Search

In the socio-ecological landscapes of tropical mountains, including the highly diverse Eastern Himalaya, fragments of natural forests have been traditionally managed as part of different agriculture systems. Recent studies have recognized their role as important biodiversity repositories outside protected areas. However, basic information on forest structure and composition of these forests outside protected areas is still limited in the Himalaya. In the current study, diversity, structure, composition, and regeneration status of non-protected forests were studied across 15 spatially different sites in the socio-ecological landscapes of Darjeeling-Sikkim, Eastern Himalaya, across an approximate elevation range of 500-2300 m above sea level. Quadrats (20 m × 5 m) were used to enumerate woody species in the study area. Enumeration of 156 quadrats (= 1.56 ha) resulted in a total of 249 woody species, of which species such as Schima wallichii, Alnus nepalensis, and Engelhardtia spicata were found to dominate the existing stand of trees. The vegetation structure of these forests was found to be almost comparable with that of protected forests, as assessed by prior studies in the same landscape. Species composition of woody plants in the study area were found to be primarily influenced by elevation. Assessment of regeneration patterns found the forests to have a high regeneration potential, however, the most dominant tree species of the area had relatively fewer saplings, indicating probable replacement of localized species of large trees by disturbance-adapted species. The current study adds to the literature on the structure and composition of non-protected forests in the tropical mountains. [ABSTRACT FROM AUTHOR]

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Assisted succession could enable long‐term restoration where successional trajectories stall due to competition from invasive plants. Many invasives are shade‐intolerant; therefore, interventions reducing light availability should suppress invasion and re‐establish successional processes. However, given how ubiquitous nonlinearities are in ecology, restoration success also depends on identifying critical system thresholds, for example invader abundances below which regeneration of desired species is possible. We report the successful use of assisted succession to restore a swamp forest invaded by Phalaris arundinacea (reed canarygrass; hereafter Phalaris), initiated by a high‐density planting of woody species to outcompete Phalaris by reducing light availability.We established five pre‐planting treatments in a Phalaris near‐monoculture in Wisconsin, USA: herbicide‐only, herbicide+plough, herbicide+burn, mow+herbicide and control. In 2003 we planted 22 tree and shrub species at high densities, then in 2019 we censused the site to: (1) screen for long‐term differences among treatments, (2) evaluate long‐term effects of our interventions on community composition and (3) characterize the critical thresholds that enable invader suppression and restoration success.Vegetation responses and light availability across our four pre‐planting invader removal treatments did not differ. Late fall glyphosate application suppressed Phalaris long enough that a dense canopy of native woody species could establish and eventually out‐shade it. Overstory tree and shrub densities of 0.071/m2 suppressed Phalaris to 50% cover, but, due to nonlinearities, much higher densities were needed to reduce light availability and thus Phalaris cover enough to shift the system from being invader‐dominated. Compositional similarities between juvenile woody species and the overstory suggest a long‐term restoration success.Synthesis and applications. Invasive species management and the restoration of target plant communities can be aided by assisting successional trajectories that have stalled. We document a restoration strategy for forests invaded by shade‐intolerant invaders that is both effective and economical, as only a simple site preparation and single planting effort is required. Establishing a dense canopy of woody species in this way can break the feedbacks maintaining invader dominance and re‐introduce feedbacks enabling long‐term ecosystem recovery. We also illustrate the value of identifying critical thresholds influencing the abundance and impact of key invasive species. [ABSTRACT FROM AUTHOR]

Global forests are increasingly lost to climate change, disturbance, and human management. Evaluating forests' capacities to regenerate and colonize new habitats has to start with the seed production of individual trees and how it depends on nutrient access. Studies on the linkage between reproduction and foliar nutrients are limited to a few locations and few species, due to the large investment needed for field measurements on both variables. We synthesized tree fecundity estimates from the Masting Inference and Forecasting (MASTIF) network with foliar nutrient concentrations from hyperspectral remote sensing at the National Ecological Observatory Network (NEON) across the contiguous United States. We evaluated the relationships between seed production and foliar nutrients for 56,544 tree‐years from 26 species at individual and community scales. We found a prevalent association between high foliar phosphorous (P) concentration and low individual seed production (ISP) across the continent. Within‐species coefficients to nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) are related to species differences in nutrient demand, with distinct biogeographic patterns. Community seed production (CSP) decreased four orders of magnitude from the lowest to the highest foliar P. This first continental‐scale study sheds light on the relationship between seed production and foliar nutrients, highlighting the potential of using combined Light Detection And Ranging (LiDAR) and hyperspectral remote sensing to evaluate forest regeneration. The fact that both ISP and CSP decline in the presence of high foliar P levels has immediate application in improving forest demographic and regeneration models by providing more realistic nutrient effects at multiple scales. [ABSTRACT FROM AUTHOR]

Rodents play a key role in forest regeneration by dispersing seeds and interspecific differences in seed preferences could have important consequences for forest growth. The White-footed Mouse (Peromyscus leucopus) and Deer Mouse (Peromyscus maniculatus gracilis) are 2 closely related species that can exploit Red Oak (Quercus rubra) acorns but may display different preference levels due to the high tannin concentration present in these acorns. Here we investigated how White-footed Mice and Deer Mice differ in their ability to exploit Red Oak acorns. We conducted a cafeteria-style experiment where we offered mice (n = 61) acorns of Red Oak and Bur Oak (Q. macrocarpa ; control seed with lower tannin levels) and video-recorded their preference and the acorn fate (consumed or cached). Using mixed-effects models, we found that both mouse species selected and consumed Bur Oak acorns at a high rate; however, White-footed Mice were 6.67 times more likely to select and consume Red Oak acorns than Deer Mice. Furthermore, White-footed Mice tended to cache Red Oak acorns near the surface where there is a higher chance of germination, while they usually consumed Bur Oak acorns. Our results suggest that Red Oaks have a better strategy for avoiding predation than Bur Oaks (i.e. high tannin levels leading to caching), and the strong interaction between the White-footed Mouse and Red Oak might be an important mechanism behind the current range expansion of both species in response to climate change. [ABSTRACT FROM AUTHOR]

The recovery of soil properties and the proper growth of natural tree regeneration are key elements for maintaining forest productivity after selective logging operations. This study was conducted on the soil properties and natural growth of two pioneer seedling species of alder and maple which were on skid trails in the mixed beech forests of northern Iran. To examine the long-term effects, we randomly selected six skid trails, with two replicates established for each of three time periods since last use (10, 20, and 30 years ago). Random plots 4 m × 10 m in size, three plots on each skid trail and six plots on areas without soil compaction (control), were selected. Measurements included the physical and chemical properties of the soil and the growth, and the architectural and qualitative characteristics of the seedlings. The results showed that all the soil properties of the 10- and 20-year-old skid trails were significantly different from the control area (except for the soil moisture in the 20-year-old skid trail). The 30-year-old skid trail showed values of other soil properties which were not significantly different from the control area, except for the amounts of organic matter and soil nitrogen, which was less than the control. The skid trails had a negative effect on all of the growth, qualitative, and architectural indices of seedlings. The characteristics of seedlings were related to soil characteristics and had the highest correlation with the soil penetration resistance (R-value from −0.41 to −0.63 for stem growth, p < 0.05; −0.57 to −0.90 for root growth, p < 0.01; and −0.76 to −0.86 for biomass, p < 0.01). The correlation coefficient between soil penetration resistance and the Dickson quality index of alder and maple seedlings was, respectively, −0.74 and −0.72, p < 0.01. The negative effect of soil compaction on root growth (−27.69% for alder seedlings and −28.08% for maple seedlings) was greater than on stem growth (−24.11% for alder seedlings and −16.27% for maple seedlings). The amount of growth, qualitative, and architectural indices of alder seedlings were higher than that of maple seedlings. Although alder is a better choice as compared to maple seedling in the initial year, the results of our study show that it is recommended to plant both alder and maple on skid trails after logging operations. [ABSTRACT FROM AUTHOR]

The shea tree (Vitellaria paradoxa C.F. Gaertn.) is an important tree species in agroforestry systems in West Africa and shea nuts constitute a fundamental resource for rural livelihoods in this area. This study investigated the sustainability and interactions in agroforestry systems of shea trees around the village Nakpalli in Northern Ghana. The focus of the study was the population structures and densities of shea trees on different land types, below-canopy microclimate and co-cultivation of yams (Dioscorea rotundata (Poir.) J. Miége) under shea tree canopies, and water stress of the trees in the driest season. Shea tree populations are overall well-conserved in this area, but Weibull-distributions of the tree populations and quantification of seedlings showed a lower tree density in both cultivated and fallowed lands, as compared to undisturbed bushlands. Although farmers may deliberately manage the density of larger trees, the low densities of seedlings and saplings indicate that intensified management practices, including shortened fallow periods and intentional clearing of land by fire before sowing, might negatively affect the long-term regeneration of the shea trees. Co-cultivation of yams below shea tree canopies allowed production of 11.5 t/ha as compared to 20.8 t/ha at open field conditions. The lower yields may have been caused by an almost 74% reduction of photosynthetically active radiation below canopies, relative to outside the canopies. Shea trees in the fields, fallows and bushlands had close-to-zero predawn leaf water potentials, indicating low water stress, even in the middle of the dry season. Thus, shea trees are both well-adapted and highly valued in this area, which underlines the importance of conserving this indigenous tree species in the agroforestry systems of northern Ghana. [ABSTRACT FROM AUTHOR]

Post‐disturbance forest management is known to impair biodiversity, including bird communities, but most studies focus on short‐term effects of salvage logging, without recognition of the cumulative, lasting impact of collective post‐disturbance silvicultural practices. We tracked bird community succession in a temperate pine forest from 5 to 19 years after wind disturbance in managed and unmanaged windthrow areas, covering the period from gap creation to early canopy regeneration and comparing it to nearby production forest unaffected by wind disturbance. Bird communities of unmanaged windthrow were consistently the richest in terms of bird abundance and richness. They hosted comparable forest bird diversity to unaffected production stands throughout the study period, as well as a substantial diversity of farmland birds. Managed and unmanaged windthrows followed two distinct successional pathways and did not converge. Despite the bird communities in both windthrows gradually resembling those found in undisturbed forests as the canopy regenerated, each type of windthrow and the unaffected production forest maintained distinct communities until the end of the study. Synthesis and applications. Restraining from any active post‐windthrow management sets bird succession on a distinct pathway, leading to unique and diverse bird communities. We advocate viewing natural disturbances as cost‐effective ecosystem restoration tools, provided no active management is implemented. Furthermore, we advise against using the term ‘salvage logging’ to refer to collective post‐disturbance silvicultural practices, as its varying interpretation may lead to growing confusion as the number of long‐term studies increase. [ABSTRACT FROM AUTHOR]

Assisted Natural Regeneration (ANR) is a set of restoration strategies and interventions primarily based on natural regeneration, aimed at accelerating succession and providing multiple benefits in degraded ecosystems and landscapes. These strategies have the potential to significantly contribute to global Forest and Landscape Restoration efforts. However, ANR faces challenges due to limited recognition, support, and formal integration into relevant sectors and restoration policies, particularly in tropical regions. The dearth of evidencebased syntheses further compounds these challenges. To address this gap, a bibliometric analysis of selected scientific publications on ANR (n = 208) from 1987 to 2023 was conducted, using Web of Science and Google Scholar databases. A systematic review was undertaken, using a subset of original research articles (n = 44), to synthesize published data on interventions, contexts, costs, and benefits of ANR and to identify major knowledge gaps. Analysis of bibliometric metadata revealed an increasing annual output of ANR publications in over 80 journals, encompassing various document types and authors from over 40 countries. Despite ANR's formal emergence in the Philippines, Brazil has taken the lead in both its research and implementation, and international collaboration in ANR research has grown. While ANR research focused mostly on ecosystem services and ecological outcomes, social aspects have been poorly studied. Diverse ANR interventions align not only with ecological restoration but also with integrated land management, biodiversity conservation, forest and landscape restoration, and forest management. The cost-effectiveness of ANR implementation, especially in restoration for carbon storage, exhibited considerable variability when compared to active tree planting, and varied with intervention types, time, land use history, and long-term costs. This synthesis provides critical insights and evidence to enhance the effective integration of ANR into restoration and reforestation programs and policies. [ABSTRACT FROM AUTHOR]

Monoculture of pine alters the soil fauna community structure, but forest farms, mixed with natural areas, are restoring the original vegetation to protect, the diversity and ecosystem functions. In restoration initiatives it is necessary to consider the soil fauna. Thus, the aim of this study was to investigate how the process of restoration of the soil community occurs over time in areas after pine harvesting. Areas in natural regeneration with 4 and 10 years, pine plantations adjacent to these areas (representing previous use), and areas of natural forest (reference) were evaluated, it was evaluated three areas per treatment, with six sampling points spaced 30 m apart, totalling 18 sampling points for each treatment (n = 18). Soil mesofauna and macrofauna were collected through soil monoliths and pitfall traps. The comparison of the statistical analysis was to check for changes in the soil fauna over time (4 and 10 years) compared with that observed in secondary forest areas. The study showed that, along the natural regeneration time (4 and 10 years), it was observed increments in the diversity and evenness of the soil community and a reduction in the dominance of groups like Formicidae and increases in the community structure complexity with the resurgence of micropredators/regulators (Collembola and Acari), litter transformers (Oligochaeta, Diplopoda, Blattodea, Coleoptera (Larva), Diptera (Larva) and Coleoptera) and predators (Pseudoscorpiones, Opiliones, Symphyla and Coleoptera) after 10 years of natural regeneration, the areas have already recovered groups with important ecosystem functions, but are not yet at the level of abundance, functional diversity and community structure of native forest areas. The 4‐ and 10‐year regeneration areas present major number of soil fauna groups of native forest (20 groups in regeneration areas and 17 in the native forest areas). Even so, the forest showed a major complexity of soil fauna community structure, evidenced by the diversity. This study contributes to the understanding of natural regeneration for soil fauna along a temporal gradient and these findings can guide the conservation of regional soil fauna diversity. [ABSTRACT FROM AUTHOR]

Natural native forests are rapidly being replaced by anthropogenic forests often with a strong presence of invasive alien plant species. Eucalypt species are widely planted worldwide, with Eucalyptus globulus plantations being particularly expressive in Portugal. Poor forestry practices often lead to the associated expansion of invasive species, such as Acacia dealbata. However, we still know relatively little about the functioning of anthropogenic forests, such as seed and pollen dispersal services. Here, we compared bird abundance and richness and the seed and pollen dispersal networks in both forest types. Anthropogenic forests presented lower bird abundance, and smaller, more simplified, and more random (abundance‐based) seed dispersal services than those of natural forests. Interestingly, the pollen dispersal network was more similar than the seed dispersal network for both forest types and dominated by opportunistic and neutral processes, given the absence of specialized nectarivorous. The proportion of birds transporting seeds decreased, while those carrying pollen significantly increased in the anthropogenic forest compared to the native forest. Our work highlights the impact of anthropogenic forests on bird abundance, with consequences for seed dispersal services and forest regeneration. [ABSTRACT FROM AUTHOR]

Downed woody debris is important for biodiversity, forest regeneration, and carbon, nutrient, and water cycling, and past studies have examined how the coarse fraction is affected by climate or harvesting. In a field study in Douglas-fir dominated forests, we expand existing knowledge by investigating the interacting effects of climate and harvesting on downed woody debris of all sizes. Across a 900-km long latitudinal gradient in British Columbia, we found that coarse woody debris (CWD, >7.5 cm diameter) in humid climates contained 700% greater carbon stocks, had 500% greater volume, and was more diverse than in arid climates. Pre- and post-harvest, small and fine woody debris comprised a higher proportion of total woody debris carbon stocks in arid than moist climates, especially after clearcutting and seed tree treatments. Harvesting generally decreased total CWD volume, but it was not depleted on any site. Harvesting substantially reduced the volume of large, highly decomposed CWD except at the two most arid sites, and losses of large CWD increased with increasing tree removal. These losses were accompanied by a pulse of fresh, small diameter CWD and SWD which are short-term organic nutrient sources but have less habitat value than larger pieces and contribute to fuel loads. Because CWD was less abundant in arid than humid mature forests, care must be taken on arid sites to avoid its depletion during harvesting, especially clearcutting, where future woody debris inputs will not occur for decades. [ABSTRACT FROM AUTHOR]

The persistence of plant populations depends crucially on successful regeneration. Yet, little is known about the effects of consecutive winter and spring frost events on the regeneration stage of trees from different seed sources, although this will partly determine the success of climate warming‐driven poleward range shifts. In a common garden experiment with European beech (Fagus sylvatica) seedlings from winter 2015/2016 to autumn 2017, we studied how simulated successive spring and winter frost events affect leaf‐out dates, growth performance, and survival rates of 1‐ to 2‐year‐old seedlings from provenances differing in climate at origin. We further investigated the combined effects of successive frost events. The first spring frost after germination led to a mortality rate up to 75%, resulting in reduced seedling numbers but better frost tolerance of the survivors, as reflected in a weaker impact of the following winter frost event in the survivors compared to the non‐acclimated control. Final plant height was most strongly reduced by the spring frost in the second year. The winter frost event delayed leaf‐out by up to 40 days, leading to severe growth impairment in 2017. Our results indicate partly successful frost acclimation and/or the selection of frost‐hardier individuals, because the negative growth effects of consecutive frost events did not add up after exposure to more than one event. Both mechanisms may help to increase the frost tolerance of beech offspring. Nevertheless, mortality after the first spring frost was high, and frost exposure generally caused growth reductions. Thus, achieving higher frost tolerance may not be sufficient for beech seedlings to overcome frost‐induced reductions in competitive strength caused by winter frost damage and delayed leaf enfolding. [ABSTRACT FROM AUTHOR]

Gaps are openings within tropical forest canopies created by natural or anthropogenic disturbances. Important aspects of gap dynamics that are not well understood include how gaps close over time and their potential for contagiousness, indicating whether the presence of gaps may or may not induce the creation of new gaps. This is especially important when we consider disturbances from selective logging activities in rainforests, which take away large trees of high commercial value and leave behind a forest full of gaps. The goal of this study was to quantify and understand how gaps open and close over time within tropical rainforests using a time series of airborne LiDAR data, attributing observed processes to gap types and origins. For this purpose, the Jamari National Forest located in the Brazilian Amazon was chosen as the study area because of the unique availability of multi-temporal small-footprint airborne LiDAR data covering the time period of 2011–2017 with five data acquisitions, alongside the geolocation of trees that were felled by selective logging activities. We found an increased likelihood of natural new gaps opening closer to pre-existing gaps associated with felled tree locations (<20 m distance) rather than farther away from them, suggesting that small-scale disturbances caused by logging, even at a low intensity, may cause a legacy effect of increased mortality over six years after logging due to gap contagiousness. Moreover, gaps were closed at similar annual rates by vertical and lateral ingrowth (16.7% yr−1) and about 90% of the original gap area was closed at six years post-disturbance. Therefore, the relative contribution of lateral and vertical growth for gap closure was similar when consolidated over time. We highlight that aboveground biomass or carbon density of logged forests can be overestimated if considering only top of the canopy height metrics due to fast lateral ingrowth of neighboring trees, especially in the first two years of regeneration where 26% of gaps were closed solely by lateral ingrowth, which would not translate to 26% of regeneration of forest biomass. Trees inside gaps grew 2.2 times faster (1.5 m yr−1) than trees at the surrounding non-gap canopy (0.7 m yr−1). Our study brings new insights into the processes of both the opening and closure of forest gaps within tropical forests and the importance of considering gap types and origins in this analysis. Moreover, it demonstrates the capability of airborne LiDAR multi-temporal data in effectively characterizing the impacts of forest degradation and subsequent recovery. [ABSTRACT FROM AUTHOR]

Restoration of root hemiparasite trees, such as Hawaiʻi's endemic Santalum species (ʻiliahi), may benefit from underplanting in stands of suitable hosts like the nitrogen‐fixing native tree, Acacia koa (koa). At a pasture site on Hawaiʻi Island previously reforested with koa, we underplanted seedlings of the island‐endemic sandalwood species, Santalum paniculatum, to examine the tradeoff between access to an established root network (distance to the nearest koa tree) under variable overstory shading (8.8–90.1% canopy openness range) during regeneration establishment. We hypothesized that there is an optimal parasite–host spacing and canopy openness that balance parasitic resource transfer with light availability. ʻIliahi seedling survival was 96% with no survival treatment differences. 'Iliahi seedling growth was positively related to canopy openness but negatively related to the distance to the nearest koa tree, and the slope of these relationships increased over time. Leaf photosynthetic light compensation points, light saturation points, and stomatal density mostly followed similar trends as growth. These results demonstrate that 'iliahi can be successfully underplanted in an established koa stand, which benefits 'iliahi plantings and contributes to diversifying initial restoration and reforestation plantings. There appears to be a significant tradeoff in planting distance between benefits from and competition with the host; however, the improvement in growth with increased canopy openness appeared to be much greater than the effect of planting distance. Underplanting into an established host stand with sufficient canopy openness can help restore functionally compatible and abundant 'iliahi regeneration into forests. [ABSTRACT FROM AUTHOR]

Worldwide, the implementation of forest management guidelines has tried to mimic natural forest dynamics. The Oliver forest stand dynamics model has been successful in bridging natural forest dynamics associated with the disturbances of various spatial scales and silviculture also related to various spatial scales of management. However, the application of this model (and others) is restricted to tall forests.We claim here that the general research and commercial interest bias towards tall tree species has permeated silviculture and forest management, and that both the stand dynamics of short‐stature tree species and their treatment have remained largely unexplored and unknown.Using one short‐stature tree species, Nothofagus antarctica, as a model system, we show that this species indeed follows a stand dynamic different from other tall Nothofagus‐dominated forests in southern South America. This species forms short, mature, even‐aged stands without large canopy gaps that promote tree regeneration. With this in mind, we propose a conceptual ecology‐based silvicultural guideline focusing on the creation of strip cuts or gaps along with topsoil scarification to ensure regeneration and forest reorganization after disturbances.Policy implications. The acknowledgement that short‐stature tree species follow a stand dynamic different from tall tree species necessarily implies that they must be managed differently. This recognition, along with the implementation of ecology‐based silvicultural recommendations, represents strong arguments to make modifications to forest legislation that, together, must be aimed at conservation and sustainable forest management. [ABSTRACT FROM AUTHOR]

Natural disturbances are important drivers of forest dynamics, and canopy gaps are their fingerprints in forest ecosystems. Gaps form and persist because of the interplay of tree mortality and regeneration. They can have long‐lasting impacts on ecosystems, yet the temporal dynamics of gap formation and closure remains poorly quantified.We analysed 11,331 canopy gaps and their changes through time across 3999 ha of unmanaged temperate mountain forests at Berchtesgaden National Park (Germany). We assessed gap formation and closure using three repeat lidar acquisitions between 2009 and 2021, analysing canopy height changes at 1 m horizontal resolution. Our objective was to determine the dominant mode of gap formation, distinguishing the creation of new gaps from the expansion of existing ones. Additionally, we studied the rate of gap closure, considering closure from tree regeneration and lateral crown expansion.Gap formation was primarily driven by gap expansion rather than the initiation of new gaps. Gap expansion accounted for 81.3% of gap formation, although new gaps were on average twice as large as gap expansions. Only 1.4% of gaps did not expand over the 12‐year study period, and Norway spruce forests had the highest rate of gap expansion.Overall, gap closure rate (0.74 ha 100 ha−1 year−1) was higher than gap formation (0.58 ha 100 ha−1 year−1) in our study system. Ingrowth of the regenerating tree cohort was the primary mode of gap closure, with lateral crown expansion accounting for 20% of all gap area closed. Mixed‐species stands had the highest rate of gap closure, and gaps <0.1 ha closed faster than larger gaps.Synthesis. While canopy openings are generally small in the European Alps, we show that they keep growing over multiple years, underlining that gap expansion is an important driver of temperate forest dynamics. Canopy gaps closed faster than they were created, highlighting the resilience of European mountain forests to natural disturbances. However, as disturbances are projected to increase under climate change, this resilience might be challenged in the future, requiring a continuous monitoring of gap dynamics as an important early warning indicator of forest change. [ABSTRACT FROM AUTHOR]

Forests provide essential ecosystem services that range from the production of timber to the mitigation of natural hazards. Rapid environmental changes, such as climate warming or the intensification of disturbance regimes, threaten forests and endanger forest ecosystem services. In light of these challenges, it is essential to understand forests' demographic processes of regeneration, growth, and mortality and their relationship with environmental conditions. Specifically, understanding the regeneration process in present‐day forests is crucial since it lays the foundation for the structure of future forests and their tree species composition. We used Swiss National Forest Inventory (NFI) data covering vast bio‐geographic gradients over four decades to achieve this understanding. Trees that reached a diameter at breast height of 12 cm between two consecutive NFI campaigns were used to determine regeneration and were referred to as ingrowth. Employing three independent statistical models, we investigated the number, species, and diameter of these ingrowth trees. The models were subsequently implemented into a forest simulator to project the development of Swiss forests until the mid‐21st century. The simulation results showed an ingrowth decrease and a shift in its species composition, marked by a significant reduction in Norway spruce Picea abies and concurrent increases in broadleaves. Nevertheless, the pace of this change towards climatically better adapted species composition is relatively slow and is likely to slow down even further as ingrowth declines in the future, in contrast to the fast‐changing climatic conditions. Hence, support through adaptive planting strategies should be tested in case ingrowth does not ensure the resilience of forests in the future. We conclude that since the regeneration of forests is becoming increasingly challenging, the current level at which ecosystem services are provided might not be ensured in the coming decades. [ABSTRACT FROM AUTHOR]

Due to the high reproductive investment, females are the decisive sex when making decisions about whether or not to reproduce. Generally, female scorpions display aggressive sexual behavior in response to male reproductive advances when they are not receptive. However, female receptivity can vary over time, depending on environmental factors favorable to reproduction Thus, the current study aimed to examine the correlation between the number of reproductive attempts by male Tityus pusillus scorpion and mating success over time, considering the female's behavioral response. Behavioral analyses were monthly conducted on 150 T. pusillus field-caught pairs over a five-month period. Our results indicate that despite females reacting aggressively to male advances, the persistence of the male has a positive effect in courtship probability. Furthermore, we observed variations in female behavior throughout the studied period, suggesting that female receptivity might be linked to the reproductive season. Therefore, environmental factors may play a significant role in regulating scorpion reproduction in Neotropical forests. [ABSTRACT FROM AUTHOR]

Interspecific hybridization increases genetic diversity, which is essential for coping with changing environments. Hybrid zones, occurring naturally in overlapping habitats of closely related species, can be artificially established during afforestation. The resulting interspecific hybridization may promote sustainability in artificial forests, particularly in regions facing degradation due to climate change. Currently, there is limited evidence of hybridization during regeneration of artificial forests. Here, we studied the frequency of Pinus brutia Ten. × P. halepensis Mill. hybridization in five planted forests in Israel in three stages of forest regeneration: seeds before dispersal, emerged seedlings and recruited seedlings at the end of the dry season. We found hybrids on P. brutia, but not on P. halepensis trees due to asynchronous cone production phenology. Using 94 single‐nucleotide polymorphism (SNP) markers, we found hybrids at all stages, most of which were hybrids of advanced generations. The hybrid proportions increased from 4.7 ± 2.1 to 8.2 ± 1.4 and 21.6 ± 6.4 per cent, from seeds to emerged seedlings and to recruited seedlings stages, respectively. The increased hybrid ratio implies an advantage of hybrids over P. brutia during forest regeneration. To test this hypothesis, we measured seedling growth rate and morphological traits under controlled conditions and found that the hybrid seedlings exhibited selected traits of the two parental species, which likely contributed to the fitness and survival of the hybrids during the dry season. This study highlights the potential contribution of hybrids to sustainable‐planted forests and contributes to the understanding of genetic changes that occur during the regeneration of artificial forests. [ABSTRACT FROM AUTHOR]

The first step towards understanding the conservation situation and informing conservation decision‐making is to identify the habitat loss drivers. However, for nearly all tropical biota, there is a glaring lack of information on the spatiotemporal patterns of anthropogenic drivers.Our objective was to analyse the spatial and temporal distribution of the main anthropogenic drivers of habitat loss for Bradypus torquatus and Bradypus crinitus, two endangered and endemic species to the Brazilian Atlantic Forest.We used land‐use information associated with seven major IUCN‐based threats to sloths, covering a three‐generation time window (1988–2020), to quantify the current area occupied, temporal changes, heterogeneity, and intensity of drivers across species distributions.We found that cattle farming and ranching dominate the range of both species (from 49% to 56%) and cover an area larger than the remaining native forest. Other drivers also represent important spatial and temporal features of land conversion across species distributions.Driven mainly by livestock expansion, both sloth species have experienced a significant loss of forest cover (Bradypus torquatus – 659098.70 ha; Bradypus crinitus – 139013.20 ha) in the Brazilian Atlantic forest. Overall, Bradypus torquatus showed a higher rate of deforestation than forest regeneration, whereas forest gains outweighed habitat loss for Bradypus crinitus.Our results show that a substantial area of native forest – essential for strictly arboreal species – is being continuously replaced by cattle ranching and agricultural activities, which may lead to population isolation and decline, threatening the long‐term population viability. [ABSTRACT FROM AUTHOR]

This study examines the impact of ungulate browsing on the understory dynamics of the Cansiglio Forest, the only European beech high forest in the Southern Limestone Alps. Utilizing seven pairs of fenced versus unfenced forest stands established over two decades, we assessed how fencing affects understory structure and tree regeneration. Significant differences were found in cover, height and vascular species composition in both tree regeneration and shrub layers. Fenced areas showed a significantly higher number and greater average height of young trees, supporting the hypothesis that ungulate browsing negatively impacts tree regeneration. Despite previous studies attributing the lack of silver fir (Abies alba Mill.) regeneration primarily to red deer (Cervus elaphus Linnaeus, 1758) browsing, our findings did not show a significant association of this species with fenced conditions. While Rubus abundance was higher inside fenced areas, overall vascular species richness did not differ. Our results highlight the evident effects of ungulate browsing and suggest the need to consider other factors influencing forest regeneration and understory development. Future research should establish additional study replicates, balanced across diverse site and stand structure conditions, to further explore these dynamics. [ABSTRACT FROM AUTHOR]

The amount of stored organic carbon in the forest soil depends, among other factors, on the quantity of organic litter left after the application of the silvicultural treatments during the different stages of forest growth. Considering the above, the objective of this study was to evaluate the quantity of the soil organic carbon (SOC) stored at two soil depths (0-20 cm and 20-40 cm) as a response to the application of a liberation cutting, four thinning and a seed tree regeneration method applied to different stands, effects that were contrasted against a control 60-year old stand. The results indicate that SOC ranged from 60.0 to 115.6 Mg ha-1 for the 0-20 cm soil depth and from 39.5 to 76.5 Mg ha-1 to the 20-40 cm soil depth. All the stands stored more SOC than the control, which registered an average accumulated reserve of 99.5 Mg ha-1. The liberation cutting presented the highest reservoir with 192.1 Mg ha-1. Changes in the vegetation cover caused by the cut intensities applied directly influence SOC reserves. In general, the Cambisol soils are good SOC reservoirs where the MDS was applied. [ABSTRACT FROM AUTHOR]

This study examines the recovery of late-successional forests in the Acadian Forest Region of northeastern North America after anthropogenic canopy disturbance. Tree species were sampled in a chronosequence of post-clearcut (3–54 years) and remnant late-successional forests (100–165 years) in four demographic size classes in Nova Scotia, Canada: seedlings, small saplings, large saplings, and canopy trees. Clearcut forests acquired late-successional canopy species composition within five decades after logging disturbance. Resilience to clearcutting was due principally to the persistence of residual shade-tolerant coniferous species, mostly red spruce (Picea rubens Sarg.) and eastern hemlock (Tsuga canadensis (L.) Carrière) in recovering stands. Redundancy analysis (RDA) revealed that most residual canopy species responded positively to canopy removal as small saplings, but not as seedlings. Seedlings of all residual canopy species exhibited strong associations with stand age, canopy cover, and microhabitats characteristic of older forests, such as rotting logs and smaller pieces of decayed wood. These results show that managed late-successional Acadian forests can recover quickly after clearcutting if advance tree regeneration (seedlings and saplings) is present and protected in the understory during canopy removal. Such Careful Logging methods focused on advance regeneration remain under-utilized in Acadian forests, though our results indicate they could better address silvicultural objectives such as maintaining a viable conifer component throughout stand development, as well as broader biodiversity goals in the management of late-successional forest types. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Whether environmental conditions under exotic tree plantations abandoned in the Western Ghats of India can facilitate the natural regeneration of tropical montane forest (Shola forest) tree species is being debated. In many cases, the exotic tree plantations are being cleared to allow for the restoration of native ecosystems. In this paper, we examined whether exotic tree plantations have indeed a negative effect on the regeneration of Shola forest tree species. For this, we assessed the abundance, diversity, and composition of the regeneration of Shola forest tree species in plantations, each with different dominant tree species (Acacia mearnsii , Pinus sp. and Eucalyptus sp.). We tested the abundance of regenerating native tree species against the main plantation canopy species (plantation type) as well as other environmental factors (aspect, distance to nearest Shola forest, structural diversity, slope, elevation, presence of herbivores, and canopy closure). We found that the number of native tree species regenerating in all plantation types was at an acceptable level: 1960, 1773, and 462 individuals ha−1 for Acacia , Eucalyptus , and Pinus plantations, respectively. A rare fraction analysis showed that the highest number of Shola tree species were regenerating under Acacia mearnsii (25) followed by Eucalyptus (19) and Pinus (8) plantations. The density and diversity of regenerating Shola trees was greatest under Acacia plantations and northern aspects but declined with increasing elevation. The presence of herbivores also reduced the density and diversity of Shola tree regeneration. We concluded that the restoration of Shola forest in the Western Ghats is possible in existing stands of exotic tree species and this process can be accelerated with appropriate silvicultural methods. We additionally recommend that studies involving long-term exclosures can provide valuable insights into the effects of browsing on regeneration and species composition. [ABSTRACT FROM AUTHOR]

A long-term study conducted in western Montana has demonstrated the benefits of fire hazard reduction and restoration treatments in forest ecology. The study found that mechanical treatments, combined with fire treatments, had long-lasting effects, including reduced severity of insect outbreaks and regeneration of desirable tree species. The study's simple design and clear results have made it a popular resource for outdoor education and technology transfer. The study is documented in the article "Long-term efficacy of fuel reduction and restoration treatments in Northern Rockies dry forests" by Sharon M. Hood, Justin S. Crotteau, and Cory Cleveland. [Extracted from the article]

Rhododendron ponticum (L.) is a highly invasive, non-native woody shrub that prevents tree regeneration and kills native flora. Achieving successful control of rhododendron can be difficult due to its thick waxy leaf surfaces, which discourage the absorption of foliar-applied herbicides. The spray adjuvant Mixture B NF® has therefore been used for many years to improve the efficacy, absorption, and rainfastness of foliar applications of glyphosate. We established an experiment to test if alternative non-hazardous adjuvants could be equally effective. Treatments were applied as foliar sprays and then subjected to artificial rainfall to examine rainfastness. We found that the non-hazardous adjuvants Codacide Oil® and Toil® (both based on rapeseed oil), and also SU Wett®, offered little or no benefit to the efficacy or rainfastness of glyphosate applications to rhododendron. However, further research using these adjuvants on other weed species is recommended. The only treatment in our study that showed acceptable levels of rhododendron control was glyphosate plus Mixture B NF®. Current recommendations for the control of rhododendron are therefore still valid. When foliar sprays of rhododendron bushes are required, apply 2.88–3.60 kg a.i. ha− 1 glyphosate and add Mixture B NF® adjuvant at a rate of 2 per cent of final spray volume. A minimum rain-free period of 6 h should occur after application of glyphosate products to any weed type, but if there is a risk of rainfall occurring earlier than this, and the application cannot be delayed, the use of Mixture B NF® is likely to improve rainfastness, reduce run-off and improve control. [ABSTRACT FROM AUTHOR]

Adaptive forest management gains importance as climate and disturbance regimes continue to change. Norway spruce monocultures are particularly vulnerable to those changes. Thus, there is a strong demand to convert pure spruce stands toward better adapted forest ecosystems. Silver fir has similar wood properties as Norway spruce, but is less vulnerable to droughts. Yet, little is known how to efficiently admix silver fir into Norway spruce monocultures. We analyzed seedling abundance in mature Norway spruce monocultures 1 year after soil scarification and silver fir seeding in a relatively dry region of southern Germany. Our objectives were to study the effect of soil scarification and seeding on regeneration density and to identify drivers of seedling abundance. We collected data on regeneration, forest structure, as well as soil and light conditions at 103 scarified and 25 untreated control plots. We used non-parametric independence tests to compare scarified and untreated plots. Subsequently, we used boosted regression trees to investigate the drivers of seedling abundance. Norway spruce strongly benefited from soil scarification (P  < .001), with seedling numbers even exceeding those of silver fir. Both species thrived in soils with high plant available water capacity. In contrast, seedling numbers were overall negatively affected by light. Moreover, we found a higher density of silver fir regeneration at greater distance from neighboring trees and in soils devoid of carbonate. Our study indicates that water, not light, is the limiting factor for both Norway spruce and silver fir seedlings in the study region. Seeding silver fir will likely be most effective underneath an intact canopy on deep, fine-textured soils without carbonate, while maximizing the distance to Norway spruce trees. In conclusion, silver fir seeding can be optimized to become an effective adaptive measure to diversify Norway spruce monocultures, and thus to create more resistant and resilient forest ecosystems. [ABSTRACT FROM AUTHOR]

The pressure to plant seedlings in unprepared instead of prepared soil in forest regeneration is increasing, although seedlings' growth in unprepared soil is poorer. One way to improve seedlings' growth could be to add arginine phosphate to the planting hole at the time of planting. In field studies, abiotic and biotic damage normally disturbs studies which seek to determine growth effects, especially in unprepared soil. The study's aims were (i) to clarify whether it was possible to investigate the differences between varying soil layer structures mimicking site preparation methods and seedling treatments in simulated planting places in partly controlled conditions; and (ii) to investigate the effects of arginine phosphate (arGrow® Granulat) on the growth, especially root growth, of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) container seedlings in those simulated planting places. Seedlings of both tree species were planted in 40 l pots sunk partly into the soil in a sandy field. Before planting, pots were filled with soil layers mimicking layers in soil without any site preparation treatment and in spot mounds. After one growing season, the differences in growth parameters between treatments were small in Norway spruce seedlings, and no significant benefits of arginine phosphate were observed. The soil in the spruce pots was fine-textured and contained a thick organic layer. More studies in more common forest soil types suitable for Norway spruce seedlings are needed to be sure about the growth responses. In Scots pine seedlings, adding arginine phosphate granules to the planting holes improved the growth of seedlings at least in the first summer after planting in soil layers mimicking no mechanical site preparation situation, and the growth improvement may even have compensated the mounding effects. In conclusion, mimicking site preparation methods in large pots was a promising method by which the differences between site preparations methods as well as effects of seedling treatments, in our case arginine phosphate, on the growth of conifer seedlings, can be tested. [ABSTRACT FROM AUTHOR]

Forests play a key role in the mitigation of global warming and provide many other vital ecosystem goods and services. However, as forest continues to vanish at an alarming rate from the surface of the planet, the world desperately needs knowledge on what contributes to forest preservation and restoration. Migration, a hallmark of globalization, is widely recognized as a main driver of forest recovery and poverty alleviation. Here, we show that remittance from migrants reinforces forest recovery that would otherwise be unlikely with mere migration, realizing the additionality of payments for ecosystem services for China's largest reforestation policy, the Conversion of Cropland to Forest Program (CCFP). Guided by the framework that integrates telecoupling and coupled natural and human systems, we investigate forest-livelihood dynamics under the CCFP through the lens of rural out-migration and remittance using both satellite remote sensing imagery and household survey data in two representative sites of rural China. Results show that payments from the CCFP significantly increases the probability of sending remittance by out-migrants to their origin households. We observe substantial forest regeneration and greening surrounding households receiving remittance but forest decline and browning in proximity to households with migrants but not receiving remittance, as measured by forest coverage and the Enhanced Vegetation Index derived from space-borne remotely sensed data. The primary mechanism is that remittance reduces the reliance of households on natural capital from forests, particularly fuelwood, allowing forests near the households to recover. The shares of the estimated ecological and economic additionality induced by remittance are 2.0% (1.4%∼3.8%) and 9.7% (5.0%∼15.2%), respectively, to the baseline of the reforested areas enrolled in CCFP and the payments received by the participating households. Remittance-facilitated forest regeneration amounts to 12.7% (6.0%∼18.0%) of the total new forest gained during the 2003–2013 in China. Our results demonstrate that remittance constitutes a telecoupling mechanism between rural areas and cities over long distances, influencing the local social-ecological gains that the forest policy intended to stimulate. Thus, supporting remittance-sending migrants in cities can be an effective global warming mitigation strategy. [ABSTRACT FROM AUTHOR]

The frequency of severe wildfires is on the rise in the Mediterranean Basin as a result of climate change and land abandonment. Recurrent wildfires may retard or impede ecosystem recovery, frequently requiring the implementation of restoration practices. In that context, a post‐fire deer exclusion experiment was conducted in a Mediterranean mixed forest ecosystem with high population densities of deer species (Fallow deer and Red deer). A deer exclusion area was established as a form of restoration intervention to promote post‐fire vegetation recovery. We surveyed plant species during the second and third springs after fire in both deer‐excluded and deer‐allowed areas in order to detect changes in the community. We analyzed the plant species composition, species diversity, and structure of herbaceous and woody plant communities. We also compared the frequency of annual and perennial herb species, functional groups, and post‐fire plant regeneration strategies. The main differences were due to differences between springs rather than of deer‐excluded and deer‐allowed plots. Deer consumed both woody and herbaceous species, favoring the assemblage of herbaceous over woody species. Deer favored the establishment of annual forbs, including unpalatable and/or exotic species, while limiting the abundance of graminoids. Observed deer impacts could have been magnified during the second spring by a drought. Our study demonstrates that deer exclusion can be an effective restoration practice for promoting post‐fire herbaceous regeneration in forests with significant densities of wild ungulates, although seasonal effects may override restoration practice effects. [ABSTRACT FROM AUTHOR]

A novel Bayesian spatial distributional regression model is presented to predict forest structural diversity in terms of the distributions of the stem diameter at breast height (DBH) in the protection forests in Ebensee, Austria. The distributional regression approach overcomes the limitations and uncertainties of traditional regression modeling, in which the conditional mean of the response is regressed against explanatory variables. The distributional regression addresses the complete conditional response distribution, instead. In total 36,338 sample trees were measured via a handheld mobile personal laser scanning system (PLS) on 273 sample plots each having a 20 m radius. Recent airborne laser scanning (ALS) data were used to derive regression covariates from the normalized digital vegetation height model (DVHM) and the digital terrain model (DTM). Candidate models were constructed that differed in their linear predictors of the two gamma distribution parameters. In the distributional regression approach, covariates can enter the model in a flexible form, such as via nonlinear smooth curves, cyclic smooths, or spatial effects. Supported by Bayesian diagnostics DIC and WAIC, nonlinear smoothing splines outperformed linear parametric slope coefficients, and the best implementation of spatial structured effects was achieved by a Gaussian process smooth. Model fitting and posterior parameter inference was achieved by using full Bayesian methodology and MCMC sampling algorithms implemented in the R-package BAMLSS. With BAMLSS, spatial interval predictions of the DBH distribution at any new geo-locations were enabled via straightforward access to the posterior predictive distributions of the model terms and by offering simple plug-in solutions for new covariate values. A cross-validation analysis validated the robustness of the proposed method's parameter estimation and out-of-sample prediction. Spatial predictions of stem count proportions per DBH classes revealed that regeneration of smaller trees was lacking in certain areas of the protection forest landscape. Therefore, the intensity of final felling needs to be increased to reduce shading from the dense, overmature shelter trees and to promote sunlight for the young regeneration trees. [ABSTRACT FROM AUTHOR]

Tropical forests are being reduced by human activities. The use of fire for agricultural expansion generates areas dominated by the bracken fern Pteridium, where forest regeneration is slow. This may be caused by seed limitation, especially of animal‐dispersed seeds, due to the absence of seed dispersers from the forest in deforested areas, calling for restoration strategies to assist forest regeneration. We installed bird perches and artificial bat roosts to evaluate their effect on the density, species richness, and composition of animal‐dispersed seeds and seedlings of tree and non‐tree species in bracken‐dominated areas in the tropical montane forest of Bolivia. We found that perches and bat roosts increased the density and species richness of animal‐dispersed seeds and established seedlings. The seeds and seedlings dispersed by birds were clumped under the perches, while the seeds and seedlings dispersed by bats were distributed around the roosts. Perches had a higher density and species richness of seeds and seedlings compared to bat roosts, suggesting that the use of perches could be a better option as a restoration tool in bracken‐dominated areas. The increase in seed rain and seedling establishment of animal‐dispersed species in perches and bat roosts supports seed limitation, hindering forest succession in bracken‐dominated areas. The use of bird perches accompanying other restoration techniques is a promising restoration strategy to accelerate forest regeneration in tropical areas dominated by Pteridium, which are widely distributed. [ABSTRACT FROM AUTHOR]

Background: Tree seedling regeneration in forests is often hindered by the competitive influence of dense understory bamboo competition. While localized studies have investigated the ecological effects of understory bamboo removal on tree seedlings, a comprehensive analysis at a global scale is lacking. In this meta-analysis, we synthesized 497 observations from 32 experimental studies to assess the overall effects of understory bamboo removal on tree seedling regeneration. Results: The results showed that understory bamboo removal enhanced tree seedling survival, emergence, and height growth. However, the response of tree seedlings to bamboo removal varied depending on regeneration characteristics, forest types, and bamboo removal methods. Specifically, understory bamboo removal increased the survival rate of deciduous seedlings but had no significant effect on evergreen seedlings. For regeneration stages, bamboo removal had a significant positive effect on the survival rate of saplings but not on seedlings. Regarding differences across forest types, bamboo removal significantly increased the emergence density of seedlings in deciduous broadleaf forests but had a significant negative influence in evergreen and mixed evergreen-deciduous forests. Additionally, natural removal of bamboo showed a greater positive effect on seedlings than bamboo removal by artificial or animal gnawing methods. Furthermore, we found that the duration of bamboo removal, mean annual temperature, precipitation of seasonality, and soil pH strongly influenced the response ratios of tree seedling regeneration. Conclusions: Our meta-analysis demonstrates the significant effects of understory bamboo removal on multiple facets of tree seedling dynamics across different regeneration characteristics, forest types, and bamboo removal methods. In addition, our study emphasizes that the duration of bamboo removal, climate, and soil pH have a critical effect on tree seedling regeneration. Our findings elucidate the effects of understory bamboo removal on seedling regeneration, offering robust scientific insights for sustainable forest management. [ABSTRACT FROM AUTHOR]

Canopy gaps are a prevalent disturbance form in forest ecosystems that promote forest regeneration and succession by modifying the heterogeneity of the microenvironment. However, a significant knowledge gap exists in comprehending the global-scale impact of canopy gaps on soil nutrient properties, which is related to forest management and conservation tactics. In this study, 518 paired observations derived from 31 peer-reviewed articles were meta-analyzed to evaluate the overall response of soil nutrient properties to canopy gaps. The results showed that canopy gaps increased NO3−–N (+ 22.20%) and MBP (+ 194.17%). The canopy gap decreased the content of TN, MBC, and C:P ratio by 9.27%, 19.58%, and 19.25%, respectively. The size of canopy gaps significantly reduced SOC (−14.37%), MBC (−27.45%), TN (−11.98%), NH4+–N (−65.26%), C:N (−15.77%, −16.02%) and C:P ratio (−28.92%), but significantly increases NO3−–N (+ 37.25%). Hence, it is advisable to establish a critical gap size that caters to the specific soil fertility requirements of various regions for the optimal release of soil nutrients. These findings hold substantial significance for optimizing canopy gap management, comprehensively understanding the impact of canopy gaps on soil nutrient properties, and facilitating decision-making to assess soil fertility following canopy gap disturbances. [ABSTRACT FROM AUTHOR]

Physiological water stress induced by low root temperatures might contribute to species‐specific climatic limits of tree distribution. We investigated the low temperature sensitivity of root water uptake and transport in seedlings of 16 European tree species which reach their natural upper elevation distribution limits at different distances to the alpine treeline. We used 2H‐H2O pulse‐labelling to quantify the water uptake and transport velocity from roots to leaves in seedlings exposed to constant 15°C, 7°C or 2°C root temperature, but identical aboveground temperatures between 20°C and 25°C. In all species, low root temperatures reduced the water transport rate, accompanied by reduced stem water potentials and stomatal conductance. At 7°C root temperature, the relative water uptake rates among species correlated positively with the species‐specific upper elevation limits, indicating an increasingly higher sensitivity to lower root zone temperatures, the lower a species' natural elevational distribution limit. Conversely, 2°C root temperature severely inhibited water uptake in all species, irrespective of the species' thermal elevational limits. We conclude that low temperature‐induced hydraulic constraints contribute to the cold distribution limits of temperate tree species and are a potential physiological cause behind the low temperature limits of plant growth in general. Summary statement: Our experiment reveals a relationship between the cold sensitivity of root water uptake and the elevational distribution limits of temperate tree species. We propose restricted water supply at low, nonfreezing soil temperatures as a fundamental mechanism behind the cold growth limitation of trees. [ABSTRACT FROM AUTHOR]

Human activities cause changes in the structure of landscapes that may impact negatively on wildlife at different levels. Agriculture and livestock, for example, have frequently led to landscapes of forest fragments and isolated trees within grass/crops matrices. These changes influence the distribution and behavior of animals, and the key ecological processes that depend on them. In this study, we analyzed how tree isolation influences the patterns of acorn dispersal by scatter-hoarding rodents in Holm oak Quercus ilex fragmented woodlands of Central Spain. Our results show that an increase in the degree of tree isolation promotes the concentration of rodents under oak canopies looking for cover and food during the seeding season. This concentration increases dramatically the levels of competition among rodents for space and acorns beneath oak canopies, which resulted in an increase in acorn caching to reduce seed pilferage by conspecifics, thus favoring acorn dispersal from the mother tree. These shifts in rodent spatial distribution and behavior would favor tree recruitment through increased rates of seed dispersal, which may counterbalance to some extent the potential negative effects of forest fragmentation given the overall loss of seed-producing trees. Significance: There is little information on how forest fragmentation and the consequent tree isolation affect animal behavior. This implies that the behavior of such animals could provide behavioral feedbacks to the forest in response to fragmentation, either intensifying or mitigating the impacts of fragmentation on natural forest regeneration. This study reveals how seed-dispersing rodents change seed predation and dispersal patterns in response to the degree of tree isolation. An increase in tree isolation favors the seed dispersal process by scatter-hoarding rodents, promoting mutualistic interactions between rodents and trees in fragmented forests. Thus, the negative impacts of forest fragmentation on forest regeneration may be compensated by the improved seed dispersal of scatter-hoarding rodents. These findings emphasize the critical need to address habitat fragmentation from a behavioral perspective and highlight how small-scale interactions can have significant impacts on ecosystem dynamics and conservation. [ABSTRACT FROM AUTHOR]

In the Western Himalayas, the turnover of litterfall for the economically important tree species Picea smithiana (spruce) is very high (9708.17 ± 1341.07 kg/ha/y), and the decomposition rates (decay constant – k) are also very low ranging from 0.221 to 0.294. Accordingly, 10–13 years is required to decompose 95% of the total litter in these forests. This high turnover of litter, coupled with slow decomposition rates, is the main hindrance in the natural establishment of this coniferous species. The regeneration of these forests is not keeping pace with the removal of tree species, and this problem has resulted in the depletion of growing stock over a large area. Keeping in view the economic importance of this tree species and the poor regeneration caused by the accumulation of litter, this study aimed to isolate Trichoderma, owing to its fast-growing nature, from the rhizosphere of P.smithiana to evaluate its degradation potential to manage the leaf litter by composting to convert it to a more usable product called compost which can be supplemented to the same ecosystem to ameliorate the soil quality and growth of the trees. The Trichoderma was qualitatively screened for its enzymatic activity based on forming a hydrolytic zone. The results revealed that out of six enzymes screened, it was found to be positive for four enzymes: Amylase (29 ± 2.08 mm), lipase (25 ± 1.52 mm), laccase (85 ± 2.64 mm), and cellulase (39 ± 2.08 mm). Due to the ability of Trichoderma to produce cellulase and laccase enzymes, it can be inferred that it can degrade the main components of litter, that is, cellulose and lignin. [ABSTRACT FROM AUTHOR]

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a main method of forest regeneration, stump sprouting plays a crucial role in forest community succession and vegetation restoration. We aimed to investigate the response of stump sprouting capacity to stubble height, unveil its nutrient-accumulation and allocation strategies and determine the appropriate stubble height most favorable for stump sprouting of Hippophae rhamnoides ssp. sinensis. Fifteen-year plants with signs of premature aging were coppiced at 0, 10 and 20 cm from the ground level. With the increase in stubble height, the number of stump sprouts increased linearly, and the survival rate decreased linearly. The height, diameter and cluster width of stump sprouts first increased, reached the highest level at a stubble height of 10 cm and then decreased. The contents and reserves of N, P, K, Ca and Mg showed a similar trend as the growth, positively correlating with each other. Compared with the control (no coppicing), the coppicing increased the nutrient element allocation of leaves, vertical roots and horizontal roots. Magnesium plays an important role in stump sprouting. The findings suggest that coppicing changed the accumulation ability and allocation pattern of nutrient elements, and further affected the sprouting ability of stumps. The best stubble height for stump sprouting and nutrient accumulation potential was 11.0–14.0 cm estimated by the regression. [ABSTRACT FROM AUTHOR]

The natural regeneration of forest ecosystems is crucial for their sustainability, but uncertainties have impeded the regeneration of some tree species. Identifying influencing factors and effective strategies to enhance seedling survival and growth is essential. We investigated factors affecting the natural regeneration of Larix principis‐rupprechtii and provided insights into seedling survival and growth. Eighteen artificial L. principis‐rupprechtii forest plots were established and monitored for 3 years. A logistic regression analysis and generalized linear models were used to investigate the influence of stand age, diameter at ground level, height, and other microhabitat factors on seedling regeneration. The microhabitat factors significantly influenced the overall L. principis‐rupprechtii regeneration density, as well as the density and growth of regenerated trees in different height classes. The area under the curve values for total nitrogen (0.796), total phosphorus (0.726), soil moisture (0.759), and litter thickness (0.633) were the highest, indicating a significant impact on the survival rate and mortality of the seedlings. Among these values, total nitrogen sensitivity (0.857) and specificity (0.810) were the highest, and the optimal threshold was 0.940. The survival rate decreased with increasing forest age, and the stands aged 4–7 years with a height of 1–2.5 m and a diameter at the ground level of approximately 2 cm constituted a relatively vulnerable and critical set of conditions for the survival of L. principis‐rupprechtii seedlings. The model showed that at 12 years old, L. principis‐rupprechtii trees were no longer vulnerable to mortality. The Kaplan–Meier model predicted future seedling survival through the construction of the comprehensive influence value and the measured seedling survival number. The model can be used to evaluate the survival rate for the final regeneration of a species, and targeted artificial seeding or replanting can improve the proportion of seedlings that survive. Our findings contribute to elucidating the factors affecting the natural regeneration of forest species and provide valuable insights for the development of effective regeneration strategies. [ABSTRACT FROM AUTHOR]

Wildfires are among the most serious disturbances that affect forest biodiversity, damaging both flora and fauna. In some burned areas, vegetation recovery is a long and complex process that requires the support of restorative actions. This study evaluated changes in forest structural features after a fire that affect habitat suitability for Rhinocryptids, an endemic group of bird species that are indicators of biodiversity in the temperate forests of South America. The study area was the Malleco National Reserve, Chile, where the main ecosystems are temperate forests. Four species from the Rhinocryptidae family of birds were used as bioindicator species. This group of species is endemic to temperate forests in South America. After fires occurred in 2002 and 2015, affecting temperate forests dominated by several Nothofagus species, two field inventories were carried out in 2016 and 2018. These inventories recorded the presence of Rhinocryptids and some forests structural features. Differences between the two stages of forest regeneration were assessed using statistical tests (T-test and Wilcoxon–Mann–Whitney test) and a classification model was proposed to determine the presence of Rhinocryptidae species. The statistical analysis of forest structural features showed that the variables more relevant in the habitat recuperation are vertical stratification (p-value < 0.001) and understory cover (p-value = 0.053). The trained decision tree to predict the presence of Rhinocryptidae species had an accuracy of 65.22%. This model showed that the coexistence of more than one Rhinocryptidae species occurs when vertical stratification is not mono-stratified and the density is lower than 335 trees ha−1. Our results can help forest managers to consider forest structure as a suitable habitat for certain major wildlife species when implementing post-fire recovery plans. [ABSTRACT FROM AUTHOR]

Forest diversity is the outcome of multiple species-specific processes and tolerances, from regeneration, growth, competition and mortality of trees. Predicting diversity thus requires a comprehensive understanding of those processes. Regeneration processes have traditionally been overlooked, due to high stochasticity and assumptions that recruitment is not limiting for forests. Thus, we investigated the importance of seed production and seedling survival on forest diversity in the Pacific Northwest (PNW) using a forest gap model (ForClim). Equations for regeneration processes were fit to empirical data and added into the model, followed by simulations where regeneration processes and parameter values varied. Adding regeneration processes into ForClim improved the simulation of species composition, compared to Forest Inventory Analysis data. We also found that seed production was not as important as seedling survival, and the time it took for seedlings to grow into saplings was a critical recruitment parameter for accurately capturing tree species diversity in PNW forest stands. However, our simulations considered historical climate only. Due to the sensitivity of seed production and seedling survival to weather, future climate change may alter seed production or seedling survival and future climate change simulations should include these regeneration processes to predict future forest dynamics in the PNW. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'. [ABSTRACT FROM AUTHOR]

El Niño-induced drought, which is intensified by climate change, can have huge impacts on soil microbial biomass and plant productivity in tropical forests. We tested whether drought-induced turnover of soil microbial biomass can be a potential source of phosphorus (P), the limiting nutrient, for the reproduction of tropical forest trees (mast fruiting). We measured the seasonal variations in soil microbial biomass P and soil solution P concentrations including the periods before and after drought in a dipterocarp forest in Indonesia. Drought resulted in a decrease in soil microbial biomass C, N, and P, followed by a recovery after re-wetting. There was a sharp peak of soil solution P concentrations during the drought. The significant difference between soil microbial biomass P before and after drought amounted to 2.0 kg P ha−1. The potential P release from microbial turnover is not negligible compared to the additional P demand for fruit production (1.0 kg P ha−1) as well as the annual demand for litter production (2.5 kg P ha−1 year−1). In addition to the accumulation of nutrients for several non-fruiting years and their re-distribution in tree biomass, drought-induced microbial turnover can be nutrient subsidies for dipterocarp reproduction in highly-weathered soils. [ABSTRACT FROM AUTHOR]

This study assessed whether a natural regeneration or active tree‐planting reforestation strategy better restored the C and N‐cycle processes and associated microbiota within soils after 18 years in a Premontane Wet Life zone site in Monteverde, Costa Rica, compared to adjacent old secondary forest and pasture soils (both >60 years). Our findings apply to small‐scale restoration sites (<0.5 ha plots) commonly used in Monteverde. Both restoration strategies showed recovering soil C and N‐cycle processes with similar levels of TN, NH4+, NO3−, Biomass‐C, and efficiency of organic C use. Both strategies appeared to positively influence the recovery of the levels and community compositional stability of the Actinobacterial, Acidobacterial, N‐fixing (N‐Fixer) bacterial, ammonium‐oxidizing bacterial, and complex organic C‐degrading fungal communities. The main differences between the two strategies were that the tree‐planted and pasture soils had similar compositions of the Actinobacterial, N‐Fixer, and Fungal complex organic C degrader, while the natural regeneration and pasture soils had similar compositions of these groups and the Acidobacteria. However, the community compositions of all five microbial groups were different between restored forest and the old secondary forest soils. These results suggest that while the soil ecosystems from both reforestation strategies are recovering, after 18 years, there is still more recovery to occur. Lastly, possible indicators of post‐restoration soil ecosystem enhancement included increasing constancy of critical microbial group composition, efficiency of organic C conversion to biomass, Biomass‐C, NH4+, NO3−, and levels of Acidothermus, Acidobacteria subgroups 2, 3, and 5, Archaeorhizomyces, Anaeromyxobacter, Bradyrhizobium, Nitrosomonas, Flavobacterium, and Nitrospira. [ABSTRACT FROM AUTHOR]

Under increasing human‐related threats to forests, many studies suggest that increasing tree species diversity may boost forest resilience by enhancing the range of species' responses to disturbances. However, it remains unclear whether passive or active forest management strategies should be applied to increase tree diversity. This issue would benefit from investigating which management and environmental factors, together with species' functional traits, influence temporal changes in tree species diversity.We explored the influence of the bioclimatic region, land‐use history, forest cover, protection, management, forest structure and changes in temperature and precipitation, to explain tree species diversity changes in NE Iberian forests, by comparing 3141 plots from the Spanish National Forest Inventory sampled between 1989 and 2016. Moreover, we assessed which species' functional traits (dispersal habit, drought and shade tolerance) were most relevant for diversity changes.After 27 years, tree species richness and diversity moderately increased in the tree and regeneration layers. This trend occurred mostly in long‐established, non‐recently managed forests and in those with a lower initial basal area. Increasing temperature had negative effects for diversity increase in the tree layer but positive for the regeneration compartment, while decreasing precipitation showed the opposite effects.Tree species with higher drought tolerance, and especially those animal‐dispersed ones arriving from the regional pool, mostly contributed to the local diversity increase. This pattern occurred in all forest types, although the taxonomic array of species varied.Synthesis and applications. The main drivers influencing the passive increase in tree species diversity suggest a primary role of diminishing forest exploitation in this recovery process, fine‐tuned by climatic changes. This ecological scenario has particularly favoured animal‐dispersed tree species with higher drought tolerance, which mostly led the diversity increase. A higher presence of such highly mobile and drought‐tolerant species can be crucial to increase functional diversity and, ultimately, increase forest resilience under future scenarios of greater aridity. In light of these results, management strategies should continue fostering the restoration of diversity in once intensively exploited forests while ensuring the maintenance of the already gained tree species diversity. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The causative agent of sooty bark disease, Cryptostroma corticale, has, for some years, caused increased damage to maples (Acer spp.) in Germany and throughout Europe. It has been stated that this pathogen can occur latently in Acer. In this study, the composition of endophytic fungi of woody stem tissues of sycamore (Acer pseudoplatanus) saplings were analysed in order to investigate whether C. corticale is present in young, visually healthy maple trees from natural regeneration. The most abundant taxa of the 30 isolated endophytes were Diaporthe cf. rudis and Petrakia irregularis. An association of five fungal species (Biscogniauxia mediterranea, Coniochaeta velutina, Gibellulopsis catenata, Neocucurbitaria quercina, Tangerinosporium thalitricola) with A. pseudoplatanus was reported for the first time. Cryptostroma corticale was not present in the juvenile sycamore stems. Furthermore, its pathogenicity was studied in comparison to other pathogens associated with A. pseudoplatanus, namely Diplodia mutila, Dothiorella sp., Nectria cinnabarina, Neonectria coccinea, Neonectria punicea and Stegonsporium pyriforme. The longest necroses were induced by C. corticale followed by N. coccinea. In a trial with a C. corticale spore suspension sprayed directly on stem bark, the fungus could be re-isolated from woody tissue, however necroses were evoked only when the bark was wounded prior to infection. The results from the experiments presented here function as additional evidence for the ability of C. corticale to establish endophytically within the host and, in particular, for the ability of the fungus to establish a successful infection/entrance through intact bark. [ABSTRACT FROM AUTHOR]