Forest Ecology and Management最新文献

{"title":"The abundance of microbial \"specific groups\" significantly influences downed log respiration","authors":"Lele Qi ,&nbsp;Jie Yuan ,&nbsp;Yiqi Wang ,&nbsp;Na Peng ,&nbsp;Lei Deng ,&nbsp;Roland Bol ,&nbsp;Shuoxin Zhang ,&nbsp;Josep Peñuelas","doi":"10.1016/j.foreco.2025.122703","DOIUrl":"10.1016/j.foreco.2025.122703","url":null,"abstract":"<div><div>Downed logs are an important component of the forest ecosystem, and the CO₂ released through their respiration is significant for global climate change and the carbon cycle. Respiration in downed logs primarily results from microbial metabolic activities. However, the mechanisms by which environmental factors regulate these activities remain unclear. Consequently, current models for carbon release from downed logs exhibit significant deviations. Therefore, this study investigates the same forest plots at 2013 and 2022 to measure the respiration rate (R_log), temperature, moisture, chemical element contents, and microbial community structure of downed logs from <em>Quercus aliena</em> var. <em>acuteserrata</em> and <em>Pinus tabulaeformis</em> at various decomposition stages (DSs). The aim is to elucidate the complex causal relationships and interdependencies among factors related to R_log. Key findings include: 1) R_log increases significantly with decomposition, with <em>Q. aliena</em> var. <em>acuteserrata</em> exhibiting a significantly higher average R_log (4.12 μmolCO₂·m⁻²·s⁻¹) than <em>P. tabulaeformis</em> (3.77 μmolCO₂·m⁻²·s⁻¹); 2) Significant differences in physicochemical properties of downed logs between 2013 and 2022, controlled by tree species and DSs, and the contents of moisture, N, P, Ca and Mg were significantly increased with the increase of DSs, while the content of K was significantly decreased (<em>p</em> &lt; 0.05); 3) In both 2013 and 2022, the dominant microorganisms in downed logs at different DSs included <em>Proteobacteria</em>, <em>Firmicutes</em>, <em>Actinobacteria</em>, <em>Acidobacteria</em>, <em>Bacteroidetes</em> (bacteria) and <em>Basidiomycota</em>, <em>Ascomycota</em> (fungi); 4<em>)</em> The abundance of microorganisms with significant difference between the two years (\"specific groups\"), including <em>Basidiomycota</em>, <em>Proteobacteria</em>, <em>Cyanobacteria</em> and <em>Chlamydiota</em>, etc, was closely correlated with R_log, although no significant correlation was found between microbial diversity indices and R_log; and 5) moisture emerged as the most influential factor on R_log, followed by Ca, Mg, K, P, N contents, and temperature, particularly in later DSs. These results suggest that future research on R_log mechanisms should focus on microorganisms with significant temporal and spatial abundance differences in downed logs. Furthermore, carbon emission models for downed logs should consider the combined effects of moisture and temperature on R_log, along with the mediating role of wood characteristics (species, DS, and chemical element contents), to improve the accuracy of future R_log predictions.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122703"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Afforestation increases glomalin-related soil protein content and enhances its association with stable soil carbon in karst regions","authors":"Lei Xie ,&nbsp;Qiumei Ling ,&nbsp;Peilei Hu ,&nbsp;Yuling Zhang ,&nbsp;Wei Zhang ,&nbsp;Yuan Zhao ,&nbsp;Kelin Wang","doi":"10.1016/j.foreco.2025.122704","DOIUrl":"10.1016/j.foreco.2025.122704","url":null,"abstract":"<div><div>Afforestation is widely regarded as a practical approach to enhance soil organic carbon (SOC) storage. Glomalin-related soil protein (GRSP), primarily produced by arbuscular mycorrhizal fungi, is vital for promoting SOC storage. However, the effects of afforestation on GRSP accumulation in bulk soil and the mineral-associated organic matter (MAOM) fraction, along with its relationship with mineral-associated organic carbon (MAOC), remains poorly understood, particularly in karst soils characterized by high mineral content. This study investigated these dynamics across six sites in the karst region of southwestern China, representing a broad climatic gradient. We collected 30 soil samples (0–10 cm) each from croplands and plantations along the gradient, analyzing SOC and GRSP content in both bulk soils and MAOM fractions. We found that afforestation significantly increased SOC by 58.1 % in bulk soils and 57.8 % in MAOM fractions, while MAOC rose by 63.2 %. The total GRSP content increased by 9.5 % in bulk soils and 10.8 % in MAOM fractions, compared to croplands, associated with higher soil nitrogen content and microbial biomass carbon after afforestation. However, the contribution of GRSP to SOC decreased after afforestation, likely due to increased plant-derived carbon inputs. Notably, GRSP contributed more to soil carbon in the MAOM fractions than in bulk soils across both croplands and plantations. Additionally, GRSP content showed a positively correlation with MAOC and SOC, suggesting a strong association with soil carbon stability. Furthermore, higher mean annual precipitation promoted GRSP accumulation, primary by increasing soil nutrient content. These findings highlight that while afforestation reduces the contribution of GRSP to SOC in karst regions, it enhances overall GRSP content, thereby increasing SOC stability. Furthermore, areas with higher precipitation offer greater potential for SOC stabilization through afforestation, though increased dissolved organic carbon leaching may temper this effect, providing valuable insights for carbon sequestration strategies in karst ecosystems.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122704"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mortality of retention trees due to blowdown damage in a retention forestry experiment in Hokkaido, northern Japan","authors":"Nobuhiro Akashi ,&nbsp;Akira Unno ,&nbsp;Akiko Nagasaka ,&nbsp;Yu Nagasaka ,&nbsp;Satoshi Yamanaka ,&nbsp;Yuichi Yamaura ,&nbsp;Kenichi Ozaki","doi":"10.1016/j.foreco.2025.122697","DOIUrl":"10.1016/j.foreco.2025.122697","url":null,"abstract":"<div><div>Retention forestry is an approach that preserves features of the forest structure which are important for maintaining biodiversity at harvest to mitigate the negative impacts of clearcutting by retaining trees. Since these trees are exposed to rapid environmental changes upon the harvesting of the trees around them, understanding the mortality patterns is crucial so that the application of retention forestry may meet its aims. In this study, the mortality of dispersed retention trees was assessed at the retention forestry experiment sites in Hokkaido, Japan, from pre-harvest to the 6th year post-harvest. Naturally regenerated broad-leaved trees were retained at three density levels (ca. 10, 50, and 100 trees/ha) at the final cutting of a planted <em>Abies sachalinensis</em> forest, and all retention trees were monitored. Most dead trees were uprooted or stem-broken, suggesting that blowdown caused by typhoons and extratropical cyclones was the major cause of mortality. After harvesting, the mortality of retention trees was higher at lower retention levels, and annual mortality rates at each site were higher in the first 3 years (1.1 %–7.6 %) than from the 3rd to 6th year (0.0 %–2.6 %). Trees with smaller diameters had higher mortality rates for all species except <em>Betula platyphylla</em>. The form of mortality (uprooted, stem-broken, standing dead) varied among species: species with low wood density were prone to stem-breakage, whereas shade-tolerant species had a low probability of uprooting and standing dead. Species with longer longevity were less prone to uprooting and stem breakage. Stem-broken <em>Tilia</em> spp. trees often survived and their crowns recovered, potentially providing a tree-related microhabitat of partially dead trunks and branches. Preventing blowdown damage is important both for the management of planted forests and to ensure the presence of large old trees long after harvesting. Severe wind damage is increasing due to climate change; hence, management measures that include wind damage will become crucial in northern temperate regions including Hokkaido. In planted conifer forests, mixing of wind-resistant broad-leaved trees may increase resistance to wind damage. We recommend retaining species that are resistant to blowdown and trees with large diameters and low height-diameter ratios. Additionally, some trees may be retained in small patches to avoid individual retention trees being directly exposed to the wind.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122697"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fuel loading after steep slope salvage logging in the southern Rocky Mountains","authors":"Mackenna R. Seaward ,&nbsp;Michelle C. Downey ,&nbsp;James M. Fischer ,&nbsp;Trace E. Martyn ,&nbsp;Ingrid C. Burke ,&nbsp;William K. Lauenroth ,&nbsp;Joseph N. Orefice","doi":"10.1016/j.foreco.2025.122669","DOIUrl":"10.1016/j.foreco.2025.122669","url":null,"abstract":"<div><div>Recent bark beetle outbreaks in western North America have raised concerns due to their frequency, impact, and geographic extent. These outbreaks can pose a heightened risk of intense wildfires by increasing the fuel load. In the Southern Rocky Mountain region, bark beetle outbreaks have led to millions of standing dead trees, prompting consideration of salvage treatments. Many of these treatments would occur on steep slopes using innovative harvesting equipment, such as winch-assisted cut-to-length harvesters, to remove standing dead stems. While salvage treatments aim to recover economic value and reduce fire risk, the ecological impacts from these treatments remain understudied, including what impact they have on wildfire woody fuel loading. Our study examined the impacts of winch-assisted cut-to-length salvage harvesting on fuel loads in subalpine and montane forest in southern Colorado. We assessed fuel loads in nine forest stands in treated and untreated areas and found that salvage logging significantly increased most fine woody surface fuels in both montane and subalpine forests. We also recorded a reduction of the standing dead fuels in montane and subalpine canopies by over 90 %. We did not observe significant differences in coarse woody material (CWM) loads for either forest type. Our results indicate that winch-assisted salvage logging may reduce the probability of canopy fires, while potentially increasing the risk of ground fires.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122669"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 10-year response of natural northern red oak reproduction to strip clearcutting an Appalachian hardwood stand","authors":"Patrick Plaugher,&nbsp;Jamie Schuler","doi":"10.1016/j.foreco.2025.122701","DOIUrl":"10.1016/j.foreco.2025.122701","url":null,"abstract":"<div><div>There are well-known difficulties associated with regenerating oak stands throughout the Central Hardwoods region. To successfully regenerate oak, competitive sources of advance reproduction are required ahead of harvesting—a condition that is rarely present, especially on productive sites. While treatments that enhance seedling competitiveness (<em>e.g.</em>, midstory removals, burning, competing vegetation control) are available, in practice, these are rarely implemented and/or effective because of high treatment costs and/or because they require delaying harvest.</div><div>As a potential alternative practice, we report the 10-yr results of a strip clearcut reproduction method that removes alternating 45.7 m wide strips across a mixed Appalachian hardwood forest, where the initial harvested strips provide timber revenue while simultaneously elevating understory light levels to increase oak seedling size within the residual strips to increase oak presence in a future harvest.</div><div>After 10 yr, we found that strip clearcutting facilitated the development of competitive northern red oak (<em>Quercus rubra</em> L.) advance reproduction within the residual strips. Northern red oak seedling densities (&gt;10,000 stems/ha) were greater than any other species. Northern red oak seedlings were most competitive within the interior 11.4 m positions in the residual strips, while the high densities of competitive northern red oak seedlings along the edges of the residual strips were also associated with competitive black birch (<em>Betula lenta</em> L.) and black cherry (<em>Prunus serotina</em> Ehrh.) reproduction. By contrast, in the cut strips, black birch and yellow-poplar (<em>Liriodendron tulipifera</em> L.) were the dominant stems and oaks were almost nonexistent.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122701"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leveraging remote sensing to distinguish closely related beech species in assisted gene flow scenarios","authors":"Gordana Kaplan ,&nbsp;Ariane Mora ,&nbsp;Katalin Csilléry ,&nbsp;Meredith C. Schuman","doi":"10.1016/j.foreco.2025.122700","DOIUrl":"10.1016/j.foreco.2025.122700","url":null,"abstract":"<div><div>European beech (<em>Fagus sylvatica L.</em>) forests are suffering under increasingly severe and frequent drought. Closely related beech species from Bulgaria, Asia Minor, the Caucasus, and Iran offer genetic resources for adaptive forest management strategies such as assisted migration (AM) and assisted gene flow (AGF) to enhance climate adaptation. However, due to similar morphology and leaf color, as well as hybridization in some cases, it is challenging to track the fate of introduced beech genotypes from these related species. Traditional identification methods relying on detailed morphological assessments and genetic testing are labor-intensive and costly, making them impractical for large-scale applications. This study evaluates the potential of high-resolution remote sensing to classify and monitor hybridizing beech species. Using multispectral data from PlanetScope SuperDove, we developed a remote sensing classification approach that captures phenological differences between the European beech <em>F. sylvatica</em> and co-planted Caucasian beech <em>(Fagus hohenackeriana Palibin),</em> two species capable of hybridization. Our method optimizes classification performance by focusing on key temporal windows and spectral features. We evaluated various machine learning algorithms with stratified spatial and temporal cross-validation on data from over 200 genetically classified individuals in two well-studied sites in France and Switzerland, where Caucasian beech was introduced over a century ago. The approach was further tested on three different study areas in Germany, where Caucasian beech was also planted in a known region but without individual tree coordinates. Key results show that our approach reveals distinct temporal and spectral differences during spring and autumn, corresponding with budbreak and senescence. Most algorithms achieved classification accuracies above 90 %. The algorithms effectively identified candidate zones for Caucasian beech within or near areas indicated by local foresters. This study demonstrates the potential of high-resolution multispectral satellite imagery and machine learning for classifying two closely related beech species in multiple locations where Caucasian beech was introduced to European beech forests. This classification is most accurate at the beginning or end of the growing season, likely due to phenological differences. By leveraging remote sensing, we provide a proof of concept for large-scale tracking of tree species introduction in AGF and AM scenarios, offering a valuable tool for adaptive forest management using Earth observation data.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122700"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trait-mediated neighborhood complementarity promotes tree growth in a temperate forest","authors":"Keda Cui ,&nbsp;Wei Xu ,&nbsp;Yan Geng ,&nbsp;Chunyu Zhang ,&nbsp;Bernhard Schmid ,&nbsp;Xiuhai Zhao","doi":"10.1016/j.foreco.2025.122689","DOIUrl":"10.1016/j.foreco.2025.122689","url":null,"abstract":"<div><div>Quantifying the effect of neighborhood functional composition on the performance of neighboring trees can help elucidate the processes of forest ecosystem formation. Traits may mediate niche and fitness differences of neighbors, as predicted by the niche-complementarity (absolute trait distance <em>ATD</em>, non-directional) and competitive-hierarchy (hierarchical trait distance <em>HTD</em>, directional) hypotheses. However, there is little understanding of the importance of these hypotheses in shaping neighborhood dynamics of forest tree communities, especially how trait-based niche complementarity and competitive hierarchy affect intra- and interspecific interactions, which regulate the growth of neighboring trees To address this knowledge gap, we conducted a field study in a temperate forest in China, focusing on <em>Pinus koraiensis</em> and <em>Ulmus laciniata</em>, two dominant tree species with distinct functional traits and resource-use strategies. <em>Pinus koraiensis</em> adopts a conservative strategy, characterized by functional traits such as slow resource-use efficiency and strong stress tolerance. In contrast, <em>Ulmus laciniata</em> employs an acquisitive strategy, typified by traits associated with high resource uptake and high environmental sensitivity. Our results showed that growth rates of both species increased with <em>ATD</em>, but not <em>HTD</em>. Specifically, interspecific complementarity (<em>ATD</em>_{<em>inter</em>}) positively influenced focal tree growth, whereas intraspecific complementarity (<em>ATD</em>_{<em>intra</em>}) did so only for the acquisitive species. Both <em>ATD</em>_{<em>inter</em>} and <em>ATD</em>_{<em>intra</em>} interacted with abiotic variables to affect the growth of acquisitive species, whereas the strength of the neighborhood complementarity effects did not vary with abiotic environment for the conservative species. Our findings suggest that the performance of individual trees may be regulated by neighborhood interactions that depend on intra- and interspecific trait differences, resource-use strategies, neighborhood density, and environmental conditions. This has implications for local or individual-based forest management, as well as for trait-based ecology from individual performance to forest ecosystem.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122689"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of Acacia invasive species in protected areas of Spain using PlanetScope high-resolution satellite images and machine learning models in time series: an important action for protective management of forests","authors":"Saeedeh Eskandari ,&nbsp;Carolina Acuña-Alonso ,&nbsp;Xana Álvarez","doi":"10.1016/j.foreco.2025.122696","DOIUrl":"10.1016/j.foreco.2025.122696","url":null,"abstract":"<div><div>Natural protected areas are important ecosystems in the world which provide valuable habitats for many unique fauna and flora. However, they have been destroyed by many natural and anthropogenic factors in recent years. One of the main destructive factors of forests in these ecosystems is the establishment of Invasive Plant Species (IPS). This study aims to map the forest area and <em>Acacia</em> sp. distribution (as the main IPS) in Cíes Islands in northwestern Spain using high resolution satellite images, and machine learning methods in time series. For this purpose, PlanetScope satellite images of the study area were obtained for June of 2016, 2020, and 2024. In addition, some data of location of tree species in forest cover and distribution of <em>Acacia</em> sp<em>.</em> were collected during fieldworks to use them as ground truth data. Four machine learning algorithms (RF, SVM, DT, and ANN) were used to separate the forest cover in time series. Results showed that Random Forest (RF) algorithm was the most accurate method to classify forest cover in the study area (for 2016, <em>OA</em>: 89.16 %, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.86; for 2020, <em>OA</em>: 93.33 %, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.91; for 2024, <em>OA</em>: 95.83 %, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.93). In addition, results demonstrated that the forest area increased in Cíes Islands during 8 years based on RF algorithm (2016: 129.99 ha, 2020: 134.05 ha, 2024: 135.45 ha). Results showed that the area of <em>Acacia</em> sp<em>.</em> increased about 28.01 % in these islands over 4 years (2016–2020) and then decreased about 21.31 % in following 4 years (2020–2024). Validation of <em>Acacia</em> sp<em>.</em> distribution maps showed that RF has effectively classified <em>Acacia</em> sp<em>.</em> in Cíes Islands in different years (for 2016, <em>OA</em>: 86.66 %, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.82; for 2020, <em>OA</em>: 90, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.87; for 2024, <em>OA</em>: 95 %, <span><math><mover><mrow><mi>k</mi></mrow><mo>ˆ</mo></mover></math></span>: 0.91). This study presented an innovative methodology that combined satellite imagery and machine learning models to provide the practical tools for forest managers against invasive plant species. The maps produced in this study facilitate the conservation of biodiversity inside protected areas in context of challenges of climate change.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122696"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hemlock woolly adelgid infestation influences canopy structural complexity and its relationship with primary production in a temperate mixed forest","authors":"Brandon C. Alveshere ,&nbsp;Tahrir Siddiqui ,&nbsp;Keith Krause ,&nbsp;Jan A.N. van Aardt ,&nbsp;Christopher M. Gough","doi":"10.1016/j.foreco.2025.122698","DOIUrl":"10.1016/j.foreco.2025.122698","url":null,"abstract":"<div><div>Forests and the ecosystem services they provide are increasingly threatened by exotic insect pests. Among these, hemlock woolly adelgid (HWA; <em>Adelges tsugae</em>) causes the decline and mortality of hemlocks (<em>Tsuga</em> spp.) in eastern North America, threatening to extirpate hemlock throughout much of its range. Effects of HWA on forest structure vary spatially and temporally and the resulting consequences for net primary production (NPP) are poorly understood. Here, we investigated the effects of HWA on canopy structural complexity (CSC), wood NPP, and their relationship in a temperate mixed forest. We hypothesized that CSC would be greater (<em>H1</em>) and wood production lower (<em>H2</em>) in more severely disturbed plots, and that effects of CSC would mediate disturbance-production relationships (<em>H3</em>). We found that higher levels of HWA infestation were broadly – but not unanimously – associated with greater structural complexity across multiple canopy strata (<em>H1</em>), as quantified by novel unmanned aerial system (UAS)-lidar metrics. In contrast to our expectations, tree mortality during the two-year measurement window was relatively low and did not directly reduce wood production (<em>H2</em>). Rather, wood production was independently coupled with mid- and whole-canopy CSC (R² = 0.96), driven in part by HWA. However, we were unable to conclude from our analysis that significant relationships between CSC and wood NPP were mediated by HWA’s effect on canopy structure (<em>H3</em>). Results overall suggested that HWA may generate structural complexity in the near-term through tree damage and mortality, but that the relationship between CSC and NPP may not be, or is only weakly, mediated by HWA, at least when mortality rates are low. Furthermore, the high degree of variance in wood NPP explained by CSC metrics derived from airborne lidar suggests they have potential utility for modeling and monitoring NPP in temperate forests.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122698"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rise and fall of a spruce bark beetle outbreak – Importance of colonisation density and reproductive success","authors":"Martin Schroeder ,&nbsp;Jonas Knape ,&nbsp;Simon Kärvemo","doi":"10.1016/j.foreco.2025.122695","DOIUrl":"10.1016/j.foreco.2025.122695","url":null,"abstract":"<div><div>Tree-killing bark beetles are an important disturbance factor in conifer forests. We studied if bark beetle performance in colonised trees may influence outbreak progression. Trees colonised by the Eurasian spruce bark beetle <em>Ips typographus</em> were sampled during an entire outbreak triggered by a storm-felling in southern Sweden. The study was conducted at nine storm gaps where no sanitation cuttings were done. Colonisation density (maternal gallery density) and reproductive success (daughters per mother) of <em>I. typographus</em>, and densities of competitors and enemies, were recorded from bark samples collected in the autumn from colonised storm-felled and standing trees during seven years. Yearly colonisation densities were much lower in storm-felled (68 – 103 galleries per m²) than in standing trees (218 – 717 galleries per m²). For standing trees the lowest colonisation densities occurred in the first two years of the outbreak and colonisation density was positively related to tree diameter. Beetle reproductive success was higher in storm-felled (9.4 – 9.6 daughters per mother) than in standing trees (0.4 – 5.7 daughters per mother). In standing trees the highest values occurred in the first two years of the outbreak. Reproductive success was significantly related to colonisation density (negatively), tree diameter (positively), parasitoid density (negatively at high densities) and attack year (negatively). Colonisation density had the largest effect. Our results demonstrate the importance of managing spruce forest in a way that increases tree vitality and minimises the risk for storm-fellings. Timely sanitation cuttings of colonised storm-felled and low-vitality standing trees may reduce the risk for outbreak initiations.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"586 ","pages":"Article 122695"},"PeriodicalIF":3.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}