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Large terrestrial herbivorous mammals (LTH‐mammals) influence plant community structure by affecting seedling establishment in mature tropical forests. Many of these LTH‐mammals frequent secondary forests, but their effects on seedling establishment in them are understudied, hindering our understanding of how LTH‐mammals influence forest regeneration in human‐modified landscapes.We tested the hypothesis that the strength of LTH‐mammals' effects on seedling establishment depends on landscape protection, forest successional stage and plant species' traits using a manipulative field experiment in six 1‐ha sites with varying successional age and landscape protection. In each site, we established 40 seedling plot‐pairs, with one plot excluding LTH‐mammals and one not, and monitored seedlings of 116 woody species for 26 months.We found significant effects of LTH‐mammal exclusion on seedling survival contingent upon the protection of forests at the landscape level and forest stage. After 26 months, survival differences between LTH‐mammal exclusion and non‐exclusion treatments were greater in protected than unprotected landscapes. Additionally, plant species' traits were related to the LTH‐mammals' differential effects, as LTH‐mammals reduced the survival of seedlings of larger‐seeded species the most. Overall, LTH‐mammals' effects translated into significant shifts in community composition as seedling communities inside and outside the exclosures diverged. Moreover, lower density and higher species diversity were found as early as 12 and 18 months outside than inside exclosures.Synthesis and applications. Insight into the interactions between LTH‐mammals and seedling communities in forest regeneration can be instrumental in planning effective restoration efforts. We highlight the importance of landscape protection in seedling survival and the role of LTH‐mammals in promoting seedling diversity in mature forests but also in secondary successional forests. The findings suggest that conservation efforts and possibly trophic rewilding can be important approaches for preserving diversity and influencing the trajectory of secondary tropical forest succession. However, we also caution that an overabundance of LTH‐mammals may adversely impact the pace of forest succession due to their preference for large‐seeded species. Therefore, a comprehensive wildlife management plan is indispensable. Additionally, longer term studies on LTH‐mammals are necessary to understand the effects of temporal fluctuations that are undetected in short‐term studies. [ABSTRACT FROM AUTHOR]

As one of the main components of forest operations and sustainable management, forest roads affect the vegetation communities around the road. In this study, the effects of the edge of forest roads were investigated to understand the changes caused by the network of forest roads on the Hyrcanian forest ecosystem in northern Iran. In order to investigate the impact of forest roads on the biodiversity of herbaceous species, tree regeneration and lichen, sampling was used at different distances from the road in two controlled and harvested areas. The effects of roads on vegetation diversity in relation to soil characteristics were also investigated. The results showed that harvesting caused the destruction and reduction of tree, herbaceous and lichen regeneration, but the physical and chemical properties of the soil were not affected. The distance from the road has affected the diversity and richness of herbaceous and lichen, tree regeneration and all physical and chemical characteristics of the soil (except C). There was a significant correlation between most of the physical and chemical properties of the soil with the regeneration of trees and herbaceous species. Also, most of the physical and chemical properties of soil have increased with increasing distance from the road. Results showed that the buffering effect of the roadside in these forests up to a distance of 45 m had an effect on diversity and richness. Also, the results of this study are consistent with the fact that the road affects the biodiversity and properties of the forest soil. [ABSTRACT FROM AUTHOR]

To avoid the surrounding pollination, seed orchards of Finnish plus trees have been established in Ukraine, i.e., far from their natural distribution. However, it is unknown whether the pollination site affects the frost hardiness (FH) of the progenies and thus their use in forest regeneration in Finland. Using whole-plant freezing tests, we examined the FH of plus tree seed orchard progenies in Finland and Ukraine, with three lots of seeds from each orchard, twice during cold acclimation in controlled conditions. The FH of needles, as assessed immediately after the freezing tests, was higher in the Finnish than Ukrainian seed orchard progenies. The variation in the FH of needles was high among the progenies, ranging from − 44 to − 79 °C by relative electrolyte leakage (REL), and from − 29 to − 46 °C by chlorophyll fluorescence (CF). However, when FH was assessed based on the growth of shoots and roots in the greenhouse after three weeks, the differences between the progenies and orchards disappeared. The FH was then between − 10 and − 15 °C based on shoot growth, between − 6 and − 12 °C based on root growth, and between − 8 and − 16 °C based on the number of new root tips. The results imply an epigenetic effect on FH of needles but no effect of progeny or orchard on FH of roots. In summary, it seems to be possible to use seed produced in southern Ukraine in practical reforestation actions in southern Finland. [ABSTRACT FROM AUTHOR]

Planted monocultures of even-aged coniferous tree species are abundant worldwide but increasingly damaged by biotic and abiotic stressors and disturbances. In Central Europe, a fundamental goal of ecologically oriented forest management is thus the conversion of pure and often even-aged coniferous stands into structurally more diverse and mixed broad-leaved forests. This conversion is often achieved by single-tree selection resulting in small canopy openings that promote artificial or natural regeneration. Consequently, forest conversion aims at altering stand structure and tree communities. In order to describe the status quo of forest conversion and derive implications for forest management, we investigated changes of tree composition and forest structure in the Bavarian Spessart mountains in southwest Germany. We conducted a resurvey of 108 semi-permanent plots in four different coniferous stand types of Norway spruce, Scots pine, Douglas fir, and European larch about 30 years after the initial survey. We found significant differences in the stratification and cover of respective forest layers between the two sampling periods that indicated an increase in stand structural heterogeneity. While species richness of the overstorey remained constant, species richness and diversity of the shrub and lower canopy layer increased significantly. Regenerating "winner" species included late-successional broad-leaved (e.g., European beech, sessile oak), pioneer broad-leaved (e.g., silver birch, rowan) and shade-tolerant coniferous (e.g., silver fir, Douglas fir) species. Although Norway spruce was significantly reduced in the overstorey, it regenerated in parts extensively in the understorey. We conclude that the forest conversion in the Spessart mountains was overall successful in terms of diversifying forest structure and tree species. Its effects are, though, still emerging and the stands are in a transitional phase. Besides the preferred natural regeneration of target tree species, forest management may consider active measures to guide the facilitated diverse tree community of previously pure and even-aged coniferous stands towards stand maturity. [ABSTRACT FROM AUTHOR]

Many nations administer national forest inventory programs for unbiased estimation of forest attributes over broad spatial and temporal extents. However, management and conservation decisions often demand reliable estimates for finer spatiotemporal domains. In the western US, wildfire activity is expanding and postfire regeneration must contend with a warmer, drier climate. We evaluate the potential of K nearest neighbor (KNN) strategies for estimation of stocking across postfire measurements of Forest Inventory & Analysis plots in 11 western US states, and subsequently for model-assisted (MA) estimation of stocking over domains defined by aggregations of burned areas within individual states and 4-year periods. In particular, we develop and evaluate a form of constrained KNN that allows for unbiased MA domain estimation under simple random sampling by drawing only on measurements external to a domain of interest. KNN strategies based on geographically, radiometrically, and climatically proximate measurements are found to provide more accurate estimates of stocking at the plot level than domain means. Applying the selected external KNN strategy also reduced standard errors of MA domain estimates by 16% over direct domain estimators, but bias correction introduces substantial variability over synthetic estimates. Further applications of the external constraint imposed on KNN are discussed. [ABSTRACT FROM AUTHOR]

The paper discusses the current mosaic, syntaxonomic diversity, and elements of their composition in the recent dynamics of the forests of Valdai National Park. Using the remote methods of tree cover monitoring, a complex assessment was performed of a degree of its inherited and anthropogenic fragmentation; proportions of areas occupied by various forest communities; and the intensity of woody regeneration on meadows since 1990 (the year when the national park was established). Based on high-resolution Sentinel-2B (2017) satellite images (10–60 m), a map tile of the Valdai forest administrative unit (Lesnichestvo) was created, specifying their current state, natural and anthropogenic mosaic, and trends in succession. Assessment of the diversity of forest communities included identification of the main syntaxa of the floristic classification of the park vegetation and forests per se and refinement of their relation to the dominant classification units and forestry typology. The paper presents a brief retrospective analysis of agrarian development in the region and its implication for a structure and dynamics of forests in the park. The conclusion was made about the development of the conservation-driven successions (forestation of meadows due to woody regeneration) in recent decades and intensification of forest degradation due to the recreational use in the shore areas of Velye, Valdaiskoye, Uzhin, and other lakes. Importantly, the park's historic Old Russian forest-field-meadow landscape that has been forming for centuries on the Valdai Hills characterised by the high biological and landscape diversity is currently deteriorating. Identification of patterns of the natural and anthropogenic landscape mosaic will allow for more rational regulation of the authorized commercial operations, including recreational activities, on lands within the park boundaries and will prevent a decline in the original biodiversity. [ABSTRACT FROM AUTHOR]

The present study is an attempt to analyze the pattern of trees distribution, population structure and regeneration status along altitudinal gradients by sampling vegetation within each 100 m altitudinal belts from 2100 m a.s.l. upto treeline ecotone (3300 m a.s.l.) in Kedarnath Wildlife Sanctuary in western Himalaya. The study documented 39 species of trees belonging to 32 genera and 21 families; among these 13 (61.90%) families and 27 (84.38%) genera were monotypic indicating poor genetic base and recent speciation of the species in the region. The results of vegetation assessment reveal that tree density, species diversity (H´) and species richness decreased with increasing altitude. The average total tree basal area (TBA) was found 60–70 m2/ha upto 2800 m altitude, which considerably declined (24 m2/ha) upto 2800 m onward upto treeline ecotone. The forest population structure showed a classic inverse J-shape curve pattern in the lower altitude zone, suggesting a healthy proportional conversion rate of individuals (seedlings > saplings > adults) of tree species into higher size classes. The absence of tree saplings in many forest stands, suggests that seedlings had failed to reach sapling stage in recent years. At higher altitudes, the population structure was hill shaped, indicates poor regeneration of tree species. These findings have significant implications for appropriate forest management and conservation planning in the Himalayan region. [ABSTRACT FROM AUTHOR]

Bryophytes, which include mosses, liverworts and hornworts, indeed play a significant role in the natural dynamics of native forests. They contribute to fundamental ecological processes such as tree regeneration. In this context, the objective was to analyse the association of bryophytes with Nothofagus seedlings, as well as whether the substrates where bryophytes grew influenced bryophyte‐tree seedling association, in sub‐Antarctic forests at two contrasting landscapes (coastal and mountain) of Tierra del Fuego (Argentina), to better understand their impacts on the natural regeneration processes. We hypothesized that bryophytes act as a substrate for seed germination and initial regeneration growth in pure and mixed forests of N. pumilio and N. betuloides, resulting in widespread tree seedlings–bryophyte associations in all landscapes. In each forest and landscape location, 60 transects were established (10 m in length) to evaluate bryophyte cover (by point intercept method) and substrate type (bare soil, decaying wood and litter cover) where they were growing. An adaptation of the relative interaction index (RII) based on tree seedling cover associated with bryophyte species (%) and tree seedling cover in the absence of bryophytes (%) was calculated and analysed to assess competition or facilitation between bryophytes and tree seedlings. Nothofagus pumilio seedlings were less abundant in bryophytes compared to other substrates, suggesting an inhibitory effect on the germination and/or survival of N. pumilio. In contrast, the seedlings of N. betuloides, in both pure and mixed forests, exhibited higher abundance on bryophyte substrates, particularly in mosses at mountain landscape (RII = 0.83 ± 0.08 in litter and 0.62 ± 0.11 in decaying wood). These findings suggest that bryophytes play a facilitating role for N. betuloides seedlings during germination and initial phases of growth, mainly in the mountain. Therefore, their conservation promotes N. betuloides forest continuity, both in pure and mixed structures. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry 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.)

Context: Mediterranean landscapes are undergoing severe transformations (land-use change and homogenization) that threatens biodiversity and the services these ecosystems provide. These effects can differ amongst biodiversity facets (plants vs. birds, taxonomic vs. functional) and ecosystem functions (e.g., seed dispersal, forest regeneration, pest control), although these are still poorly understood in Mediterranean landscapes. Objectives: Our study aims at understanding how Mediterranean landscape characteristics and land use (tree croplands, shrublands and pine, oak and mixed forest) affect the diversity of birds and plants, and how these changes in biodiversity could affect ecosystem functioning. Methods: In 2020–2021, we sampled 49 (5 × 5 m) plots in South-eastern Spain and from five different land uses: tree croplands, shrublands, and pine, oak and mixed forests. We measured land use, habitat diversity and size, together with birds and plant diversity. We assessed both direct and indirect (via bird and plant diversity) effects of landscape characteristics on 6 different ecosystem functions related to forest regeneration, predation, herbivory or aboveground biomass, which imply interactions between birds, plants and their environment. Results: Plant communities responded mainly to local features (land use), whereas birds did so to habitat size and landscape diversity (within 500 m radius). Seed and caterpillar predation were more affected by bird's diversity, whereas regeneration capacity of woody species was driven by both plants and birds. Land use was amongst the most important drivers of all measured functions, with generally higher functioning levels in oak and mixed forests than in the rest of land uses. Conclusions: Our results emphasize the complementary information obtained when considering multiple biodiversity facets in studying the consequences of landscape transformation. We also show that these multiple biodiversity changes can be as important as those of land-use or landscape characteristics for ecosystem functioning. [ABSTRACT FROM AUTHOR]

Context: Afforestation has been widely implemented to deliver climate change mitigation and restore ecosystem benefits. However, the efficacy of afforestation has been deputed. The regeneration ability of most plantations in Northern China has been suggested to fail to reach their optimal. Objectives: Here, we compared the regeneration ability of plantations and natural forests in Northern China and explored how the climate factors and site features can determine the regeneration ability. We hypothesize that the deficient regeneration ability of plantations is mainly due to the single tree age and high stand density. Furthermore, the effects of climate factors cannot be ignored. Methods: We investigated the climate factor, stand features, tree radial growth, and regeneration ability (the number of cones and seedlings) of two dominant conifers, Larix principis-rupprechtii and Pinus sylvestris var. mongolica in natural forests and plantations in northern China. Results: Our analysis shows a significant difference in the number of both cones and regenerated seedlings produced by plantations and natural forests within the same site (P < 0.05). The stand density of plantations had a significant negative effect on the generation of seedlings (P < 0.05). Additionally, climatic factors, such as mean annual temperature and mean precipitation play a major role in regulating the heat and water availability for forest regeneration. Finally, we found that the inter-annual fluctuations in the radial growth of trees are also related to the number of seedlings produced, which is likely due to higher growth fluctuations indicating poorer drought adaptation of trees. Conclusions: Our study suggests that no single factor can explain the regeneration failure of plantations in semi-humid and semiarid regions of China. Both site features and climatic factors affect the production of seedlings. Future afforestation should follow low-density afforestation in areas with favorable climatic conditions for tree growth. [ABSTRACT FROM AUTHOR]

Context: Tropical forests in mainland Southeast (MSEA) have important conservation values and provide critical ecosystem functioning and services. With climate change and increasing anthropogenic activities, these forests can be lost to other land use types or degraded. Objectives: We aim to understand how these forests have changed under the context of MSEA's rapidly changing physical and socioeconomic environments in recent decades. Methods: We employed satellite-derived tree cover products, primarily the MODIS-based Vegetation continuous field (VCF) data, to investigate changes in forest cover with a focus on potential forest degradation to savannah since 2000 for the four MSEA countries, i.e., Thailand, Laos, Cambodia, and Vietnam. Results: We found an overall increasing trend of savannah (defined as places with tree cover between 10 and 55%) during the period 2000–2020. However, the sources of the increased savannah area differed significantly between 2000–2009 and 2009–2020: In the earlier decade, the positive trend of the savannah area was primarily attributed to tree regeneration from grasslands; while during the more recent decade, the degradation (savannization) of forests was the major cause. Fire disturbance primarily controlled interannual variation in tree cover for the savannah gain during the period of 2000–2009, while high atmospheric water demand drove the degradation of forests during the period of 2010–2020. Conclusions: Our analysis sheds light on the understanding of changing forest landscapes in a globally important region of tropical forests, which is critical for informing land management and tropical forest protection. [ABSTRACT FROM AUTHOR]

Agrotechnological procedures related to forest management, including planting, are burdensome and the energy expenditure of the people working is very high. Nowadays, planting is usually carried out manually, and sometimes with the use of planters coupled to universal tractors. Occasionally, planters mounted on high-power carriers are used, and usually the seedlings are removed from their cassettes and placed manually into the planter's storage unit. In connection with the above, the prototype of a mobile automatic device for performing forest regeneration tasks and afforestation of post-agricultural and reclaimed areas (RoboFoR) was designed. The main task of this vehicle is planting forest tree seedlings with a covered root system, which are collected directly from their nursery cassettes. This study presents the structure, principle of operation and results of operational tests of the seedling storage and feeding unit. It was found that the unit achieved the expected work efficiency. However, imperfections in the system related to the non-centralized distribution of seedlings in containers and the high variability of biometric characteristics of the seedlings were also identified. A new solution for this unit was proposed, which will increase the reliability of collecting the seedlings. A new solution requires greater computational power of the control unit as well as equipping the sensor system with a technologically advanced root neck detection system. The new concept also assumes the possibility of independent movement of each gripper. [ABSTRACT FROM AUTHOR]

The article aims to describe the patterns of changes in the number of vascular plant species in communities at different stages of forest regeneration after clearcutting using the space-for-time substitution method. Large-scale logging in boreal forests leads to a simplification of the territory's forest cover (the formation of even-aged stands), which in turn leads to a decrease in the diversity of forest communities and species diversity. These tendencies have been confirmed for many groups of organisms, especially those associated with old trees and dead wood; however, this is not so clear for vascular plants. We investigated plant communities at different stages of regeneration. We used the so-called space-for-time substitution (chronosequence) method of building dynamic series for four forest ecotopes, where industrial clearcuts are most actively carried out. We showed that the fertility of forest ecotopes determines the species pool—the richer the conditions, the more species that can potentially inhabit the community. At the same time, the structure of the tree stand significantly affects the composition and number of species in the community. The lowest species richness was in old-growth forests characterized by the dominance of one species in the tree stand and one or two vascular plant species in the ground cover. With insignificant fluctuations in the average number of species between stages of forest regeneration after logging, some communities at clearcuts in bilberry (Vaccinium myrtillus L.) pine (Pinus sylvestris L.) and spruce (Picea abies (L.) H.Karst.) forests have high species diversity due to the occupation of the site by species of open habitats. These clearcuts are located not far from settlements and close to roads. [ABSTRACT FROM AUTHOR]

The natural regeneration of the temperate oak forests is often insufficient. Acorns of the oak serve as the basis of the recruitment and key food resources in these ecosystems, thus the crop size, the germination success and seed predators have crucial roles in the process. Wild boar (Sus scrofa) is often considered as one of the main mitigating agents in oak regeneration. Therefore, in our study we analyzed and compared the spatial patterns of the acorn density and the patches rooted by wild boar within and among the different examined time intervals in a 28 ha Turkey-sessile oak (Quercus cerris, Q. petraea) forest stand. Data were collected between 2016 October and 2019 December. In the acorn density patterns, intra-annual similarities were recognized mainly, regardless of the crop size. Meanwhile, rooting patterns showed inter- and intra-annual similarities in mast years and intra-annual overlaps in non-mast years, indicating that masting is a fundamental driver of wild boar foraging behavior. However, a direct local connection between the rooting intensity and the acorn density could not be shown, as wild boars never fully depleted the acorns, even in intensively used patches. This study can help in predicting the intensively rooted forest patches, providing opportunities to manage wildlife conflicts. [ABSTRACT FROM AUTHOR]

This study presents the long-term forest history in the forest–tundra ecotone of the Low Yenisei River basin. The new high-resolution pollen and macroscopic charcoal data were inferred from the 8.6 m long peat archive covering the last 6300 years. Climate reconstructions are based on the application of the best modern analogue technique using pollen data. Our findings suggest an alternation of phases of middle-taiga forests of Larix sibirica, Abies sibirica, Picea obovata, and Pinus sibirica (intervals of climate warming: 6320–6050, 5790–5370, 4480–4220, and 3600–2700 cal yr BP, respectively) and open larch woodlands with the participation of Betula, Picea, and Pinus sibirica, typical for northern taiga (intervals of climate cooling and increasing humidification: 5370–4480, 4220–3600 cal yr BP, respectively). The vegetation pattern of the region became similar to the modern one around 2700 cal yr BP. Climate warming caused a northward shift of vegetation-zone boundaries in Yenisei Siberia and an expansion of the range of Abies sibirica by about 200 km to the north compared to the present day. The increased frequency of fires and biomass burning during warm periods may promote the melting of the local permafrost, thereby enhancing the tree growth and regeneration. [ABSTRACT FROM AUTHOR]

Implementing adaptation and mitigation strategies in forest management constitutes a primary tool for climate change mitigation. To the best of our knowledge, very little research so far has examined light detection and ranging (LiDAR) technology as a decision tool for operational cut-tree marking. This study focused on investigating the potential of airborne LiDAR data in enhancing operational tree marking in a dense, multi-layered forest over complex terrain for actively supporting long-term sustainable forest management. A detailed tree registry and density maps were produced and evaluated for their accuracy using field data. The derived information was subsequently employed to estimate additional tree parameters (e.g., biomass and tree-sequestrated carbon). An integrated methodology was finally proposed using the developed products for supporting the time- and effort-efficient operational cut-tree marking. The results showcased the low detection ability (R2 = 0.15–0.20) of the trees with low DBH (i.e., regeneration and understory trees), while the dominant trees were accurately detected (R2 = 0.61). The stem biomass was accurately estimated, presenting an R2 of 0.67. Overall, despite some products' low accuracy, their full and efficient exploitability within the aforementioned proposed methodology has been endeavored with the aim of actively contributing to long-term sustainable forest management. [ABSTRACT FROM AUTHOR]

The goal of this study is to detect indicators of damage to birch stands in western Siberia by spongy moth (Lymantria dispar L.) using remote sensing methods. The need for such indicators is due to the fact that the size of the study area is about 1 million square kilometers, and ground methods are too laborintensive. It is crucial for these indicators to differentiate the effects of insects from other destructive factors like fires and droughts. During the 2021–2022 fieldwork, we identified 18 areas for trial (intensive damage due to caterpillars) and control. For each area, we obtained seasonal time-series data of vegetation index NDVI mean values within its boundaries. We acquired the data from a Sentinel-2 satellite with a spatial resolution of 10 m. Relative reduction indices of NDVI during the season were introduced for pairs of damaged–control plots. We also considered the effect of foliage regeneration on damaged trees. The obtained indicators demonstrate increased analytical significance in identifying areas affected by pests compared to the simple reduction in vegetative indices. [ABSTRACT FROM AUTHOR]

In regenerated oak forests, weeds are present throughout the year, with the ones appearing in early spring representing a major problem. Hence, the aim of this study was to examine herbicides for early spring broadleaved weed control in regenerated oak forests while the seedlings are in a dormant stage. During 2019 and 2020, two experiments were set up in regenerated pedunculate oak forests with 2- and 3-year-old seedlings, and two herbicides were applied in two doses: fluroxypyr at doses of 360 g a.i. ha−1 and 540 g a.i. ha−1 and clopyralid at doses of 100 g a.i. ha−1 and 120 g a.i. ha−1. Fluroxypyr and clopyralid significantly reduced early spring broadleaved weeds in the regenerated pedunculate oak forests, but both doses of fluroxypyr provided greater control of the presented weeds than the applied doses of clopyralid. Manual weeding reduced broadleaved weeds in the experiments, but that method did not have a long-term effect on the reduction in weeds. The applied doses of the herbicides fluroxypyr and clopyralid did not cause phytotoxicity symptoms in the dormant oak seedlings. All investigated treatments significantly reduced fresh broadleaved weed biomass compared to the control. Fluroxypyr and clopyralid can be successfully used for the control of many early spring broadleaved weeds in regenerated pedunculate oak forests, but 2- and 3-year-old oak seedlings must be in the dormant stage. [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.)

Successful regeneration of commercial species is central to the long-term sustainability of forests managed for wood production. We studied two species of tree seedlings planted after group selection and single-tree selection harvesting in a 20 ha replicated silviculture experiment in stands dominated by coast redwood (Sequoia sempervirens (D.Don) Endl.). Treatments consisted of complete harvest in 1 ha group selection opening (GS), low-density dispersed retention (LD), aggregated high-density retention (HA), and dispersed high-density retention (HD). One year after planting, seedlings planted on a southwest aspect had the lowest survival rate, while northeast aspects had nearly complete survival rates. As expected, redwood had a higher survival rate than coast Douglas-fir (Pseudotsuga menziesii var menziesii (Mirb.) Franco). Survival rates exhibited a rise-peak-fall pattern with stand density, most notably on southwest-facing slopes, ranking LD > HA ≈ HD > GS treatments. Deer browsing of planted seedlings was a pervasive problem where Douglas-fir were preferentially browsed over redwood. In treatments with higher retention densities, browsing was less likely, ranking GS > LD > HA > HD treatments. Further from watercourses at higher elevation, the probability of browsing diminished. Overall, dispersed treatments outperformed aggregated and GS treatments by simultaneously maximizing survival and minimizing browsing of planted seedlings. We did not perform site preparation or herbicide treatment of re-sprouting hardwoods following harvest, and therefore recommend testing the effectiveness of understory vegetation management to enhance seedling survival. Consideration could also be given to planting more seedlings in anticipation of lower survival rates, and/or implementing seedling protection measures when and where heavy browsing is expected. [ABSTRACT FROM AUTHOR]

With the recent return of large carnivores to forest ecosystems, an important issue for forest owners and managers is how large predators influence the behaviour of their natural prey and, consequently, cervid browsing pressure on forest regeneration. To investigate this issue, we analysed deer pressure on Scots pine and European beech plantations in northern Poland's ecosystems with and without permanent wolf populations. Two characteristics were used to describe deer browsing patterns in plantations: distance from the forest edge (spatial pattern of browsing) and number of saplings browsed (browsing intensity). Beech saplings were more intensively browsed by deer compared to pine saplings. In a forest ecosystem not inhabited by wolves, spatial variation in browsing patterns on small-sized beech plantations was the same between the edge and the center. In contrast, browsing pressure by deer was greater at the edges on large-sized pine plantations. The presence of wolves reduced deer browsing on beech and increased browsing on pine saplings. In addition, deer foraging behaviour changed in large-sized pine plantations, and browsing pressure increased only in the central areas of the plantations. We assume that the presence of wolves in a forest landscape is an important factor that alters browsing pressure on the youngest stands and their spatial pattern, and that this may be a major factor in stand regeneration, especially in small forest patches. [ABSTRACT FROM AUTHOR]

Natural selection for plant species in heterogeneous environments creates genetic variation for traits such as cold tolerance. While physiological or molecular analyses have been used to evaluate stress tolerance adaptations, combining these approaches may provide deeper insight. Acacia koa (koa) occurs from sea level to 2300 m in Hawaiʻi, USA. At high elevations, natural koa populations have declined due to deforestation, and freeze tolerance is a limiting factor for tree regeneration. We used physiology and molecular analyses to evaluate cold tolerance of koa populations from low (300–750 m), middle (750–1500 m), and high elevations (1500–2100 m). Half of the seedlings were cold acclimated by exposure to progressively lowered air temperatures for eight weeks (from 25.6/22.2°C to 8/4°C, day/night). Using the whole plant physiology‐freezing test and koa C‐repeat Binding Factor CBF genes, our results indicated that koa can be cold‐acclimated when exposed to low, non‐freezing temperatures. Seedlings from high elevations had consistently higher expression of Koa CBF genes associated with cold tolerance, helping to explain variation in cold‐hardy phenotypes. Evaluation of the genetic background of 22 koa families across the elevations with low coverage RNA sequencing indicated that high elevation koa had relatively low values of heterozygosity, suggesting that adaptation is more likely to arise in the middle and low elevation sources. This physiology and molecular data for cold tolerance of koa across the elevation gradient of the Hawaiian Islands provides insights into natural selection processes and may help to support guidelines for conservation and seed transfer in forest restoration efforts. [ABSTRACT FROM AUTHOR]

Information about post-disturbance regeneration success and successional dynamics is critical to predict forest ecosystem resistance and resilience to disturbances and climate change. Our objective was to identify and classify post-disturbance empirical research conducted by the Canadian Forest Service (CFS) of Natural Resources Canada and their collaborators to provide guidance on future research needs, improving our understanding of post-disturbance recovery in a Canadian context. To achieve our objective, we collected and classified peer-reviewed and non-published literature produced by the CFS between 1998 and 2020 that concerned post-disturbance ecology. We focused on research addressing natural or anthropogenic disturbances, such as wildfires, pest outbreaks, windthrows, forest management, seismic lines, and those that studied processes related to soil, vegetation, fauna, hydrology, and microbial communities. We found that forest harvesting was the disturbance most studied by CFS between 1998 and 2020, followed by fire. Despite the fact that large, forested areas are affected annually by pests, studies on recovery after pest outbreaks were scarce. Other disturbances, such as mining and seismic lines or other abiotic disturbances were rare in CFS literature. Most studies (70%) examined changes in vegetation related to forest management and fire and they were mainly focussed on post-disturbance tree regeneration success. Post-disturbance changes in understory species diversity were also well-studied. Our results provide a geographic overview of CFS research on post-disturbance recovery in Canada and enable the identification of key knowledge gaps. Notably, research focusing on recovery after natural disturbances was underrepresented in the assessed literature compared to studies centered around harvesting. Long-term research sites, chronosequences that substitute space for time, and studies focused on consecutive disturbances are especially important to maintain and establish sustainable forest management strategies in the face of climate change. [ABSTRACT FROM AUTHOR]

Silvicultural regeneration methods focus on manipulating the forest canopy, but success can depend on the use of site preparation to control competing vegetation, including the density of advance regeneration, and create suitable microsite conditions for germination and seedling establishment. Tip-up mounds are known to provide favorable conditions for some tree species, but the creation of tip-up mounds as a method of site preparation has scarcely been investigated. We assessed effects of artificial tip-up mounds on tree seedling composition across a gradient of regeneration methods and residual overstory densities 2–4 years post-implementation. We found that tree seedling communities on mounds in some treatments were compositionally distinct from untreated reference plots. However, no tree species exhibited a strong affinity for mounds when analyzed independently from the regeneration method, and much of the difference in composition was associated with lower dominance of maples (Acer spp. L.) on mounds. As maples are strong competitors in forests regenerated with selection systems, reduced maple competition on artificial mounds could advantage desired under-represented species and aid in natural regeneration over time. Therefore, in stands where promoting tree species diversity is desirable, implementing artificial tip-up mounds as part of a long-term strategy may be beneficial. [ABSTRACT FROM AUTHOR]

Alberta's forests are becoming increasingly disturbed and fragmented by the cumulative effects of anthropogenic disturbances exacerbated by the enduring footprint of seismic lines on the landscape. Forest harvesting and subsequent reforestation activities (e.g., site preparation and tree planting) may facilitate tree growth on seismic lines when forestry companies incorporate them into management areas. In this study, forest regeneration was assessed along transects on and off seismic lines within four cutblocks in northwestern Alberta. Tree, sapling, and shrub characteristics were measured, and tree cookies from a subset of trees on and off seismic lines were used to model height growth. No difference in total tree, sapling, or shrub counts on and off seismic lines was found although trees on seismic lines were growing at slightly slower rates compared to the adjacent cutblock, and Alnus viridis was more abundant on seismic lines. Our results suggest that, despite some species-level differences and modest differences in tree growth rates, trees on seismic lines within cutblocks are regenerating similarly to other trees growing in the post-harvest stand. These findings indicate that forest harvesting, and subsequent reforestation, could represent an important tool in conducting landscape-level restoration in mixedwood forests where seismic lines have not naturally recovered. [ABSTRACT FROM AUTHOR]

Context: Native early-successional plants and invasive exotic plants often colonize the same disturbed space and have similar functions, making interactions likely. Knowing whether these interactions are facilitative or competitive across different scales will help determine the influence of such species across a forested landscape. Objective: We evaluated the impacts of an early-successional, nitrogen-fixing native (facilitator), Robinia pseudoacacia, and an allelopathic invasive (inhibitor), Ailanthus altissima, on regeneration, basal area, and diversity of forests at local and regional scales. Methods: Locally, all woody stems were mapped in three post-disturbance, mid-successional plots at two sites in Virginia, US. Plots contained A. altissima or R. pseudoacacia or both. Target species were evaluated regionally and spatially using USDA Forest Inventory and Analysis data across 31 eastern states, US. Results: Spatial contagion was found between A. altissima and R. pseudoacacia at both scales. Regeneration of A. altissima was much greater than that of R. pseudoacacia but native tree regeneration was negatively associated with both target species. Regionally, R. pseudoacacia was more common than A. altissima. At both scales, A. altissima was more likely to form dense stands than R. pseudoacacia. Locally, plot types did not differ in tree diversity. Regionally, R. pseudoacacia plots had higher tree diversity than plots without either target species. Conclusions: Robinia pseudoacacia and A. altissima's positive association is maintained into mid- and late-successional forests and A. altissima inhibits regeneration locally and regionally. Robinia pseudoacacia shows a positive effect on diversity but only when compared with mature forests at the regional scale. [ABSTRACT FROM AUTHOR]

High temperatures threaten tree survival and regeneration. A few pine species, such as Pinus oocarpa and Pinus canariensis, resprout after complete defoliation, a likely consequence of evolving in volcanic environments. Pinus pinea and Pinus pinaster rely on other mechanisms to survive wildfires. We hypothesized that the needle water potential (Ψ) and needle osmotic potential (Ψs) would decrease more under hot wind in resprouting species, a strategy of needle sacrifice in accordance with the hydraulic segmentation hypothesis. We submitted two-year-old seedlings to a two-phase hot wind treatment, consisting of one hour at 39 °C followed by five minutes at 70 °C. Phase 2 killed all needles. In non-resprouting species, Ψ decreased steeply at the beginning of Phase 1 and remained between −2 MPa and −4 MPa afterward, maintaining the loss of stem hydraulic conductance below the 50% threshold. On average, resprouting species had 15% lower wood densities and kept 51% higher stem water contents than non-resprouting species after Phase 2. The loss of hydraulic conductance did not affect resprouting. The increase in hydraulic conductance toward the base of the stem was lowest in P. canariensis, suggesting a lower degree of conduit tapering in the only species that had not undergone heteroblastic change. We measured the lowest Ψ and highest Ψs in the most xeric P. canariensis and the opposite in the most mesic P. oocarpa, highlighting the roles of xylary and extra-xylary hydraulic resistances in compartmentalizing the needle to preserve the stem. The measurement of both Ψ and Ψs allowed us to characterize the strategies of response to hot wind in resprouting and non-resprouting pine species. [ABSTRACT FROM AUTHOR]

In northern Alberta, Canada, much of treed boreal peatlands are fragmented by seismic lines—linear disturbances where trees and shrubs are cleared for the exploration of fossil fuel reserves. Seismic lines have been shown to have slow tree regeneration, likely due to the loss of microtopography during the creation of seismic lines. Inverted soil mounding is one of the treatments commonly applied in Alberta to restore seismic lines and mitigate the use of these corridors by wildlife and humans. We assessed the effects of mounding on understory plants and arthropod assemblages three years after treatment application. We sampled five mounded and five untreated seismic lines and their adjacent treed fens (reference fens). Compared to reference fens, mounded seismic lines showed on average lower bryophyte (6.5% vs. 98.1%) and total understory cover (47.2% vs. 149.8%), ground-dwelling spider abundance (226.0 vs. 383 individuals), richness (87.2 vs. 106.4 species) and diversity (19.0 vs. 24.6 species), rove beetle abundance (35.2 vs. 84.8 individuals), and ant richness (9.0 vs. 12.9 species). In contrast, rove beetle and ground beetle richness (39.0 and 14.5 species, respectively) and diversity (16.8 and 7.8 species, respectively) were higher on mounded seismic lines compared to reference fens (richness: 18.0 and 7.5 species, respectively; diversity: 7.0 and 3.8 species, respectively). This is one of the first studies to assess arthropod responses to restoration efforts in the context of oil and gas disturbances in North America, and our results highlight the need to incorporate multiple taxa when examining the impact of such treatments. [ABSTRACT FROM AUTHOR]

Temperate conifer forests stressed by climate change could be lost through tree regeneration decline in the interior of high-severity fires, resulting in type conversion to non-forest vegetation from seed-dispersal limitation, competition, drought stress, and reburns. However, is fire triggering this global change syndrome at a high rate? To find out, I analyzed a worst-case scenario. I calculated fire rotations (FRs, expected period to burn once across an area) across ~56 million ha of forests (~80% of total forest area) in 11 western USA states from 2000 to 2020 for total high-severity fire area, interior area (>90 m inward), and reburned area. Unexpectedly, there was no trend in area burned at high severity from 2000 to 2020 across the four forest types studied. The vulnerable interior area averaged only 21.9% of total high-severity fire area, as 78.1% of burned area was within 90 m of live seed sources where successful tree regeneration is likely. FRs averaged 453 years overall, 2089 years in interiors, and 19,514 years in reburns. Creation of vulnerable interior area in a particular location is thus, on average, a 2000+ year event, like a very rare natural disaster, and reburns that may favor type conversion to non-forest have almost no effect. This means that, from 2021 to 2050 at most, only 3.0–4.2% of total forest area may become a vulnerable interior area, based on a likely high aridity-based climate projection of future fire and a higher scenario, where rates in the exceptional 2020 fire year have become the norm. These findings show that increased management to reduce high-severity fires is not currently needed, as the risk to forests from this global change syndrome is likely quite low up to 2050. Faster and larger disturbances (e.g., severe droughts) are more likely to cause most tree mortality or forest loss that occurs by 2050. [ABSTRACT FROM AUTHOR]

Background: Individual pioneer tree species often dominate early tropical dry forest succession and thereby affect possible successional pathways. Mimosa acantholoba var. eurycarpa is a highly dominant species in the tropical dry forest in Mexico. Hypothesis: Mimosa acantholoba var. eurycarpa exerts an inhibitory effect on the germination, establishment, survival, and early growth of light-demanding pioneers, while facilitating these processes for shade-tolerant old-growth forests species. Studied species: Lonchocarpus torresiorum, Lysiloma divaricatum, Mimosa acantholoba var. eurycarpa and Vachellia farnesiana. Study site and dates: Nizanda, Oaxaca, Mexico, 2020-2021. Methods: In 12 early successional plots, we applied three levels of crown cover removal (100, 50, and 0 %) of established trees of the dominant pioneer legume (M. acantholoba var. eurycarpa). We sowed seeds of the four study species in each experimental plot and recorded their germination, establishment, survival, and early growth over a 2-mo period. Results: The removal of crown cover of established M. acantholoba var. eurycarpa trees did not significantly affect germination. Lysiloma divaricatum had the highest germination probability, the fastest germination, and the highest establishment probability regardless of treatment. Lonchocarpus torresiorum had the highest establishment probability in plots where the crown cover of established M. acantholoba var. eurycarpa trees was removed The survival probability of both shade-tolerant species was highest in the 100 % removal treatment. Conclusions: Despite successful germination of shade-tolerant species, their survival is inhibited under the dense canopy of the dominant legume. Therefore, interventions to reduce the crown cover area of this dominant legume may stimulate forest recovery.

Forests in the United States continue to lose biodiversity and many fail to regenerate due to high deer (family Cervidae) abundance. Declines in biodiversity and overall ecosystem health due to high deer populations increases prevalence of wildlife and human diseases associated with increasing tick abundances and decreases forest resilience and the ability to deliver benefits provided by healthy ecosystems. In the eastern and midwestern United States, white-tailed deer (Odocoileus virginianus) are the main stressor, while in the western U.S. elk (Cervus elaphus) and black-tailed and mule deer (Odocoileus hemionus) can become equally problematic. Federal and State Wildlife Agencies are responsible for environmental stewardship and management of deer, migratory and endangered species, yet they lack authority to address human health concerns or commercial interests (we acknowledge tribal authority to manage wildlife as an important contributor to conservation). Furthermore, State Wildlife Agencies have retained their traditional focus to manage wildlife for recreational hunters while neglecting their obligations to manage wildlife in the interest of all citizens rather than special interest groups. Fragmented institutional arrangements and widely scattered responsibilities for human health, environmental conservation and management, agriculture, and commerce among tribal, federal, and state agencies have allowed deer impacts to grow into nationwide conservation and human health crises. Given that local, regional, and state-level initiatives have failed to provide appropriate remedies, federal leadership is now essential to integrate concerns among disciplines, policy domains, regions, habitats, and biota. We recommend developing a National Strategy to build strong collaborative efforts and diverse and inclusive relationships across environmental, human health and economic interests. These should reach beyond state boundaries to comprehensively address interrelated deer, human health, forest, and conservation crises. A well-coordinated and collaborative approach has the potential to overcome traditional turf battles between tribal, state, and federal interests by recognizing joint responsibilities and obligations to manage wildlife as a public trust resource. This collective approach can protect species before they become endangered, avoiding further declines in environmental and human health.

Extended Abstract Introduction and Objective: Obtaining information and identifying the changes and dynamics of forest ecosystems in different developmental stages is necessary for optimal management, restoration and improvement of forests. The aim of This research was to investigate the effect of different development stages of the stand on tree regeneration and understory species in the mixed hornbeam stand in spring and summer (due to the beginning of vegetative activities until the optimal vegetative stage of herbaceous plants) in the forestry plan of Gorgan Shasat-Kalate district two was done. Material and Methods: In order to investigate development stages, after forest surveying, three rectangular half-hectare sample plots with dimensions of 50 x 100 meter for each development stage based on the characteristics provided by Leibundgut and Korpel in the field of the structure pattern of development stages and phases in natural forests were used. In order to study and investigate the vegetation cover, five small sample plots (20x20 meters), one of them in the center and four other in the four corners. In each sample plot, the percentage of herbaceous species cover and the tree regeneration frequency were recorded. To investigate and compare diversity in different development stages, use the diversity indices of Simpson and Shannon-Wiener, and to calculate the richness, use the richness indices of Margalf and Manhinik, and for evenness, use the evenness indices of Smith-Wilson and Evenness in PAST and R software (package Adiv software and specieseve function( were used. Results: The results showed that the number of plant species in the degradation stage is more than the initial and optimal stages. Diversity indices of understory species and tree regeneration species showed that the diversity of Shannon and Simpson in the two seasons of spring and summer in the optimal stage was lower than the initial and degradation stages. Also, Smith-Wilson and Evenness indices had the highest values in both spring and summer in the optimal stage. The highest value of the Menhinic richness index of understory species was determined in the optimal stage in the spring season, while no significant difference was observed between the different stages in the summer season. The highest value of Margalef richness index of tree species regeneration in both seasons was also observed in the degradation stage. Conclusion: Based on the results of the present research, it can be stated that different development stages have an effect on the diversity of herbaceous species and forest regeneration. Therefore, there are significant implications of sustainable management on the vegetation layer, which should be considered in future of forest management strategies.

Preserving the integrity of forests after logging and fires involves the development of various methods to promote natural reforestation. One of these methods is the creation of environmentally friendly and safe biofertilizers based on waste from the timber industry. The use of innovative biofertilizer in the Pogorelsky Bor (pine forest) of the Krasnoyarsk forest-steppe had a positive effect on the biopotential of soils and the amount of Scotch pine (Pinus sylvestris L.) undergrowth after selective felling. In the first two years, in all experimental variants, an increase in the activity of hydrolytic and redox enzymes of the soil by 1.5–2 times was noted; they increased compared to the control. Immediately after the introduction of biofertilizer in the soil microbial complex, the amount of cellulolytics increases to 62 thousand CFU/g of soil in the logging areas. By the end of the growing season, both in the first and in the second year of application of biofertilizer in the experimental variant of the logging, sprouts of Scots pine were recorded 2–3 times more than in the control variant of this site. The fire that took place in May 2022 led to an increase in the total number of microorganisms up to 38 million CFU/g of soil and an increase in the activity of a number of hydrolytic enzymes during the growing season in experimental plots using biofertilizer. At the end of the growing season in 2022, there was no response of microorganisms to the application of biofertilizer, and actinomycetes dominated in the soil microbial complex. Also, by September of this year, the cellulose-decomposing potential, humification, and the activity of hydrolytic and redox enzymes decreased by more than 2 times. Biofertilizer significantly stimulated the formation of shoots and undergrowth of pine in the post-fire areas of the technological areas of felling (logging sites and portage) by 2 times.

Tree fecundity and recruitment have not yet been quantified at scales needed to anticipate biogeographic shifts in response to climate change. By separating their responses, this study shows coherence across species and communities, offering the strongest support to date that migration is in progress with regional limitations on rates. The southeastern continent emerges as a fecundity hotspot, but it is situated south of population centers where high seed production could contribute to poleward population spread. By contrast, seedling success is highest in the West and North, serving to partially offset limited seed production near poleward frontiers. The evidence of fecundity and recruitment control on tree migration can inform conservation planning for the expected long-term disequilibrium between climate and forest distribution.

Forests are under intense human pressure, hindering their restoration. A potential solution to regeneration problems is the adoption of tree shelters, which have demonstrated protective benefits in the early establishment of forest plantations. A 9-year study was conducted in the Maamora forest (Morocco) to evaluate the effects of tube shelters and regeneration methods (direct seeding and seedling) on the growth and survival of cork oak (Quercus suber) plantations. A split-plot design was developed with three replicates of 36 plants for each of the four shelter treatments, including T0 (control), T1 (Tubex 1.20 m), T2 (Tubex 1.50 m), and T3 (Tubex 1.80 m) for a total of 964 plants, where periodic inventories were conducted to assess plant survival and growth. Our results show regeneration methods and shelters significantly influenced the survival of cork oak. Direct-seeded plants were more successful than those from seedlings, presenting survival rates of up to 97%. Despite a minimal shelter effect at the beginning, their positive influence was strong later on. Only plants installed with the 1.20 m shelter had an overall success rate of over 50%. Regeneration method had a strong influence on height and diameter growth, with seedling units showing taller plants initially, which shifted to direct-seeded plants in subsequent years. Conversely, the effect of shelters on growth parameters was generally non-significant. Nonetheless, sheltered trees exhibited greater height and diameter than unsheltered trees, particularly in the latter years. Sheltered plants showed an overall faster rate of vertical growth, while unsheltered plants showed faster radial growth.

In some cases, it is difficult to promote climax tree species in the forest stand composition. In the Czech Republic, silver fir (Abies alba Mill.) is a typical example. This study offers an evaluation of the use of two improving compounds for tree plantations in the initial stage of growth in Central Bohemia. In the experiment, we measured the initial growth performance of a young fir plantation treated with a brassinolide compound (concentration 1 : 100 and 1 : 200) and Bio-Algeen® prior to planting and compared it with control treatment: we assessed height, root collar diameter, vitality and mortality rate during the period 2014-2019. Cumulative mortality rate of the plantation reached 25% at the end of the monitoring period, without any significant differences between variants. Height increment of the variant treated with Bio-Algeen® was significantly (P < 0.05) lower than the growth of brassinolide-treated variants, all treated variants were comparable with the control variant. The plantation underwent a drought-stress period in 2014 and 2015, which resulted in worsened vitality and colour across variants. As a result of the simple economic analysis, the most expensive inputs are planting stock and labour, therefore the price and application of additional substances should not affect decision-making.

Selective logging in the tropics results in carbon emissions but also creates favourable environmental conditions for the regeneration of tree species and carbon recovery. We evaluate tree regeneration and recovery of biomass in selectively logged forests impacted by timber harvesting on the Yucatán Peninsula, Mexico. Fieldwork was conducted in two annual cutting areas logged in 2001 and 2009. Plots were established in felling, skidding and log landing sites. Regeneration of functional tree groups characterized by their growth, light demand, timber use, and recovery rates of biomass and carbon were assessed. Regeneration of 68 tree species in 54 genera and 27 families were found. Of these, 50% corresponded to marketable timber species. There was a greater presence of light-demanding seedlings and species in both annual cutting areas. Carbon recovery five and thirteen years after logging was 50.6 Mg ha−1 and 62.7 Mg ha−1, respectively, reflecting an annual gain of 1.51 Mg ha−1. Felling sites presented the highest diversity and carbon recovery and contained the highest quantity of trees >5 cm DBH and proportion of shade-tolerant species, providing a variety of future crop trees. Low logging intensity and practices that reduce impacts can result in the successful recovery of timber species and forest carbon.

Habitat conversion and climate change are fundamental drivers of biodiversity loss worldwide but are often analyzed in isolation. We used a continental-scale, decades-long database of more than 150,000 bird nesting attempts to explore how extreme heat affects avian reproduction in forests, grasslands, and agricultural and developed areas across the US. We found that in forests, extreme heat increased nest success, but birds nesting in agricultural settings were much less likely to successfully fledge young when temperatures reached anomalously high levels. Species that build exposed cup nests and species of higher conservation concern were particularly vulnerable to maximum temperature anomalies in agricultural settings. Finally, future projections suggested that ongoing climate change may exacerbate the negative effects of habitat conversion on avian nesting success, thereby compromising conservation efforts in human-dominated landscapes. [ABSTRACT FROM AUTHOR]

Forests are one of the most important natural resources for humans, and understanding the regeneration probability of undergrowth in forests is very important for future forest spatial structure and forest management. In addition, the regeneration of understory saplings is a key process in the restoration of forest ecosystems. By studying the probability of sapling regeneration in forests, we can understand the impact of different stand factors and environmental factors on sapling regeneration. This could help provide a scientific basis for the restoration and protection of forest ecosystems. The Liangshui Nature Reserve of Yichun City, Heilongjiang Province, is a coniferous and broadleaved mixed forest. In this study, we assess the regeneration probability of coniferous saplings (CRP) in natural forests in 665 temporary plots in the Liangshui Nature Reserve. Using Sentinel-1 and Sentinel-2 images provided by the European Space Agency, as well as digital elevation model (DEM) data, we calculated the vegetation index, microwave vegetation index (RVI S1), VV, VH, texture features, slope, and DEM and combined them with field survey data to construct a logistic regression (LR) model, geographically weighted logistic regression (GWLR) model, random forest (RF) model, and multilayer perceptron (MLP) model to predict and analyze the CRP value of each pixel in the study area. The accuracy of the models was evaluated with the average values of the area under the ROC curve (AUC), kappa coefficient (KAPPA), root mean square error (RMSE), and mean absolute error (MAE) verified by five-fold cross-validation. The results showed that the RF model had the highest accuracy. The variable factor with the greatest impact on CRP was the DEM. The construction of the GWLR model considered more spatial factors and had a lower residual Moran index value. The four models had higher CRP prediction results in the low-latitude and low-longitude regions of the study area, and in the high-latitude and high-longitude regions of the study area, most pixels had a CRP value of 0 (i.e., no coniferous sapling regeneration occurred). [ABSTRACT FROM AUTHOR]

Tree regeneration is a key demographic process influencing long‐term forest dynamics. It is driven by climate, disturbances, biotic factors and their interactions. Thus, predictions of tree regeneration are challenging due to complex feedbacks along the wide climatic gradients covered by most tree species. The stress gradient hypothesis (SGH) provides a framework for assessing such feedbacks across species ranges, suggesting that competition between trees is more frequent under favourable conditions, whereas reduced competition (i.e. positive interactions) is more likely under climatic stress. Moreover, tree life‐history strategies (LHS) may shed light on how and whether the SGH explains regeneration of different tree species.To address these topics, we developed statistical models based on >50,000 recruitment events observed for 24 tree species in an extensive permanent plot network (6540 plots from 299 unmanaged European temperate, boreal and subalpine forests) covering a wide climatic gradient.We found that the effects of Leaf Area Index (as a proxy for competition) on tree recruitment changed along climatic gradients but in a species‐specific manner. Competition predominates, with its intensity decreasing under stressful conditions for most species, as predicted by the SGH. However, positive interactions were only evident for a few species. Additionally, the ability of the SGH to explain patterns of competition and positive interactions across the gradients differed among species, with some differences and exceptions that may be related to varying LHS.Synthesis. Our study shows that competition between trees toward climatic stress decreases systematically but depends on species stress tolerance to climate and shade. These findings explain within‐ and between‐species differences in tree recruitment patterns in European temperate forests. Moreover, our findings imply that projections of forest dynamics along wide climatic gradients and under climate change must accommodate both competition and positive interactions, as they strongly affect rates of community turnover. [ABSTRACT FROM AUTHOR]

The production of argan seedlings in nurseries is considered a crucial step for the success of any argan forest regeneration program since it increases the rate of survival and growth. Therefore, the substrate and container play a vital role in argan seedling production, while the use of shade may improve soil moisture and decrease the water stress of the plant. This study aims to determine the effects of these factors and their interactions. For this, the effects of four shade levels (0%, 20%, 40%, and 80%) and six different compositions of the substrate, as well as four different sizes and forms of containers, on argan seedling production were studied for six months under greenhouse conditions, based on analyzing the leaf mineral elements and measuring morphological traits. According to the studied parameters, the results show that 0% and 40% of shade are, respectively, the best shade levels for growth, while the germination rate is higher only in an unshaded compartment (85.28%). Furthermore, the substrate based on peat moss lead to one of the higher germination rates (78.75%) and the finest plants in terms of chlorophyll content, and shoot and root growth, while the largest container (C2) had the best shoot and root growth with 34.34 cm of root length. However, the mineral analysis, mainly the leaf total nitrogen concentration, is correlated with morphological traits. In addition, the cost–benefit analysis study confirmed this finding and valorizes the use of S1 substrate (1/2 black peat and 1/2 blond peat) and a C2 container (volume: 3100 mL) since it is considered the most efficient and economic combination for different shade levels. [ABSTRACT FROM AUTHOR]

In the dry areas of western Africa, the over-exploitation of forestry resources and the lack of tree regeneration lead to the degradation of agroforestry parklands. Such parklands could be better managed if the multiple services provided by the trees were well identified and valorized. However, there is little information on the local knowledge of' tree species regarding their functions, uses and services. Likewise, local stakeholders' perceptions of the relation between the species aptness for the above functions and uses and their functional traits is not well known. This study focuses on local knowledge of tree species in parklands of the Segou region in Mali, in order to identify specific uses or multifunctionalities that could be highlighted in improving agroforestry systems. Qualitative surveys have been carried out to identify users' perceptions of tree functions and functional traits. Findings show the possibility of classifying species by relevant functional groups, i.e. woody/timber trees, fruit/cash crop trees and trees related to livestock. Functional traits were not easily identified by farmers and the related information was difficult to analyze. Moreover, the perception of functions and traits depended on user groups (craftsmen, crop farmers, livestock farmers, traditional health practitioners, women etc.) and on agro-environmental and socio-economic contexts (activities, knowledge, means and practices). Therefore, scientific databases composed of lists of functions and traits for a given species have no generic value and must be valued depending on the context which may or may not enhance the substitutions between species for each use. [ABSTRACT FROM AUTHOR]

Our study aimed to assess the impacts of varying forest gap sizes on the density, growth, and spatial patterns of seedlings and saplings in spruce (Picea asperata) forests in the Saihanba region, Hebei Province, China. Twenty-four forest gaps were surveyed and categorized into six classes based on the gap size. A one-way ANOVA was used to compare differences in the density, height, and ground diameter of seedlings and saplings among six gap classes. Ripley's K function was used to explore the spatial patterns of regeneration establishment in each class. The findings of our study indicated that the forest gap size did not significantly influence the density of seedlings or the ground diameter growth of saplings, whereas it significantly influenced the height growth of saplings. In smaller gaps, natural regeneration occurred primarily in the gap edges. As the gap size increased, the natural generation began to shift from the edge areas to the gap centers. Large forest gaps had the highest percentages of random distribution patterns across all spatial scales. Aggregated distributions were observed at distances less than 1 m in all gap size classes, whereas uniform distributions tended to occur in the small gaps at distances of 2–4 m. Our findings indicated that larger forest gaps, ranging from 60 to 120 m2, were more conducive to spruce regeneration. The results can inform the development of targeted strategies for understory afforestation and the artificial promotion of natural regeneration in spruce forests. [ABSTRACT FROM AUTHOR]

Forest gaps induce environmental heterogeneity, but their effects on the local forest floor microbial communities are not fully understood. This research investigated the impact of forest gap positions on the forest floor microbial community composition to provide baseline information for projects to accelerate nutrient cycling and forest regeneration and enhance ecosystem services. A one-year-old forest gap and an area of 40–50 m2 in Pinus tabulaeformis plantations were selected in the Beijing mountainous area. Forest floor samples were collected from the following positions: gap center, gap border, and adjacent closed canopy. Our study demonstrated that gap positions significantly influenced the forest floor microbial community composition. The Gram-positive bacteria, Gram-negative bacteria, and total bacteria, as well as the fungi, were significantly greater in the forest gap center and gap border compared to those in the closed canopy, and the dissolved organic carbon, readily oxidized organic carbon, ammonia nitrogen, and nitrate nitrogen followed the same trend. Compared with those of the closed canopy, the Gram-positive bacteria, Gram-negative bacteria, total bacteria, and fungi in the gap center were markedly greater by 23%, 25%, 22%, and 24% and by 14%, 14%, 11%, and 16% in the gap border, respectively (p < 0.05). Redundancy analysis demonstrated that shifts in the litter microbial community composition were predominantly predicted by litter moisture and β-1,4-glucosidase. In addition, we discovered that the microbial community composition was greater in the undecomposed forest layer than that in the semi-decomposed layer. In summary, gap positions and forest floor layers have a significant impact on microbial community composition. Nevertheless, additional long-term investigations are needed. Our study provides a reference for the promotion of nutrient cycling to guide future ecological management. [ABSTRACT FROM AUTHOR]

The functional composition of plant communities (FCPC) makes a significant contribution to ecosystem properties, functions, and services. Here, we used 18 plant functional traits from the sPlot database v2.1 and the global forest management type dataset to explore the links between forest management and the FCPC. We used the post hoc Tukey test to explore the differences in the community-weighted mean (CWM) and community-weighted variance (CWV) among different forest management types [i.e., intact forests, managed forests with natural regeneration, planted forests, plantation forests (with up to a 15-year rotation), and agroforestry]. We found that different forest management types can result in significant variability in plant communities' functional composition. Plantation forests could result in significantly higher CWM and CWV compared to intact forests, and significant differences could occur between natural and managed forests with natural regeneration. Furthermore, the relationship between forest management practices and the FCPC depends on ecozone type changes. There were significant differences between natural and plantation forests for CWM and CWV in temperate forests. Our study provides an effective reference for applying plant functional traits to regulate and optimize the functions and services of forest ecosystems. [ABSTRACT FROM AUTHOR]