiration (RH) were 2971 ± 597, 1472 ± 579, and 1499 ± 56 g CO2 m−2 year−1 for sites without N deposition (CN0), respectively. Canopy and understory N deposition did not significantly affect RS, RA, and RH, and the effects of canopy and understory N deposition on these soil fluxes were similar. NEP was 1940 ± 826 g CO2 m−2 year−1 for CN0, which was a carbon sink, indicating that Moso bamboo forest the potential to play an important role alleviating global climate change. Meanwhile, the effects of canopy and understory N deposition on NEP were similar. These findings did not support the previous predictions postulating that understory N deposition would overestimate the effects of N deposition on carbon cycling. However, due to the limitation of short duration of N deposition, an increase in the duration of N deposition manipulation is urgent and essential to enhance our understanding of the role of canopy processes in ecosystem carbon fluxes in the future. Full article
(This article belongs to the Section Forest Ecology and Management)
Show Figures

Figure 1

17 pages, 2898 KiB  
Article
Residual Influence of Nitrogen, Phosphorus and Potassium Doses on Soil and Eucalyptus Nutrition in Coppice
by Natasha Mirella Inhã Godoi, Rodolfo de Niro Gazola, Salatiér Buzetti, Arshad Jalal, Thiago de Souza Celestrino, Carlos Eduardo da Silva Oliveira, Thiago Assis Rodrigues Nogueira, Alan Rodrigo Panosso and Marcelo Carvalho Minhoto Teixeira Filho
Forests 2021, 12(10), 1426; https://doi.org/10.3390/f12101426 - 19 Oct 2021
Cited by 1 | Viewed by 1784
Abstract
The management of fertilizer is an important strategy for better nutrition and productivity of eucalyptus. Therefore, the objective of this research was to evaluate the isolated residual effect (carryover) of N, P and K fertilization on macro- and micronutrients in soil, leaf litter, [...] Read more.
The management of fertilizer is an important strategy for better nutrition and productivity of eucalyptus. Therefore, the objective of this research was to evaluate the isolated residual effect (carryover) of N, P and K fertilization on macro- and micronutrients in soil, leaf litter, leaf nutritional diagnosis and initial growth attributes of eucalyptus in a coppice system. Three experiments were carried out in a randomized block design with five replications. Experiment 1: four residual doses of N (0, 70, 105 and 140 kg ha−1) were applied as ammonium nitrate. Experiment 2: four residual doses of P2O5 (0, 40, 70 and 100 kg ha−1) were applied to plantations in furrows using triple superphosphate. Experiment 3: four residual K2O doses (0, 90, 135 and 180 kg ha−1) were applied as potassium chloride. The residual N doses did not influence leaf nutrient contents and initial growth of eucalyptus; however, increasing P residual doses increased soil P and Zn content, litter K content, decreased leaf Mg content, and increased initial growth (height and wood volume of eucalyptus). The residual K doses increased leaf litter K content and leaf Mn and Zn content but decreased leaf litter Ca, B and Fe and leaf Mg content. Residual potassium fertilization did not significantly influence the initial growth of eucalyptus in the Brazilian Cerrado. Full article
(This article belongs to the Special Issue Forest Soil Properties and Nutrient Dynamics under a Semiarid Climate)
Show Figures

Figure 1

17 pages, 5586 KiB  
Article
Impact of Gene Flow and Introgression on the Range Wide Genetic Structure of Quercus robur (L.) in Europe
by Bernd Degen, Yulai Yanbaev, Malte Mader, Ruslan Ianbaev, Svetlana Bakhtina, Hilke Schroeder and Celine Blanc-Jolivet
Forests 2021, 12(10), 1425; https://doi.org/10.3390/f12101425 - 19 Oct 2021
Cited by 15 | Viewed by 3242
Abstract
As for most other temperate broadleaved tree species, large-scale genetic inventories of pedunculate oak (Quercus robur L.) have focused on the plastidial genome, which showed the impact of post-glacial recolonization and manmade seed transfer. However, how have pollen mediated gene flow and [...] Read more.
As for most other temperate broadleaved tree species, large-scale genetic inventories of pedunculate oak (Quercus robur L.) have focused on the plastidial genome, which showed the impact of post-glacial recolonization and manmade seed transfer. However, how have pollen mediated gene flow and introgression impacted the large-scale genetic structure? To answer these questions, we did a genetic inventory on 1970 pedunculate oak trees from 197 locations in 13 European countries. All samples were screened with a targeted sequencing approach on a set of 381 polymorphic loci (356 nuclear SNPs, 3 nuclear InDels, 17 chloroplast SNPs, and 5 mitochondrial SNPs). In a former analysis with additional 1763 putative Quercus petraea trees screened for the same gene markers we obtained estimates on the species admixture of all pedunculate oak trees. We identified 13 plastidial haplotypes, which showed a strong spatial pattern with a highly significant autocorrelation up to a range of 1250 km. Significant spatial genetic structure up to 1250 km was also observed at the nuclear loci. However, the differentiation at the nuclear gene markers was much lower compared to the organelle gene markers. The matrix of genetic distances among locations was partially correlated between nuclear and organelle genomes. Bayesian clustering analysis revealed the best fit to the data for a sub-division into two gene pools. One gene pool is dominating the west and the other is the most abundant in the east. The western gene pool was significantly influenced by introgression from Quercus petraea in the past. In Germany, we identified a contact zone of pedunculate oaks with different introgression intensity, likely resulting from different historical levels of introgression in glacial refugia or during postglacial recolonization. The main directions of postglacial recolonization were south to north and south to northwest in West and Central Europe, and for the eastern haplotypes also east to west in Central Europe. By contrast, the pollen mediated gene flow and introgression from Q. petraea modified the large-scale structure at the nuclear gene markers with significant west–east direction. Full article
(This article belongs to the Section Genetics and Molecular Biology)
Show Figures

Figure 1

12 pages, 3373 KiB  
Article
Phenology of Oenocarpus mapora H. Karst in Low-Terrace and High-Terrace Forests of the Madre de Dios Region, Peru
by Ivan Best, Helmut Rengifo, Ernesto Velarde, Juan Francisco Loja, Alan Portugal, Piero Rengifo, Luis Aguilar, Fernando Ramos-Escudero and Ana María Muñoz
Forests 2021, 12(10), 1424; https://doi.org/10.3390/f12101424 - 19 Oct 2021
Cited by 2 | Viewed by 2828
Abstract
Oenacarpus mapora H. Karst (O. mapora) is an Amazon palm with high economic and nutraceutical potential, from which the pulp and oil can be extracted. The objective of this study was to evaluate the phenology of O. mapora in low-terrace and [...] Read more.
Oenacarpus mapora H. Karst (O. mapora) is an Amazon palm with high economic and nutraceutical potential, from which the pulp and oil can be extracted. The objective of this study was to evaluate the phenology of O. mapora in low-terrace and high-terrace forests of the Madre de Dios Region, Peru. Two hundred sixteen individuals of O. mapora were monitored between June 2019 and January 2020, evaluating the presence of flower buds, open flowers, immature fruits and ripe fruits. Weighted mean analyses of the phenological pattern and correlation between climatic and phenological variables were carried out. Higher productivity mediated by a greater number of mature green leaves and bunches was observed in terrace forests located at a lower altitude. In both forest subtypes, flower buds and open flowers were continuous with a peak in July and August, respectively, during the dry season. In both habitats, unripe fruits were also continuous with a peak in September, while ripe fruits showed a peak in December and January in low-terrace and high-terrace forests, respectively, during the rainy season. Our findings show that flowering was continuous during the evaluated period, while fruiting increased during the rainy season associated with a greater number of days with precipitation. Full article
Show Figures

Figure 1

10 pages, 3028 KiB  
Article
Plywood Made from Plasma-Treated Veneers: Investigation of Performance Differences between Plasma-Pretreated and Untreated Beech Veneers at Comparable Melamine Resin Load
by Richard Wascher, Georg Avramidis and Wolfgang Viöl
Forests 2021, 12(10), 1423; https://doi.org/10.3390/f12101423 - 18 Oct 2021
Cited by 2 | Viewed by 1477
Abstract
In this study, the dimensional stability and mechanical properties of plywood made from untreated and plasma-pretreated beech veneers were compared. The wood veneers used (native and thermally modified) were impregnated with melamine resin in a simple dipping process prior to plywood production. The [...] Read more.
In this study, the dimensional stability and mechanical properties of plywood made from untreated and plasma-pretreated beech veneers were compared. The wood veneers used (native and thermally modified) were impregnated with melamine resin in a simple dipping process prior to plywood production. The duration of the impregnation process was adjusted to give the same melamine resin loading for the different veneer types, with the plasma-pretreated veneers requiring only a fraction of the impregnation time compared with non-plasma-pretreated veneers. With comparable melamine loading, testing of the mechanical properties of the plywood for the different specimen collectives showed significant differences in some cases with respect to compressive strength, bending strength and tensile strength (with the associated moduli of elasticity). For example, it was shown that plywood made from plasma-pretreated native beech veneers shows an increase in bending strength of about 8%, and from plasma-pretreated and thermally modified beech veneers, there is an increase of about 10% compared to the reference. Full article
(This article belongs to the Section Wood Science and Forest Products)
Show Figures

Figure 1

15 pages, 3717 KiB  
Article
Effects of Intercropping on Fractal Dimension and Physicochemical Properties of Soil in Karst Areas
by Qinqin Xu, Kangning Xiong and Yongkuan Chi
Forests 2021, 12(10), 1422; https://doi.org/10.3390/f12101422 - 18 Oct 2021
Cited by 12 | Viewed by 1860
Abstract
Suitable soil structure and nutrient security are important for plant growth and development. The fractal dimension of soil, along with the distribution of physical and chemical properties and their interactions, plays an important role in studying the stability of soil structures and water [...] Read more.
Suitable soil structure and nutrient security are important for plant growth and development. The fractal dimension of soil, along with the distribution of physical and chemical properties and their interactions, plays an important role in studying the stability of soil structures and water and fertilizer cycles. As a sustainable management model, intercropping has positive benefits for erosion control, the spatial optimization of resources, and improving system productivity. The effects of four intercropping methods on the fractal dimension and physicochemical properties of soil were investigated by intercropping Salvia miltiorrhiza with forage and S. miltiorrhiza with forest under typical karst rock desertification habitats in Guizhou. The results showed that the soil nutrient content when intercropping was significantly higher than that of monoculture. The organic carbon content of soil grown under forest is higher than other treatments, and there was a non-significant change in soil water content when intercropping compared with monoculture. The soil fine-grained matter when intercropping was significantly higher than that of monoculture, while the soil fractal dimension showed a tendency to become larger with an increase in fine-grained matter. Intercropping planting, due to its component types and spatial and temporal configurations, leads to differences in soil water and fertilizer interactions, which can be combined with other ecological restoration measures to optimize the composite model and jointly promote the restoration and development of ecologically fragile areas. Full article
(This article belongs to the Section Forest Soil)
Show Figures

Figure 1

17 pages, 11496 KiB  
Article
The Impact of Air Pollution on the Growth of Scots Pine Stands in Poland on the Basis of Dendrochronological Analyses
by Longina Chojnacka-Ożga and Wojciech Ożga
Forests 2021, 12(10), 1421; https://doi.org/10.3390/f12101421 - 18 Oct 2021
Cited by 5 | Viewed by 4164
Abstract
The aim of this study was to evaluate Scots pine stand degradation caused by the pollutants emitted from Zakłądy Azotowe Puławy, one of the biggest polluters of the environment in Poland for over 25 years (1966–1990). To assess the pollution stress in trees, [...] Read more.
The aim of this study was to evaluate Scots pine stand degradation caused by the pollutants emitted from Zakłądy Azotowe Puławy, one of the biggest polluters of the environment in Poland for over 25 years (1966–1990). To assess the pollution stress in trees, we chose the dendrochronological analysis We outlined three directions for our research: (i) the spatio-temporal distribution of the growth response of trees to the stress associated with air pollution; (ii) the direct and indirect effects of air pollution which may have influenced the growth response of trees; and (iii) the role of local factors, both environmental and technological, in shaping the growth response of trees. Eight Scots pine stands were selected for study, seven plots located in different damage zones and a reference plot in an undamaged stand. We found that pollutant emission caused disturbances of incremental dynamics and long-term strong reduction of growth. A significant decrease in growth was observed for the majority of investigated trees (75%) from 1966 (start of factory) to the end of the 1990s. The zone of destruction extended primarily in easterly and southern directions, from the pollution source, associated with the prevailing winds of the region. At the end of the 1990s, the decreasing trend stopped and the wider tree-rings could be observed. This situation was related to a radical reduction in ammonia emissions and an improvement in environmental conditions. However, the growth of damaged trees due to the weakened health condition is lower than the growth of Scots pine on the reference plot and trees are more sensitive to stressful climatic conditions, especially to drought. Full article
Show Figures

Figure 1

14 pages, 2795 KiB  
Article
Color Change and Physical-Mechanical Properties of Polystyrene-Impregnated Glulam from Three Tropical Fast-Growing Wood Species
by Yusuf Sudo Hadi, Dede Hermawan, Ignasia Maria Sulastiningsih, Efrida Basri, Gustan Pari, Rohmah Pari and Imam Busyra Abdillah
Forests 2021, 12(10), 1420; https://doi.org/10.3390/f12101420 - 18 Oct 2021
Cited by 7 | Viewed by 1944
Abstract
The aims of this work were to determine the color change and physical–mechanical properties of polystyrene glulam from three tropical wood species. Wood laminas were cut from logs harvested from a young plantation forest of manii (Maesopsis eminii), mangium (Acacia [...] Read more.
The aims of this work were to determine the color change and physical–mechanical properties of polystyrene glulam from three tropical wood species. Wood laminas were cut from logs harvested from a young plantation forest of manii (Maesopsis eminii), mangium (Acacia mangium), and rubber-wood (Hevea brasiliensis). The laminas were impregnated with monomer styrene that was polymerized using potassium peroxy-disulfate as a catalyst and heat. Three-layer glulam was constructed from the polystyrene laminas, using isocyanate glue and cold press. For comparison purposes, three-layer untreated glulam and solid wood samples were prepared. The results showed that the color change of polystyrene glulam was very small compared with untreated glulam. Polystyrene glulam had the highest density, while the density of untreated glulam did not differ from that of the solid wood. The moisture content of all products was matched to the environment, and fulfilled the Japanese standard. Compared with both types of glulams, solid wood had lower values for modulus of rupture (MOR), modulus of elasticity (MOE), and hardness, but higher shear strength. Meanwhile, polystyrene glulam had lower values for MOR and MOE, equal shear strength and wood failure, and higher hardness than the untreated glulam. All glulams had very little delamination in the hot water test. Only rubber-wood glulams fulfilled JAS 234-2003 for MOR, MOE, shear strength, and delamination. To obtain adequate physical–mechanical properties of glulams, medium-density wood is recommended for glulam manufacturing. Full article
(This article belongs to the Section Wood Science and Forest Products)
Show Figures

Figure 1

11 pages, 4438 KiB  
Article
Surface Detection of Solid Wood Defects Based on SSD Improved with ResNet
by Yutu Yang, Honghong Wang, Dong Jiang and Zhongkang Hu
Forests 2021, 12(10), 1419; https://doi.org/10.3390/f12101419 - 18 Oct 2021
Cited by 23 | Viewed by 2949
Abstract
Due to the lack of forest resources in China and the low detection efficiency of wood surface defects, the output of solid wood panels is not high. Therefore, this paper proposes a method for detecting surface defects of solid wood panels based on [...] Read more.
Due to the lack of forest resources in China and the low detection efficiency of wood surface defects, the output of solid wood panels is not high. Therefore, this paper proposes a method for detecting surface defects of solid wood panels based on a Single Shot MultiBox Detector algorithm (SSD) to detect typical wood surface defects. The wood panel images are acquired by an independently designed image acquisition system. The SSD model included the first five layers of the VGG16 network, the SSD feature mapping layer, the feature detection layer, and the Non-Maximum Suppression (NMS) module. We used TensorFlow to train the network and further improved it on the basis of the SSD network structure. As the basic network part of the improved SSD model, the deep residual network (ResNet) replaced the VGG network part of the original SSD network to optimize the input features of the regression and classification tasks of the predicted bounding box. The solid wood panels selected in this paper are Chinese fir and pine. The defects include live knots, dead knots, decay, mildew, cracks, and pinholes. A total of more than 5000 samples were collected, and the data set was expanded to 100,000 through data enhancement methods. After using the improved SSD model, the average detection accuracy of the defects we obtained was 89.7%, and the average detection time was 90 ms. Both the detection accuracy and the detection speed were improved. Full article
(This article belongs to the Special Issue Wood Production and Promotion)
Show Figures

Figure 1

19 pages, 1301 KiB  
Article
Microbial Diversity and Ecosystem Functioning in Deadwood of Black Pine of a Temperate Forest
by Roberta Pastorelli, Alessandro Paletto, Alessandro Elio Agnelli, Alessandra Lagomarsino and Isabella De Meo
Forests 2021, 12(10), 1418; https://doi.org/10.3390/f12101418 - 18 Oct 2021
Cited by 12 | Viewed by 2287
Abstract
The present study provides a deeper insight on variations of microbial abundance and community composition concerning specific environmental parameters related to deadwood decay, focusing on a mesocosm experiment conducted with deadwood samples from black pine of different decay classes. The chemical properties and [...] Read more.
The present study provides a deeper insight on variations of microbial abundance and community composition concerning specific environmental parameters related to deadwood decay, focusing on a mesocosm experiment conducted with deadwood samples from black pine of different decay classes. The chemical properties and microbial communities of deadwood changed over time. The total carbon percentage remained constant in the first stage of decomposition, showing a significant increase in the last decay class. The percentage of total nitrogen and the abundances of nifH harbouring bacteria significantly increased as decomposition advanced, suggesting N wood-enrichment by microbial N immobilization and/or N2-fixation. The pH slightly decreased during decomposition and significantly correlated with fungal abundance. CO2 production was higher in the last decay class 5 and positively correlated with bacterial abundance. Production of CH4 was registered in one sample of decay class 3, which correlates with the highest abundance of methanogenic archaea that probably belonged to Methanobrevibacter genus. N2O consumption increased along decomposition progress, indicating a complete reduction of nitrate compounds to N2 via denitrification, as proved by the highest nosZ gene copy number in decay class 5. Conversely, our results highlighted a low involvement of nitrifying communities in deadwood decomposition. Full article
Show Figures

Figure 1

13 pages, 2966 KiB  
Article
Opposite Tree-Tree Interactions Jointly Drive the Natural Fir Treeline Population on the Southeastern Tibetan Plateau
by Yafeng Wang, Qing Mao, Ping Ren and Shalik Ram Sigdel
Forests 2021, 12(10), 1417; https://doi.org/10.3390/f12101417 - 18 Oct 2021
Cited by 7 | Viewed by 2199
Abstract
The long-term stability of alpine treeline positions and increased stem density are frequently reported by recent studies; however, whether a denser treeline forest is relevant to competitive tree–tree interactions remain unclear. Herein, we mapped and surveyed individual trees in two undisturbed Smith fir [...] Read more.
The long-term stability of alpine treeline positions and increased stem density are frequently reported by recent studies; however, whether a denser treeline forest is relevant to competitive tree–tree interactions remain unclear. Herein, we mapped and surveyed individual trees in two undisturbed Smith fir (Abies georgei var. smithii) treeline plots (with a size: 30 m × 200 m; plot NE1: 4477 m, NE2: 4451 m) near Ranwu Lake (RW) on the southeastern Tibetan Plateau. The surface pattern method and spatial point pattern analysis were used to detect the spatial distribution patterns of three size classes (seedlings, juveniles, adults) and spatial associations between the pairwise size classes. We also compared our results to the spatial patterns of the five other treeline forests (Deqin, Linzhi, Changdu, Yushu, Aba) reported from the Tibetan Plateau. Young trees dominated the two fir treeline plots. Both positive and negative spatial autocorrelations for all of the trees were detected in two study plots. Intraspecific facilitation and competition coexisted at the fir treelines in three forest regions (RW, Linzhi, Aba) characterized by a mild moist climate, whereas intraspecific facilitation dominated the other three forest regions (Changdu, Deqin, Yushu), which featured seasonal climatic stress or high disturbance pressure. Thus, increased stem density at alpine treeline can be linked to competitive interactions in relatively favorable environmental conditions. Overall, the spatial patterns of the treeline population are mainly shaped by the combination of thermal and moisture conditions and are also modulated by non-climatic variables (e.g., disturbance history and microtopography). Full article
(This article belongs to the Special Issue Alpine Treeline Dynamics in the Anthropocene)
Show Figures

Figure 1

18 pages, 5826 KiB  
Article
Pollen Competition and Paternal Contribution during Artificially Controlled Pollination of Black Locust (Robinia pseudoacacia L.) without Castration
by Yuhan Sun, Ruiyang Hu, Li Dong, Xiuyu Li, Zijie Zhang, Qi Guo, Sen Cao, Jiankang Li, Peiyao Han, Chao Han, Saleem Uddin, Cui Long, Yingming Fan and Yun Li
Forests 2021, 12(10), 1416; https://doi.org/10.3390/f12101416 - 17 Oct 2021
Cited by 2 | Viewed by 1510
Abstract
(1) Background: Considering the serious damage caused by castration and the extremely high outcrossing rate in nature, we hypothesized that artificial controlled pollination of black locust without castration could be conducted for hybridization breeding. (2) Methods: The study conducted controlled pollination on 20 [...] Read more.
(1) Background: Considering the serious damage caused by castration and the extremely high outcrossing rate in nature, we hypothesized that artificial controlled pollination of black locust without castration could be conducted for hybridization breeding. (2) Methods: The study conducted controlled pollination on 20 mating combinations of black locust without castration using a single or mixed male parent. Offspring of different developmental stages and the leaves of parents were collected to extract DNA and perform paternity analysis using SSR molecular markers. (3) Results: The contribution rate of each male parent differed according to developmental stage after pollination using different pollens mixed in equal proportions. There were significant correlations between the genetic similarity between each male parent and female parent and contribution rate of each male parent at three different developmental stages after pollination. (4) Conclusions: The composition of offspring pollen donors showed no bias toward selfing or outcrossing when artificially pollinated without castration. Hybrid breeding of black locust by artificially controlled pollination without castration may not be feasible, given that our manual method resulted in a large number of abortive and abnormal offspring. Introduction of honeybees in a limited space to conduct controlled pollination of black locust for hybrid breeding may be feasible. Full article
(This article belongs to the Section Genetics and Molecular Biology)
Show Figures

Figure 1

11 pages, 3508 KiB  
Article
Testing the Performance of Some Competition Indices against Experimental Data and Outputs of Spatially Explicit Simulation Models
by Vladimir Shanin, Hannu Hökkä and Pavel Grabarnik
Forests 2021, 12(10), 1415; https://doi.org/10.3390/f12101415 - 16 Oct 2021
Cited by 2 | Viewed by 2548
Abstract
Three competition indices were tested against experimental data on the growth of individual trees in mapped forest stands and outputs of spatially explicit, process-based models of competition. The comparison showed the fundamental importance of taking into account the spatial structure of stands and, [...] Read more.
Three competition indices were tested against experimental data on the growth of individual trees in mapped forest stands and outputs of spatially explicit, process-based models of competition. The comparison showed the fundamental importance of taking into account the spatial structure of stands and, particularly, the relative spatial locations of individual trees (spatial asymmetry) when calculating the competition between trees. Although none of the competition indices are able to take into account the specific processes affecting the development of individual trees, these indices can be used in forest dynamics modeling as a simplified representation of competition between trees for resources. Full article
(This article belongs to the Special Issue Simulation Models of the Dynamics of Forest Ecosystems)
Show Figures

Figure 1

15 pages, 2846 KiB  
Article
Effects of Strip Roads in a Pine Tree Stand (Pinus sylvestris L.) on the Diameter Growth and Pith Eccentricity of Trees Growing along Them
by Włodzimierz Stempski, Krzysztof Jabłoński and Jakub Jakubowski
Forests 2021, 12(10), 1414; https://doi.org/10.3390/f12101414 - 16 Oct 2021
Cited by 2 | Viewed by 1788
Abstract
Although skid roads are more and more commonly used in Poland, they are still quite often criticised due to a certain loss of wood volume and the impact on edge trees. In this context, the results of the research described in this article [...] Read more.
Although skid roads are more and more commonly used in Poland, they are still quite often criticised due to a certain loss of wood volume and the impact on edge trees. In this context, the results of the research described in this article can be used as a substantive contribution to discussions about strip roads. Research was carried out in a 42-year-old pine tree stand (Pinus sylvestris L.) in the Notecka Forest, where thinning had been performed and 2.5 and 3.5 m wide strip roads had been cut 10 years before. The analysis comprised two five-year periods recording diameter growth and pith eccentricity in trees growing at the distance zones of 0–1 m (adjacent trees), 2–4 m and 8–10 m (the control) away from the strip roads. The differences in growth and eccentricity between the different distance zones as well as the frequency of pith eccentricity in the N-W, S-W, N-E and S-E directions were assessed, related to the distance from the strip road and the measurement height. The measurements of the analysed traits were conducted on wood discs cut from the centres of two-metre-long sections on sample trees (12 trees in each distance zone). The trees growing directly beside the strip roads were statistically significantly thicker than those growing 8–10 m away, and in the case of the trees beside the narrower strip roads, in the second 5-year period, they were also thicker than the trees from the 2–4 m distance zone. The effect of the wider strip roads in the first growth period was also significant for the trees growing 3 m away from the strip road (their growth in this period was significantly greater than that of trees in the control zone). The research into tree-pith eccentricity showed no differences due to relative distance from the strip road. Furthermore, no statistically significant relationship between the distance of trees from the strip road, measurement height and frequency of tree-pith eccentricity to the N-W and S-W were found. Full article
(This article belongs to the Section Forest Operations and Engineering)
Show Figures

Figure 1

16 pages, 10686 KiB  
Article
Tree Species Mapping on Sentinel-2 Satellite Imagery with Weakly Supervised Classification and Object-Wise Sampling
by Svetlana Illarionova, Alexey Trekin, Vladimir Ignatiev and Ivan Oseledets
Forests 2021, 12(10), 1413; https://doi.org/10.3390/f12101413 - 16 Oct 2021
Cited by 17 | Viewed by 3287
Abstract
Information on forest composition, specifically tree types and their distribution, aids in timber stock calculation and can help to better understand the biodiversity in a particular region. Automatic satellite imagery analysis can significantly accelerate the process of tree type classification, which is traditionally [...] Read more.
Information on forest composition, specifically tree types and their distribution, aids in timber stock calculation and can help to better understand the biodiversity in a particular region. Automatic satellite imagery analysis can significantly accelerate the process of tree type classification, which is traditionally carried out by ground-based observation. Although computer vision methods have proven their efficiency in remote sensing tasks, specific challenges arise in forestry applications. The forest inventory data often contain the tree type composition but do not describe their spatial distribution within each individual stand. Therefore, some pixels can be assigned a wrong label in the semantic segmentation task if we consider each stand to be homogeneously populated by its dominant species. Another challenge is the spatial distribution of individual stands within the study area. Classes are usually imbalanced and distributed nonuniformly that makes sampling choice more critical. This study aims to enhance tree species classification based on a neural network approach providing automatic markup adjustment and improving sampling technique. For forest species markup adjustment, we propose using a weakly supervised learning approach based on the knowledge of dominant species content within each stand. We also propose substituting the commonly used CNN sampling approach with the object-wise one to reduce the effect of the spatial distribution of forest stands. We consider four species commonly found in Russian boreal forests: birch, aspen, pine, and spruce. We use imagery from the Sentinel-2 satellite, which has multiple bands (in the visible and infrared spectra) and a spatial resolution of up to 10 meters. A data set of images for Leningrad Oblast of Russia is used to assess the methods. We demonstrate how to modify the training strategy to outperform a basic CNN approach from F1-score 0.68 to 0.76. This approach is promising for future studies to obtain more specific information about stands composition even using incomplete data. Full article
Show Figures

Figure 1

32 pages, 4626 KiB  
Article
Fungi Detected in the Previous Year’s Leaf Petioles of Fraxinus excelsior and Their Antagonistic Potential against Hymenoscyphus fraxineus
by Tadeusz Kowalski and Piotr Bilański
Forests 2021, 12(10), 1412; https://doi.org/10.3390/f12101412 - 16 Oct 2021
Cited by 21 | Viewed by 3107
Abstract
Studies on fungal communities in the previous year’s leaf petioles of Fraxinus excelsior found in litter in five ash stands in southern Poland were made in 2017. Fungi were identified on the basis of isolation from 300 surface sterilized leaf petioles and by [...] Read more.
Studies on fungal communities in the previous year’s leaf petioles of Fraxinus excelsior found in litter in five ash stands in southern Poland were made in 2017. Fungi were identified on the basis of isolation from 300 surface sterilized leaf petioles and by in situ inventory of fruit bodies (on 600 petioles, in spring and autumn). Identification was based on morphology of colonies and fruit bodies, and sequencing of ITS region of the rRNA gene cluster. In total, 2832 isolates from 117 taxa (Ascomycota—100; Basidiomycota—15; Mucoromycota—2 taxa) were obtained with the isolation method. The most frequent taxa (with frequency >10%) were: Nemania serpens, Hymenoscyphus fraxineus, Alternaria sp. 1, Boeremia sp., Helotiales sp. 1, Epicoccum nigrum, Venturia fraxini, Fusarium sp., Fusarium lateritium, Nemania diffusa, Typhula sp. 2 (in descending order). In total, 45 taxa were detected with the in situ inventory method. Eleven taxa were classified as dominant: Hymenoscyphus fraxineus, Venturia fraxini, Leptosphaeria sp. 2, Cyathicula fraxinophila, Typhula sp. 2, Hypoderma rubi, Pyrenopeziza petiolaris, Cyathicula coronata, Hymenoscyphus scutula, Leptosphaeria sclerotioides and Hymenoscyphus caudatus. Among 202 leaf petioles colonized by H. fraxineus, 177 petioles also showed fructification of 26 other fungi. All the isolated saprotrophs were tested in dual-culture assay for antagonism to two strains of H. fraxineus. Three interaction types were observed: type A, mutual direct contact, when the two fungi meet along the contact line (occurred with 43.3% of test fungi); type B, with inhibition zone between colonies (with 46.9% of test fungi); type C, when the test fungus overgrows the colony of H. fraxineus (with 9.8% of test fungi). The possible contribution of the fungal saprotrophs in limiting of the expansion of H. fraxineus in ash leaf petioles, which may result in reduction in the inoculum of ash dieback causal agent, is discussed. Full article
(This article belongs to the Section Forest Health)
Show Figures

Figure 1

14 pages, 2194 KiB  
Article
Differential Responses of Soil Bacterial and Fungal Community to Short-Term Crop Tree Management in a Larix gmelinii Plantation
by Li Ji, Jiangbo Yu, Xingzhe Zhang, Yue Liu and Lixue Yang
Forests 2021, 12(10), 1411; https://doi.org/10.3390/f12101411 - 15 Oct 2021
Cited by 3 | Viewed by 1557
Abstract
Crop tree management (CTM) is a widely applicable silviculture technology that is used to improve the performance of individual trees. However, only little information is available about the effects of the CTM regime on the soil microbial community structure. We conducted a study [...] Read more.
Crop tree management (CTM) is a widely applicable silviculture technology that is used to improve the performance of individual trees. However, only little information is available about the effects of the CTM regime on the soil microbial community structure. We conducted a study to explore the effects of short-term (five years) CTM on the soil bacterial and fungal diversity, community composition, and structure in the 0–10 cm soil layer in a Larix gmelinii (Rupr.) Kuzen. plantation. We set out to investigate the differential response of bacterial and fungal communities to variations in soil properties mediated by short-term CTM. Compared with the control plots, the soil microbial biomass carbon and microbial biomass nitrogen in CTM increased significantly by 64.2% and 32.3%, respectively. CTM significantly promoted the content of soil organic carbon, dissolved organic carbon, and nitrate nitrogen, and reduced the content of dissolved organic nitrogen. CTM changed the Shannon and Simpson indices of soil fungi to a remarkable extent but had little effect on the α diversity of bacterial communities. The bacterial β diversity was more sensitive to CTM than fungi. The relative abundance of Verrucomicrobiae (the dominant class of soil bacteria) in CTM was significantly increased by 78.2%, while the relative abundance of Agaricomycetes (dominant class for soil fungi) was reduced by 43.3%. We observed a significantly increased number of unique OTUs for soil fungi in the CTM plots. Redundancy analysis showed that dissolved organic carbon, soil moisture, and total phosphorus content significantly affected the composition of bacterial communities, while soil dissolved organic nitrogen, C/N, and total phosphorus drove the high variation in fungal community composition. Overall, our results emphasize the divergent response of soil bacterial and fungal communities in Larix gmelinii plantations to short-term CTM. We must pay more attention to the functional role of soil microbiota in future forest management. Full article
(This article belongs to the Section Forest Soil)
Show Figures

Figure 1

9 pages, 1263 KiB  
Article
The Contribution of Roots, Mycorrhizal Hyphae, and Soil Free-Living Microbes to Soil Respiration and Its Temperature Sensitivity in a Larch Forest
by Naoki Makita, Roma Fujimoto and Azusa Tamura
Forests 2021, 12(10), 1410; https://doi.org/10.3390/f12101410 - 15 Oct 2021
Cited by 10 | Viewed by 2428
Abstract
Soil respiration plays a critical role in driving soil carbon (C) cycling in terrestrial forest ecosystems. However, evidence to demonstrate the response of roots, mycorrhizal hyphae, and soil free-living microbes of soil respiration and their temperature sensitivity (Q10) remains lacking. [...] Read more.
Soil respiration plays a critical role in driving soil carbon (C) cycling in terrestrial forest ecosystems. However, evidence to demonstrate the response of roots, mycorrhizal hyphae, and soil free-living microbes of soil respiration and their temperature sensitivity (Q10) remains lacking. Here, we used a root exclusion method to assess the contribution and response of root respiration (Rroot), mycorrhizal respiration (Rmyc), and (soil organic matter) SOM respiration (Rsom) to soil temperature in a larch forest. During the growing period, the contributions of Rroot, Rmyc, and Rsom to soil respiration were 42%, 6%, and 52%, respectively. The respiration rates of all components increased exponentially with increasing temperature. Based on these constitutive respiration rates with soil temperature, the Q10 values for Rroot, Rmyc, and Rsom were 3.84, 5.18, and 1.86, respectively. The results showed that the response to temperature change was different among roots, mycorrhizal hyphae, and microbes in the soil, while the temperature sensitivity of autotrophic respiration was higher than that of heterotrophic respiration. Importantly, the Rmyc at this site was extremely sensitive to temperature, although its overall emission was small. Mycorrhizal associations were identified as the key drivers of soil respiration and temperature sensitivity. A good understanding of the different soil CO2 efflux components will provide useful information for determining soil C fluxes and predicting soil C dynamics under changing environments. Full article
(This article belongs to the Special Issue Forest Soil Carbon and Climate Changes)
Show Figures

Figure 1

11 pages, 2124 KiB  
Article
Live Crown Ratio Models for Loblolly Pine (Pinus taeda) with Beta Regression
by Krishna P. Poudel, Samantha C. Avery and Joshua J. Granger
Forests 2021, 12(10), 1409; https://doi.org/10.3390/f12101409 - 15 Oct 2021
Cited by 4 | Viewed by 1771
Abstract
The growth and production potential of a tree depends on its crown dimensions as these are closely related to a tree’s photosynthetic capacity. However, tree crowns have been studied less compared to their main stems because of their lower market value and because [...] Read more.
The growth and production potential of a tree depends on its crown dimensions as these are closely related to a tree’s photosynthetic capacity. However, tree crowns have been studied less compared to their main stems because of their lower market value and because the measurement of crown dimensions, such as crown volume or surface area, is difficult. Frequently, an individual tree’s live crown ratio (LCR) is predicted by linear or nonlinear models that are a function of easy-to-measure dendrometric variables using ordinary least-squares techniques. Using the long-term data from established genetic and spacing trials, we developed and evaluated the predictive performance of three nonlinear models and introduced a new generalized linear model for predicting LCR. The nonlinear models were fit using exponential, Weibull, and Richards functions. The generalized linear model was based on beta regression. This resulted in a slightly smaller error than the other models in predicting the LCR of loblolly pine trees used in this study. Crown ratio is measured in percentage unit and should be modeled using generalized linear models that assume a beta distribution for error terms. Full article
(This article belongs to the Section Forest Ecology and Management)
Show Figures

Figure 1

15 pages, 4290 KiB  
Article
The Effect of Sucrose Supplementation on the Micropropagation of Salix viminalis L. Shoots in Semisolid Medium and Temporary Immersion Bioreactors
by Diego Gago, Saladina Vilavert, María Ángeles Bernal, Conchi Sánchez, Anxela Aldrey and Nieves Vidal
Forests 2021, 12(10), 1408; https://doi.org/10.3390/f12101408 - 15 Oct 2021
Cited by 12 | Viewed by 2280
Abstract
The effect of sucrose concentration on the micropropagation of axillary shoots of willow was investigated. The following factors were examined: the culture system (semisolid medium in glass jars versus liquid medium in temporary immersion bioreactors), the type of explant (apical and basal sections), [...] Read more.
The effect of sucrose concentration on the micropropagation of axillary shoots of willow was investigated. The following factors were examined: the culture system (semisolid medium in glass jars versus liquid medium in temporary immersion bioreactors), the type of explant (apical and basal sections), the frequency of immersion, and CO2 enrichment. Shoots and leaf growth were significantly higher in RITA® bioreactors than in the jars for all the sucrose treatments. Apical or basal sections of willow cultured in bioreactors under high light intensity (150 µmol m−2 s−1) and ventilated six times a day with CO2-enriched air were successfully proliferated without sucrose, whereas shoots cultured in jars did not proliferate well if sucrose concentration was 0.5% or lower. More roots were formed when sucrose was added to the medium. Shoots cultured in bioreactors were successfully acclimatized irrespective of the sucrose treatment and the root biomass when transferred to ex vitro conditions. This is the first report of photoautotrophic willow micropropagation, our results confirm the importance of proper gaseous exchange to attain autotrophy during in vitro propagation. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

18 pages, 3907 KiB  
Article
Strategic Wildfire Response Decision Support and the Risk Management Assistance Program
by David E. Calkin, Christopher D. O’Connor, Matthew P. Thompson and Richard D. Stratton
Forests 2021, 12(10), 1407; https://doi.org/10.3390/f12101407 - 15 Oct 2021
Cited by 12 | Viewed by 3005
Abstract
In 2016, the USDA Forest Service, the largest wildfire management organization in the world, initiated the risk management assistance (RMA) program to improve the quality of strategic decision-making on its largest and most complex wildfire events. RMA was designed to facilitate a more [...] Read more.
In 2016, the USDA Forest Service, the largest wildfire management organization in the world, initiated the risk management assistance (RMA) program to improve the quality of strategic decision-making on its largest and most complex wildfire events. RMA was designed to facilitate a more formal risk management process, including the use of the best available science and emerging research tools, evaluation of alternative strategies, consideration of the likelihood of achieving objectives, and analysis of tradeoffs across a diverse range of incident objectives. RMA engaged personnel from a range of disciplines within the wildfire management system to co-produce actionable science that met the needs of the highly complex incident decision-making environment while aiming to align with best practices in risk assessment, structured decision-making, and technology transfer. Over the four years that RMA has been in practice, the content, structure, and method of information delivery have evolved. Furthermore, the RMA program’s application domain has expanded from merely large incident support to incorporate pre-event assessment and training, post-fire review, organizational change, and system improvement. In this article, we describe the history of the RMA program to date, provide some details and references to the tools delivered, and provide several illustrative examples of RMA in action. We conclude with a discussion of past and ongoing program adaptations and of how this can inform ongoing change efforts and offer thoughts on future directions. Full article
(This article belongs to the Special Issue Decision Support System Development of Wildland Fire)
Show Figures

Figure 1

14 pages, 2121 KiB  
Article
Application of Models to Predict Stand Volume, Aboveground Biomass Accumulation, and Carbon Storage Capacity for a Konishii Fir (Cunninghamia konishii Hayata) Plantation in Central Taiwan
by Minhas Hussain, Zheng-Rong Lin, Tian-Ming Yen and Chih-Chuan Lin
Forests 2021, 12(10), 1406; https://doi.org/10.3390/f12101406 - 15 Oct 2021
Cited by 5 | Viewed by 2140
Abstract
Konishii fir (Cunninghamia konishii Hayata) is an important conifer in Taiwan. The purpose of this study was to predict stand volume (V), aboveground biomass accumulation (AGB), and aboveground carbon storage (AGCST) for a Konishii fir plantation. This study was located at the [...] Read more.
Konishii fir (Cunninghamia konishii Hayata) is an important conifer in Taiwan. The purpose of this study was to predict stand volume (V), aboveground biomass accumulation (AGB), and aboveground carbon storage (AGCST) for a Konishii fir plantation. This study was located at the Huisun Experimental Forest Station of Nantou County located in central Taiwan. Four sample plots, each with an area of 0.05 ha, were installed and surveyed from 29 June to 2 July 2020. Two models, the diameter distribution model (DDM) and allometric model (AM), were used to predict V, AGB, and AGCST. Each item predicted by these two models was compared by the paired sample t-test. We employed the Weibull function to quantify stand diameter distribution and this function can effectively quantify diameter distribution, because all plots passed the examination by the Kolmogorov–Smirnov test (non-significant). Therefore, the Weibull function was suitable for developing the DDM. The predicted V, AGB, and AGCST were 538.43 ± 140.52 m3 ha−1, 203.25 ± 52.79 Mg ha−1, and 100.85 ± 26.30 Mg ha−1 by DDM; and 555.90 ± 145.42 m3 ha−1, 209.10 ± 51.25 Mg ha−1, and 103.78 ± 25.51 Mg ha−1 by AM, respectively. Each item was insignificantly different between DDM and AM, indicating similarity in results for both predictions. Meanwhile, using DDM is advantageous, as it can provide more yield information in diameter classes; therefore, this approach was recommended for yield prediction of the Konishii fir plantation. Full article
Show Figures

Figure 1

9 pages, 1419 KiB  
Protocol
ρ-MtreeRing: A Graphical User Interface for X-ray Microdensity Analysis
by Miguel García-Hidalgo, Ángel M. García-Pedrero, Cristina Caetano-Sánchez, Marcos Gómez-España, Mario Lillo-Saavedra and José Miguel Olano
Forests 2021, 12(10), 1405; https://doi.org/10.3390/f12101405 - 15 Oct 2021
Cited by 5 | Viewed by 1968
Abstract
Wood microdensitometry provides an integrated measurement of inter and intra-annual changes in wood anatomy and lignification. Although it can be acquired through a wide array of techniques, X-ray-based techniques are still the standard. Conversion of a grayscale X-ray image to density and annual [...] Read more.
Wood microdensitometry provides an integrated measurement of inter and intra-annual changes in wood anatomy and lignification. Although it can be acquired through a wide array of techniques, X-ray-based techniques are still the standard. Conversion of a grayscale X-ray image to density and annual ring boundaries delimitation is performed through image analysis software. Proprietary software has dominated these applications, albeit Free Open Source Software (FOSS) has been developed recently. We present ρ-MtreeRing, a user-friendly FOSS that streamlines the entire microdensitometry analysis process through a graphical user interface based on Shiny R Software without any programming knowledge. We compared the results of this program with the most widely used commercial software (WinDendro), showing the validity of the results. ρ-MtreeRing can be personalized and developed by the microdensitometry research community. Full article
(This article belongs to the Section Wood Science and Forest Products)
Show Figures

Figure 1

23 pages, 1345 KiB  
Review
Melatonin in Plant Defense against Abiotic Stress
by Abdul Rehaman, Awdhesh Kumar Mishra, Asma Ferdose, Tasir S. Per, Mohd Hanief, Arif Tasleem Jan and Mohd Asgher
Forests 2021, 12(10), 1404; https://doi.org/10.3390/f12101404 - 15 Oct 2021
Cited by 28 | Viewed by 4083
Abstract
Abiotic stress adversely affects plant growth and metabolism and as such reduces plant productivity. Recognized as a major contributor in the production of reactive oxygen species (ROS), it hinders the growth of plants through induction of oxidative stress. Biostimulants such as melatonin have [...] Read more.
Abiotic stress adversely affects plant growth and metabolism and as such reduces plant productivity. Recognized as a major contributor in the production of reactive oxygen species (ROS), it hinders the growth of plants through induction of oxidative stress. Biostimulants such as melatonin have a multifunctional role, acting as a defense strategy in minimizing the effects of oxidative stress. Melatonin plays important role in plant processes ranging from seed germination to senescence, besides performing the function of a biostimulant in improving the plant’s productivity. In addition to its important role in the signaling cascade, melatonin acts as an antioxidant that helps in scavenging ROS, generated as part of different stresses among plants. The current study was undertaken to elaborate the synthesis and regulation of melatonin in plants, besides emphasizing its function under various abiotic stress namely, salt, temperature, herbicides, heavy metals, and drought. Additionally, a special consideration was put on the crosstalk of melatonin with phytohormones to overcome plant abiotic stress. Full article
(This article belongs to the Special Issue Water Balance and Plant Responses to Drought)
Show Figures

Figure 1

21 pages, 3501 KiB  
Article
Differential Response of Macrobenthic Abundance and Community Composition to Mangrove Vegetation
by Sin-He Pan, Chuan-Wen Ho, Chiao-Wen Lin, Shou-Chung Huang and Hsing-Juh Lin
Forests 2021, 12(10), 1403; https://doi.org/10.3390/f12101403 - 14 Oct 2021
Cited by 11 | Viewed by 2386
Abstract
The mass planting of mangroves has been proposed as a mitigation strategy to compensate for mangrove loss. However, the effects of mangrove vegetation on the abundance and community composition of macrobenthos remain controversial. The macrobenthic communities in four intact mangrove forests with different [...] Read more.
The mass planting of mangroves has been proposed as a mitigation strategy to compensate for mangrove loss. However, the effects of mangrove vegetation on the abundance and community composition of macrobenthos remain controversial. The macrobenthic communities in four intact mangrove forests with different conditions and the adjacent nonvegetated mudflats of two mangrove species with distinct stand structures on the western coast of Taiwan were examined. Some macrobenthic taxa occurred only in the mangroves, suggesting macrobenthic critical habitats. Seasonal shift in community composition was more pronounced in the mudflats than in the mangroves, possibly due to the rich food supply, low temperature, and shelter function provided by mangrove forests. However, crab density was always lower in the mangroves than in the mudflats. There was a negative relationship between the stem density of Kandelia obovata (S., L.) and infaunal density. The pneumatophore density of Avicennia marina (Forsk.) correlated negatively with epifaunal density. Our results show that the response of macrobenthic abundance and community composition to mangrove vegetation was inconsistent. We reason that mangroves are critical habitats for the macrobenthos in the mudflats. However, if mangrove tree density is high, we predict that the macrobenthic density will decrease. This suggests that at some intermediate level of mangrove tree density, where there are enough mangrove trees to harbor a macrobenthic community but not enough trees to significantly reduce this density, mangroves management can be optimally achieved to promote the presence of a diverse and dense macrobenthic community. Full article
Show Figures

Figure 1

15 pages, 7137 KiB  
Article
Recreation and Therapy in Urban Forests—The Potential Use of Sensory Garden Solutions
by Sandra Wajchman-Świtalska, Alina Zajadacz and Anna Lubarska
Forests 2021, 12(10), 1402; https://doi.org/10.3390/f12101402 - 14 Oct 2021
Cited by 11 | Viewed by 3867
Abstract
Urban forests are not only woodlands or groups of trees, but also individual trees, street trees, trees in parks, trees in derelict corners, and gardens. All of which are located in urban and peri-urban areas and diversify the landscape and provide a wide [...] Read more.
Urban forests are not only woodlands or groups of trees, but also individual trees, street trees, trees in parks, trees in derelict corners, and gardens. All of which are located in urban and peri-urban areas and diversify the landscape and provide a wide range of social benefits. Sensory gardens play a specific therapeutic and preventive role. Designing such gardens as a recreational infrastructure element can successfully enrich urban forests. Following the principles of universal design may provide enjoyment for all city-dwellers, with special attention given to the needs of individuals with disabilities. We studied 15 gardens and one sensory path located in various regions in Poland. The inventory was carried out on the basis of the features considered important in spatial orientation by blind and partially sighted people. The results showed that the solutions used were only partly adequate for the needs of selected users. We found neither tactile walking surface indicators (e.g., communication lines and terrain), spatial models, nor applications in mobile devices. However, these could be useful for all visitors. We confirmed that although problems with the use of forest tourist space are dependent on the type of disability, by implementing the idea of universal design for all elements of recreational infrastructure, forests may be accessible for all users. Full article
Show Figures

Figure 1

12 pages, 1427 KiB  
Article
Genetic Structure and Geographical Differentiation of Larix sibirica Ledeb. in the Urals
by Nikita Chertov, Yulia Vasilyeva, Andrei Zhulanov, Yulia Nechaeva, Svetlana Boronnikova and Ruslan Kalendar
Forests 2021, 12(10), 1401; https://doi.org/10.3390/f12101401 - 14 Oct 2021
Cited by 4 | Viewed by 1851
Abstract
The Ural Mountains and the West Eurasian Taiga forests are one of the most important centers of genetic diversity for Larix sibirica Ledeb. Forest fragmentation negatively impacts forest ecosystems, especially due to the impact of their intensive use on the effects of climate [...] Read more.
The Ural Mountains and the West Eurasian Taiga forests are one of the most important centers of genetic diversity for Larix sibirica Ledeb. Forest fragmentation negatively impacts forest ecosystems, especially due to the impact of their intensive use on the effects of climate change. For the preservation and rational use of forest genetic resources, it is necessary to carefully investigate the genetic diversity of the main forest-forming plant species. The Larix genus species are among the most widespread woody plants in the world. The Siberian larch (Larix sibirica, Pinaceae) is found in the forest, forest-tundra, tundra (Southern part), and forest-steppe zones of the North, Northeast, and partly East of the European part of Russia and in Western and Eastern Siberia; in the Urals, the Siberian larch is distributed fragmentarily. In this study, eight pairs of simple sequence repeat (SSR) primers were used to analyse the genetic diversity and population structure of 15 Siberian larch populations in the Urals. Natural populations in the Urals exhibit indicators of genetic diversity comparable to those of Siberia populations (expected heterozygosity, He = 0.623; expected number of alleles, Ne = 4017; observed heterozygosity, Ho = 0.461). Genetic structure analysis revealed that the examined populations are relatively highly differentiated (Fst = 0.089). Using various algorithms for determining the spatial genetic structure, the examined populations formed three groups according to geographical location. The data obtained are required for the development of species conservation and restoration programs, which are especially important in the Middle Urals, which is the region with strong forest fragmentation. Full article
(This article belongs to the Special Issue Biodiversity and Conservation of Forests)
Show Figures

Figure 1

13 pages, 1278 KiB  
Review
Thermally Modified Wood Exposed to Different Weathering Conditions: A Review
by Delfina Godinho, Solange de Oliveira Araújo, Teresa Quilhó, Teresa Diamantino and Jorge Gominho
Forests 2021, 12(10), 1400; https://doi.org/10.3390/f12101400 - 14 Oct 2021
Cited by 11 | Viewed by 3032
Abstract
Outdoor wood applications are exposed to several different biotic and abiotic factors, and for that reason, they require protection to increase their service life. Several technologies of wood protection are already commercialized. One of these technologies is thermal modification, which refers to the [...] Read more.
Outdoor wood applications are exposed to several different biotic and abiotic factors, and for that reason, they require protection to increase their service life. Several technologies of wood protection are already commercialized. One of these technologies is thermal modification, which refers to the structural, mechanical, and chemical transformations occurring in the lignocellulosic material when gradually heated up to specific temperature ranges. In the past few years, several researchers have undertaken weathering resistance evaluations on different wood species. Some cases have considered natural exposure in different countries with different climatic conditions, while others focused on artificial exposure under UV and xenon radiation tests. Most works evaluated the weathering effects on the chemical, mechanical and physical, and anatomical shifts compared to the original characteristics of the material. This review has established a considerable lack of studies in the bibliography focusing on abiotic factors, such as the industrial and maritime environment, or even isolated climatic factors such as salt spray (simulating maritime environments) or pollutant gases (simulating industrial environments). This lack of information can be an opportunity for future work. It could help to understand if thermally modified wood is or is not sensitive to pollutant gases or salinity, or to a combination of both. By knowing the degradation mechanisms caused by these factors, it will be possible to study other forms of protection. Full article
(This article belongs to the Special Issue Evaluation and Protection of Wood and Wood Products)
Show Figures

Figure 1

22 pages, 6190 KiB  
Article
Ecological Design and Construction Strategies through Life Cycle Assessment of Carbon Budget for Urban Parks in Korea
by Hye-Mi Park and Hyun-Kil Jo
Forests 2021, 12(10), 1399; https://doi.org/10.3390/f12101399 - 14 Oct 2021
Cited by 8 | Viewed by 2700
Abstract
Although urban parks sequester carbon by vegetation growth, they emit carbon due to materials production, transport, construction, management, demolition, and disposal throughout their life cycle. This study estimated the carbon budget of urban parks over their life cycle according to land cover type [...] Read more.
Although urban parks sequester carbon by vegetation growth, they emit carbon due to materials production, transport, construction, management, demolition, and disposal throughout their life cycle. This study estimated the carbon budget of urban parks over their life cycle according to land cover type and explored ecological design and construction strategies to maximize carbon reduction. After setting up the scope of the life cycle, the energy and material used for each stage were analyzed on the basis of field survey, design and construction details, and literature review of 30 study parks. The net carbon uptake per unit of park area averaged 8.51 kg/m2, with urban parks playing an important role as a source of carbon uptake to mitigate the climate change. This study suggested ecological design and construction strategies including the expansion of tree planting spaces through the minimization of grass and impervious areas, the minimization of changes to existing topography, and the utilization of local materials. As a result of applying these strategies to study parks, the net carbon uptake increased approximately 9.2 times. These study results are expected to be useful as information for the implementation of carbon-neutral policies and greenspace establishment projects. Full article
(This article belongs to the Special Issue Ecosystem Services and Disservices of Urban Forests)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop