EISSN : 19994907
Current Publisher: MDPI (10.3390)
Total articles ≅ 3,010
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Latest articles in this journal
Forests, Volume 10; doi:10.3390/f10100830
Abstract:Dark septate endophytes (DSEs) are known to help host plants survive drought stress; however, how DSEs enhance host plant drought resistance under water stress conditions remains unclear. The objective of this study was to inoculate Ormosia hosiei seedlings with a DSE strain (Acrocalymma vagum) to investigate the effects of DSE inoculation on root morphology, ultrastructure, and the endogenous hormone content under drought stress conditions and to elucidate the drought resistance mechanism involved in the DSE–host-plant association. The inoculated seedlings were grown under three different soil water conditions (well watered—75% field water capacity, moderate water—55% field water capacity, or low water—35% field water capacity) for 114 days. Fresh root weight, root volume, root surface area, root fork, and root tip number were significantly higher in inoculated seedlings than in noninoculated seedlings. Furthermore, the root architecture of the inoculated seedlings changed from herringbone branching to dichotomous branching. Mitochondria and other organelles in root cells of inoculated seedlings remained largely undamaged under water stress, whereas organelles in root cells of noninoculated seedlings were severely damaged. The abscisic acid (ABA) and indole-3-acetic acid (IAA) content and IAA/ABA ratio of inoculated seedlings were significantly higher than those of noninoculated seedlings, whereas the content of gibberellic acid (GA) and the ratios of GA/ABA, zeatin riboside (ZR)/ABA, and ZR/IAA in inoculated seedlings were lower than those of noninoculated seedlings. DSE inoculation could help plants adapt to a drought stress environment by altering root morphology, reducing ultrastructural damage, and influencing the balance of endogenous hormones, which could be of great significance for the cultivation and preservation of the O. hosiei tree.
Forests, Volume 10; doi:10.3390/f10100831
Abstract:The present work presents the development of a moose movement model to explore the value of wildlife mitigation structures and examine how hypothetical changes in land use patterns could alter wildlife habitats at landscape scales. Collisions between vehicles and animals pose a threat to humans and wildlife populations, the most dangerous collisions being with moose. Migrations of moose are generally predictable and habitat-dependent. Here, we use GIS-based simulations of moose movements to examine road-related habitat fragmentation around the main highways A1 and A2 in Lithuania. From forest data, we develop a moose habitat suitability map. Then, by running multiple simulation iterations, we generate potential moose pathways and statistically describe the most efficient potential long-range movement routes that are based on the principles of habitat utilization. Reflecting the probabilities of cross-highway moose movement, ranks are assigned to all 1 km highway segments, characterizing them in terms of their likelihood of moose movement, and thus identifying discrete migration corridors and highway crossing zones. Bottlenecks are identified through simulation, such as where sections of wildlife fencing end without highway crossing structures, thereby creating a ‘spillover’ effect, i.e., moose moving parallel to the highway, then crossing. The tested model has proven the prognostic capacity of the tool to foresee locations of moose-vehicle collisions with high accuracy, thus allowing it to be a valuable addition to the toolbox of highway planners.
Forests, Volume 10; doi:10.3390/f10100832
Abstract:Management of natural forests in Costa Rica allows timber extraction in so far as it is guaranteed that the logging activities comply with diverse Sustainability Principles, Criteria and Indicators (PCIs). These are hierarchical and complex systems used, ex-ante in the formulation and approval of the Management Plan but have not been used for ex-post evaluation of managed forests. Development of sustainability evaluation systems that include few criteria is highly recommended. In that sense, the choice experiments contribute to simplification of the initial system of decision making, complementing a complex system of PCIs that permits detailed analysis of the management units. In this study, a choice experiment was included in a Delphi application and 5 key variables were identified to evaluate the sustainability of managed natural forests. These variables are, in order of importance—technical, legal and administrative conditions; external financing conditions; production performance; costs of preparing the Management Plan; and payment mechanisms for environmental services. The definition of these variables confirms not only that the technical, legal and administrative conditions are critical for sustainability but also that they could reflect the type of governance involved in sustainability forest management.
Forests, Volume 10; doi:10.3390/f10100833
Abstract:Necromass has a relevant role to play in the carbon stock of forest ecosystems, especially with the increase of tree mortality due to climate change. Despite this importance, its quantification is often neglected in tropical forests. The objective of this study was to quantify the carbon storage in a secondary Atlantic Forest fragment in Viçosa, Minas Gerais, Brazil. Coarse Woody Debris (CWD), standing dead trees (snags), and litter were quantified in twenty 10 m x 50 m plots randomly positioned throughout the forest area (simple random sampling). Data were collected during 2015, from July to December. The CWD and snags volumes were determined by the Smalian method and by allometric equations, respectively. The necromass of these components was estimated by multiplying the volume by the apparent density at each decomposition classes. The litter necromass was estimated by the proportionality method and the average of the extrapolated estimates per hectare. The carbon stock of the three components was quantified by multiplying the necromass and the carbon wood content. The total volume of dead wood, including CWD and snag, was 23.6 ± 0.9 m3 ha−1, being produced mainly by the competition for resources, senescence, and anthropic and climatic disturbances. The total necromass was 16.3 ± 0.4 Mg ha−1. The total carbon stock in necromass was 7.3 ± 0.2 MgC ha−1. The CWD, snag and litter stocked 3.0 ± 0.1, 1.8 ± 0.1, and 2.5 ± 0.1 MgC ha−1, respectively. These results demonstrate that although necromass has a lower carbon stock compared to biomass, neglecting its quantification may lead to underestimation of the carbon balance of forest ecosystems and their potential to mitigate climate change.
Forests, Volume 10; doi:10.3390/f10100834
Abstract:Whitebark pine (Pinus albicaulis. Engelm.) is vulnerable to a number of threats including an introduced pathogen (Cronartium ribicola J.C. Fisch.), epidemic levels of native mountain pine beetle (Dendroctonus ponderosae Hopkins), fire suppression, and climate change. To describe the structure of whitebark pine populations in two national parks in the southern Cascades (Crater Lake, Oregon, USA (CRLA) and Lassen Volcanic, California, USA (LAVO) National Parks), we surveyed trees in 30 × 50 × 50 m plots in both parks. We used these plots to describe the extent of white pine blister rust (the disease caused by Cronartium ribicola), mountain pine beetle occurrence, and to elucidate factors influencing the presence of pests and pathogens, cone production, and canopy kill. In each plot, we recorded data related to tree health, including symptoms of blister rust and mountain pine beetle, and reproductive vigor (cone production). In both parks, encroachment from other species, particularly mountain hemlock (Tsuga mertensiana (Bong.) Carrière), was negatively associated with cone production. In CRLA, water stress was a good predictor of blister rust infection and cone production. For CRLA and LAVO, the presence of mountain pine beetle and blister rust was associated with higher canopy kill for whitebark pine. Lastly, we found evidence for a pest-pathogen interaction, mountain pine beetle attack was greater for trees that showed symptoms of blister rust infection in CRLA. Our results indicate that whitebark pine populations in the southern Cascade Range are experiencing moderate levels of blister rust infection compared with other sites across the species range, and that competition from shade-tolerant species may result in an additional threat to whitebark pine in both parks. We present our findings in the context of park management and situate them in range-wide and regional conservation strategies aimed at the protection and restoration of a declining species.
Forests, Volume 10; doi:10.3390/f10100825
Abstract:This research aimed to assess vegetation composition and the indicator species around water source areas of pine forest plantation. Data were collected through interview and vegetation survey. Vegetation communities were first compared using multi-response permutation procedure (MRPP) analysis. Indicator species analysis was then employed to determine the indicator species for each condition by considering historical data from the interview. Canonical correspondence analysis (CCA) and simple correlation analysis were also included. The result showed significant differences in species composition between water source areas in Watujali (lower low flow) and Silengkong (higher low flow) catchments, indicated by T = −5.104, p = 0.000. Pinus merkusii was dominant in Watujali (important value = 78%, D′ = 0.62) compared to Silengkong (important value = 41%, D' = 0.21), and in becoming an indicator species (value = 52.1, p = 0.042) for Watujali. Meanwhile, Laportea sinuata, as the specific tree of water source areas, was an indicator for Silengkong (value = 29.4, p = 0.004). At a smaller level, indicator species differentiated the two catchments, even though they shared similar in D′ and H′. Among specific plants of water source areas, only Ficus septica was an indicator for Watujali (value = 29.4, p = 0.004), given its adaptability. Specific plants of water source areas, including Laportea sinuata, Coctus spicatus, and Calocassia gigantea, were significant indicators for Silengkong catchments, illustrated by 34.6, 35.9, and 33.0 of indicator values, respectively. These results also reflected the relationship among tree vegetation change, environmental features, and the growth of smaller species, as implied by both CCA and simple correlation. This finding could be used as basic information for early assessment of environmental change and environmental restoration efforts around water source areas on pine forest plantations. Repetition of this study is suggested to be carried out in other pine forest areas, as each region sometimes has its own specific native and natural species.
Forests, Volume 10; doi:10.3390/f10100826
Abstract:Research Highlights: A rigorous genome survey helped us to estimate the genomic characteristics, remove the DNA contamination, and determine the sequencing scheme of Betula platyphylla. Background and Objectives: B. platyphylla is a common tree species in northern China that has high economic and medicinal value. However, there is a lack of complete genomic information for this species, which severely constrains the progress of relevant research. The objective of this study was to survey the genome of B. platyphylla and determine the large-scale sequencing scheme of this species. Materials and Methods: Next-generation sequencing was used to survey the genome. The genome size, heterozygosity rate, and repetitive sequences were estimated by k-mer analysis. After preliminary genome assembly, sequence contamination was identified and filtered by sequence alignment. Finally, we obtained sterilized plantlets of B. platyphylla by plant tissue culture, which can be used for third-generation sequencing. Results: We estimated the genome size to be 432.9 Mb and the heterozygosity rate to be 1.22%, with repetitive sequences accounting for 62.2%. Bacterial contamination was observed in the leaves taken from the field, and most of the contaminants may be from the genus Mycobacterium. A total of 249,784 simple sequence repeat (SSR) loci were also identified in the B. platyphylla genome. Among the SSRs, only 11,326 can be used as candidates to distinguish the three Betula species. Conclusions: The B. platyphylla genome is complex and highly heterozygous and repetitive. Higher-depth third-generation sequencing may yield better assembly results. Sterilized plantlets can be used for sequencing to avoid contamination.
Forests, Volume 10; doi:10.3390/f10100829
Abstract:This paper presents a scaling approach for estimating sapwood area at the stand level using knowledge obtained for individual trees of five boreal species: Populus tremuloides (Michx.), Pinus contorta (Doug. ex Loud. var. latifolia Engelm.), Pinus banksiana (Lamb.), Picea mariana (Mill.) BSP, and Picea glauca (Moench) Voss. Previously developed allometric models for sapwood depth and diameter at breast height for individual tree species were used to build stand level sapwood area estimates as well as stand level leaf area estimates, in pure and mixed vascular vegetation stands. A stand’s vegetation heterogeneity is considered in the scaling approach by proposing regression models for each species. The new combined scaling approach drew strong linear correlations at the stand scale between sapwood area and leaf area using observations taken in mixed stands of Southern Alberta, Canada. This last outcome suggests a good linear relationship between stand sapwood area and stand leaf area. The accuracy of the results was tested by observing each regression model’s adequacy and by estimating the error propagated through the whole scaling process.
Forests, Volume 10; doi:10.3390/f10100824
Abstract:The availability and the quality of substrates are important drivers of macrofungal biogeography, and thus macrofungal species occurrence is potentially dependent on the availability of different substrates. However, few studies have explored the properties of macrofungal substrates and assessed the relationship between macrofungal diversity and substrate diversity at a landscape level. To address this issue, we conducted a landscape-scale survey of basidiocarp substrates in the Greater Mekong Subregion (GMS). A total of 957 macrofungal species distributed across 73 families and 189 genera were collected. Substrates of these macrofungi were categorized into four main groups (namely, litter, soil, root, and rare substrates) and referenced into 14 sub-substrate types (such as branches, leaves, and fruit). The results revealed that 50% of the observed macrofungal species were symbiotrophs living in ectomycorrhizal association with plant hosts, 30% were saprotrophs decomposing plant litter, 15% lived in soil organic matter, and 5% lived in rare substrates. The most abundant root symbiotic fungi were members of Russula, whereas most litter saprotrophic fungi belonged to Marasmius. Macrofungi commonly favored a single substrate. This specificity was not affected by changes in vegetation or climate. Less than 1% of macrofungi (e.g., Marasmius aff. maximus) could live on multiple substrates. Most of these unusual macrofungi were characterized as highly mobile and were generally found in successional areas. In secondary forests, our survey indicated that significant correlations exist between substrate preference and taxonomic diversity, reflected as higher substrate diversity generally accompanied by higher macrofungal diversity. In conclusion, substrate preference is an important factor driving macrofungal composition and distribution in the GMS. Macrofungi that thrive on multiple substrates constitute pioneer groups that have an important role in establishing macrofungal communities in new habitats. These observations have furthered our understanding of how substrate preferences could explain macrofungal biogeography.
Forests, Volume 10; doi:10.3390/f10100827
Abstract:Forest recreation can be successfully conducted for the purpose of psychological relaxation, as has been proven in previous scientific studies. During the winter in many countries, when snow cover occurs frequently, forest recreation (walking, relaxation, photography, etc.) is common. Nevertheless, whether forest therapy conducted in a forest environment with a snow cover will also have a positive effect on psychological indicators remains unknown. Furthermore, male subjects frequently participate in forest therapy experiments, whereas females are rarely involved. Thus, in this study, the effectuality of forest recreation during winter and with snow cover was tested on 32 young females. For these reasons, the experiment involved 15 min periods of relaxation in a forest environment or in an urban street environment, in addition to a pre-test under indoor conditions (randomized controlled study). Four psychological questionnaires Profile of Mood States (POMS), Positive and Negative Affect Schedule (PANAS), Restorative Outcome Scale (ROS), Subjective Vitality Scale (SVS)) were administered to participants before and after interventions. Results showed that participants’ levels of negative mood, as measured by different aspects of the POMS questionnaire (tension/anxiety, anger/hostility, depression/dejection, confusion, and fatigue), decreased after exposure to the forest environment. In contrast, both tension/anxiety and anger/hostility increased in the urban street environment. The indicator of negative affect from the PANAS questionnaire also increased after exposure to the urban street environment, whereas the indicator of positive affect based on PANAS was higher in the forest environment than in the urban street environment. Restorativeness and subjective vitality exhibited higher values after exposure to the forest environment in comparison to those from the control and pre-test. The changes in these indicators demonstrate that forest recreation in the snow during winter can significantly increase psychological relaxation in females, as well as show that recreation can be successfully conducted under these winter conditions.