Agricultural and Forest Meteorology最新文献

{"title":"Die-off after an extreme hot drought affects trees with physiological performance constrained by a more stressful abiotic niche","authors":"Guillermo Gea-Izquierdo ,&nbsp;Macarena Férriz ,&nbsp;Maria Conde ,&nbsp;Michael N. Evans ,&nbsp;Jose I. Querejeta ,&nbsp;Dario Martin-Benito","doi":"10.1016/j.agrformet.2025.110430","DOIUrl":"10.1016/j.agrformet.2025.110430","url":null,"abstract":"<div><div>Forest die-off has become more frequent under climate change, making crucial to understand the physiological mechanisms of forest mortality. We analyzed <em>Quercus ilex</em> die-off after a record-setting hot drought in two open woodlands without previous signs of decline. To understand physiological performance of trees we compared observations of radial growth dynamics, xylem hydraulic architecture, sapwood nutrient content and <span><math><mi>δ</mi></math></span>¹³C and <span><math><mrow><msup><mrow><mi>δ</mi></mrow><mn>18</mn></msup><mrow><mi>O</mi></mrow><mspace></mspace></mrow></math></span> in wood cellulose, with model simulations of tree carbon and water fluxes. We also assessed climate-growth responses across a <em>Q. ilex</em> network including sites with and without increased mortality. Past extreme droughts triggered multidecadal growth declines consistently in dead trees, which suggests long-term vulnerability of dead <em>Q. ilex</em> independent of the mortality process or causal factor. In the two studied woodlands, trends in xylem cellulose <span><math><mrow><msup><mrow><mi>δ</mi></mrow><mn>18</mn></msup><mi>O</mi></mrow></math></span> suggest that both dead and surviving trees increasingly relied on deeper water sources as stress increased under climate change. Dead and surviving trees followed different functional strategies reflecting chronic abiotic niche-related differences in stress. Dead trees invested similar or larger amounts of carbon in xylem reservoir tissues and less in xylem conductive tissues compared to surviving trees, yet exhibited an impaired nutrient status. Xylem hydraulic architecture differed in surviving and dead trees. The latter formed more efficient xylems with higher vessel density and larger or similar vessel sizes. The isotopic proxies suggested that dead trees systematically maintained tighter stomatal regulation and were forced to rely on deeper water likely sourced from the fractured granite bedrock. Isotopic proxies and simulations of water and carbon dynamics further suggest that surviving trees benefitted from soils with higher water-holding capacity contributing to buffer water stress. Dead trees expressed a functional paradox. Although their long-term functional strategy successfully coped with higher baseline water stress, they failed to withstand the additional increase in stress during an unprecedented hot drought.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110430"},"PeriodicalIF":5.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Canopy cover at the crown-scale best predicts spatial heterogeneity of soil moisture within a temperate Atlantic forest","authors":"Eva Meijers ,&nbsp;Roos Groenewoud ,&nbsp;Jorad de Vries ,&nbsp;Jens van der Zee ,&nbsp;Gert-Jan Nabuurs ,&nbsp;Marleen Vos ,&nbsp;Frank Sterck","doi":"10.1016/j.agrformet.2025.110431","DOIUrl":"10.1016/j.agrformet.2025.110431","url":null,"abstract":"<div><div>Managing forest openness can enhance drought resilience during dry, hot summer periods by reducing competition for soil moisture among trees. The purpose of our study was to better understand how different components of forest structure influence soil moisture variability. In our study, we utilized Terrestrial Laser Scanning to quantify the relationships between five forest structural attributes and the spatial distribution of soil moisture within experimental forest plots dominated by Douglas fir, Scots pine, and common beech in The Netherlands. In these plots the canopy openness ranged from 0, 20, 80 to 100 %. Observations were conducted during the hot and dry summer of 2022. Our findings revealed that all forest structural attributes related negatively with soil moisture and that the <em>crown features</em> canopy cover and plant area index predicted between 30 and 60 % of the spatial variability of soil moisture. In addition, these <em>crown features</em> consistently predicted 17 % more variation than the <em>trunk-centred</em> features basal area, stem density, and a density-dependent competition index. The <em>crown</em>-scale, corresponding to the crown radius of the dominant tree species, consistently explained most variation in soil moisture across species and time. We expect that tree water uptake is the primary factor influencing the spatial variability of soil moisture, rather than throughfall or interception, yet direct measurements of these processes are needed to substantiate this. This study suggests that forest management could benefit from information on forest structural attributes to guide tree harvest and improve soil moisture availability, contributing to developing a climate-smart forest management strategy.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110431"},"PeriodicalIF":5.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143192422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Invasive tree species benefit from ecohydrological niche segregation and deeper soil water uptake in a Mediterranean riparian forest","authors":"E Granda ,&nbsp;V Resco de Dios ,&nbsp;P Castro-Díez","doi":"10.1016/j.agrformet.2025.110433","DOIUrl":"10.1016/j.agrformet.2025.110433","url":null,"abstract":"<div><div>Aridification due to climate change and water table lowering due to human management are intensifying the environmental filter of summer aridity for Mediterranean riparian forests. This may represent an opportunity for the entry of non-native (NNT) species which might be pre-adapted to these new conditions, thus favoring their invasive potential. Differences in water uptake depth by coexisting native (NT) and NNT tree species could be one of the reasons why some of the latter species might become successful invaders in riparian ecosystems. To test whether spatial ecohydrological niche segregation occurs during dry summers, we analyzed stable water isotopes from different sources in a riparian ecosystem of central Spain. Xylem water δ¹⁸O was analyzed in 6 NT and 6 NNT (2 of them invasive) coexisting tree species. We used Bayesian isotope mixing models to estimate the proportion of water from different depths used by trees. We also tested the relationship between the δ¹⁸O from xylem water and leaf δ¹³C to test if species with deeper access to water have lower intrinsic water use efficiency (iWUE). We found no segregation between NT and NNT species in water uptake depth, but a species-specific vertical partitioning of water resources, with both invasive species extracting more water from the deepest soil layers<em>.</em> NNT species had higher leaf δ¹³C. A negative relationship between xylem water δ¹⁸O and leaf δ¹³C was found at interspecific level, indicating that species with greater access to deep water are also those bearing higher iWUE. Our results indicate a pronounced niche partitioning promoting species coexistence. The ability of invasive species to tap into deeper water layers combined with higher iWUE led to a competition-avoidance strategy together with a water stress-avoidance strategy. Deeper water uptake and greater iWUE could be important driving the success of tree species in Mediterranean floodplains under drier conditions.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110433"},"PeriodicalIF":5.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143228560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slow recovery of microclimate temperature buffering capacity after clear-cuts in boreal forests","authors":"Iris Starck ,&nbsp;Juha Aalto ,&nbsp;Steven Hancock ,&nbsp;Sauli Valkonen ,&nbsp;Leena Kalliovirta ,&nbsp;Eduardo Maeda","doi":"10.1016/j.agrformet.2025.110434","DOIUrl":"10.1016/j.agrformet.2025.110434","url":null,"abstract":"<div><div>The majority of Fennoscandian boreal forests are managed. Forest management inherently changes the physical structure of forests, thus altering ecosystem functions and the conditions for living organisms within these environments. However, the impacts of management on the microclimate buffering of boreal forests have not been comprehensively studied, despite that microclimate is one of the key determinants of biodiversity. Here, we studied the effect of forest structure and management on the temperature buffering capacity of boreal forests using terrestrial laser scanning and microclimate measurements. We measured the temperature variability on forest plots representing two management types: even-aged rotation forestry and uneven-aged forestry. To quantify buffering, we calculated the slope coefficient of the linear regression between microclimate and clear-cut temperatures. We found that the total amount of plant material alone was not an adequate predictor of the buffering. Instead, increasing canopy layers and the density of the understory led to more buffered temperature variability compared to clear-cuts and forests with fewer layers. The buffering was high in both mature even-aged and uneven-aged sites, but the effect in even-aged forests depended on stand age, suggesting that a strong buffering capacity could be reached only after approximately 30 years after clear-cut. In uneven-aged stands, the buffering capacity varied with recurring partial selection cuttings, but never lead to a full coupling with open-air temperatures like in even-aged stands after clear-cuts. We conclude that despite the buffering being on average stronger in mature even-aged stands than in uneven-aged stands, it can take decades for a clear-cut stand to reach the same buffering capacity as an uneven-aged forest with continuous tree cover, and it will eventually disappear after a new clear-cut harvest. From biodiversity perspective, uneven-aged management can create more temporally stable microclimatic conditions and can thus aid in maintaining microrefugia and mitigate climate warming impacts.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110434"},"PeriodicalIF":5.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143192611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Characterizing turbulence at a forest edge: A vorticity budget analysis around a canopy","authors":"Dorianis M. Perez ,&nbsp;Jesse M. Canfield ,&nbsp;Rodman R. Linn ,&nbsp;Kevin Speer","doi":"10.1016/j.agrformet.2025.110422","DOIUrl":"10.1016/j.agrformet.2025.110422","url":null,"abstract":"<div><div>Vorticity is a key characteristic of flow patterns that determine wildland fire behavior, frontal evolution, and wind-canopy interaction. Investigating the role of vorticity in the flow fields around vegetation can help us better understand fire-atmosphere feedback and the influences of vegetation on this feedback. In modeling vorticity, “perhaps the greatest knowledge gap exists in understanding which terms in the vorticity equation dominate [...] (and) when one or the other might dominate” (<span><span>Potter, 2012</span></span>). In this study, we investigate the role of vorticity in boundary layer dynamics and canopy/forest edge effects using HIGRAD/FIRETEC, a three-dimensional, two-phase transport model that conserves mass, momentum, energy, and chemical species. A vorticity transport equation was derived and discretized. Simulations were performed over a cuboidal homogeneous canopy surrounded by surface vegetation. This derivation led to the discovery of a drag tilting and stretching term, which shows that gradients in the aerodynamic drag of the vegetation, tied to heterogeneities in surface area-to-volume ratio, play an important role in the generation of vorticity. Results from the vorticity budget analysis show that the drag tilting and stretching term contributes significantly in the areas where these gradients are present, namely the edges of the canopy.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110422"},"PeriodicalIF":5.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143124403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Precipitation trends cause large uncertainties in grassland carbon budgets—a global meta-analysis","authors":"Hao Cui ,&nbsp;Lei Wang ,&nbsp;Zhiheng Du ,&nbsp;Zhiqiang Wei ,&nbsp;Cunde Xiao","doi":"10.1016/j.agrformet.2025.110432","DOIUrl":"10.1016/j.agrformet.2025.110432","url":null,"abstract":"<div><div>Continuous global warming exacerbates the worldwide hydrological cycle, and alterations in precipitation patterns affect the carbon cycle in grassland ecosystems. The consistency of grassland ecosystem responses to precipitation fluctuations remains unclear, despite extensive research on carbon cycling responses in various ecosystems. Here, we collected data from 109 studies (3129 observations in total) to assess the response of carbon cycle variables to precipitation changes in three grassland types (desert grassland, arid grassland, and wet grassland) at a global scale. The results show that the carbon cycle of grasslands had a wide asymmetric response to changes in precipitation. Increased precipitation promoted carbon input and carbon output in the three grassland types, whereas decreased precipitation inhibited both processes. The response of soil respiration (Rs) to increased precipitation was the lowest in the wet grassland (16.51 %) and the highest in the desert grassland (28.72 %), whereas the response to decreased precipitation was the highest in the arid grassland (-34 %) and the lowest in the wet grassland (-15.37 %). Interestingly, autotrophic respiration (Ra) responded more to increased precipitation than to decreased precipitation, with wet grasslands exhibiting a 10 times greater response. Moreover, the net ecosystem exchange (NEE) of arid grasslands responded more strongly to decreased precipitation, whereas the NEE of desert grasslands responded more strongly to increased precipitation. The natural climate of grasslands affected their response to precipitation management. As the treatment time increased, the response of soil respiration in the desert grasslands gradually decreased, whereas the response in the wet grasslands gradually increased. There was no significant temporal trend in arid grasslands. The natural climate of grassland ecosystems affected their response to precipitation treatments, particularly grassland moisture conditions, which may be the main limiting factor regulating the response of grassland ecosystems to the carbon cycle.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110432"},"PeriodicalIF":5.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An integrated, multivariate characterisation of water and photothermal regimes for faba bean in Australia","authors":"James B Manson ,&nbsp;Matthew D Denton ,&nbsp;Lachlan Lake ,&nbsp;Victor O Sadras","doi":"10.1016/j.agrformet.2025.110426","DOIUrl":"10.1016/j.agrformet.2025.110426","url":null,"abstract":"<div><div>Environmental characterisation provides a useful summary of a major source of variation in grain yield. Environments consist of water and photothermal regimes that covary in time and space, but previous characterisations have focussed on single-variable regimes such as drought, or downplayed the temporal pattern of multivariate regimes. Season-long, multivariate characterisations are needed to more realistically represent the complex growing conditions that crops encounter. We conducted two studies on faba bean, an important source of plant protein, in Australia, its largest exporter. From a database of yield with 299 variety trials, Study 1 tested the timing and strength of the association of seed yield with maximum and minimum temperature, heat stress, frost, solar radiation, vapour pressure deficit and simulated water supply:demand. Study 2 used cluster analysis of 30,096 simulated crops (1957–2022, three sowing dates, two varieties, 76 locations) to determine environment types for these variables, individually and combined. We tested the real-world relevance of the environment types with the seed yield data of Study 1. Water supply:demand, maximum temperature and vapour pressure deficit had the strongest links to grain yield in both studies. We identified four multivariate environment types that ranged from syndromes of ‘wet, cool and low evaporative demand’ to ‘dry, hot and high evaporative demand’. From least to most stressful environment type, median seed yield reduced by 62 %. Frequency of environment types varied with location, sowing date and variety, highlighting the potential value of earlier sowing and phenology for a large part of the country. From 1963–1992 compared with 1993–2022, the frequency of stressful environment types increased by 4 to 9 %, highlighting the need to adapt to a challenging future climate. Our findings can inform breeding, management and research of faba bean in Australia and beyond, and our multivariate method can be applied to other crops and environments.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110426"},"PeriodicalIF":5.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Dynamics of nonstructural carbohydrates during drought and subsequent recovery: A global meta-analysis","authors":"Zhaoguo Wang ,&nbsp;Chuankuan Wang","doi":"10.1016/j.agrformet.2025.110429","DOIUrl":"10.1016/j.agrformet.2025.110429","url":null,"abstract":"<div><div>The role of carbon starvation in drought-induced plant mortality remains a topic of debate. This underscores the need for a comprehensive understanding of the regulation of non-structural carbohydrates (NSCs) during drought and subsequent recovery. To this end, we compiled 226 articles and conducted a meta-analysis to examine the responses of NSCs to drought and rewatering, as well as the influences of plant functional type, drought magnitude, duration and climate variables. Overall, drought primarily reduced NSC concentrations in leaves, with negligible impacts on stems and roots. While starch concentrations declined, soluble sugar concentrations, including fructose and glucose, increased. Leaf NSC concentration returned to control levels after rewatering, whereas reductions in NSC concentrations in stems and roots were observed in the post-drought period. Herbaceous plants exhibited greater changes in leaf and root soluble sugar concentrations compared to woody plants. Gymnosperms experienced more significant root NSC reductions than angiosperms. Unlike deciduous angiosperms, evergreen angiosperms showed decreases in stem and root NSC concentrations during drought. Starch concentrations in mature woody plants remained relatively stable during drought, whereas they decreased in seedlings and saplings. The negative effects of drought on stem and root starch concentrations diminished with prolonged drought. Increases in soluble sugar concentrations in leaves were more pronounced in drier environments. These findings highlight the complex dynamics of NSCs during drought and subsequent recovery, emphasizing the need to consider plant functional types, drought characteristics, and climatic conditions when assessing the role of carbon starvation in drought-induced plant mortality.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110429"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Winter leaf reddening and photoprotection accessed by vegetation indices and its influence on canopy light-use efficiency of a Japanese cypress (Chamaecyparis obtusa) forest","authors":"Siyu Chen ,&nbsp;Yoshiko Kosugi ,&nbsp;Linjie Jiao ,&nbsp;Ayaka Sakabe ,&nbsp;Daniel Epron ,&nbsp;Tatsuro Nakaji ,&nbsp;Hibiki Noda ,&nbsp;Kouki Hikosaka ,&nbsp;Kenlo Nishida Nasahara","doi":"10.1016/j.agrformet.2025.110427","DOIUrl":"10.1016/j.agrformet.2025.110427","url":null,"abstract":"<div><div>Japanese cypress (<em>Chamaecyparis obtusa</em> Sieb<em>.</em> et Zucc.) is an evergreen conifer native to Japan and widely distributed in East Asia. Evergreen forests in temperate regions are usually exposed to high solar radiation and low temperatures during winter, a combination of stresses that can negatively impact leaf photosynthetic capacity. In response to excessive light energy stress under cold temperatures, Japanese cypress canopies exhibit a reversible color change associated with several photoprotective mechanisms known as “winter leaf reddening.” Here, several vegetation indices (VIs), including the photochemical reflectance index (PRI), rhodoxanthin index (RI), chlorophyll/carotenoid ratio index (CCI), triangular PRI index (tri-PRI), and red-green vegetation index (RGVI) were utilized to track the influence of winter leaf reddening and photoprotection on canopy-scale light-use efficiency (LUE) determined by the eddy covariance technique. Seasonal changes in VIs, environmental factors, and LUE in Japanese cypress canopies between 2017 and 2021 indicated that VIs could detect the phenology and LUE changes during winter leaf reddening. Our results suggest that winter leaf reddening occurrence is driven by prolonged low temperatures, and accompanied by dynamic xanthophyll cycle suppression, rhodoxanthin accumulation, and LUE reduction. Once stressful conditions are released, rhodoxanthin quickly decomposes and the remaining xanthophyll pigment may lead the canopy reddish-brown to persist longer. The integration of remote sensing and eddy covariance methods facilitates the validation of traditional results observed at the leaf scale within the context of the canopy scale, offering insights into how vegetation adjusts photosynthesis in response to environment stress.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110427"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"3D structural complexity of forest stands is determined by the magnitude of inner and outer crown structural attributes of individual trees","authors":"Alexandra Koller ,&nbsp;Matthias Kunz ,&nbsp;Maria D. Perles-Garcia ,&nbsp;Goddert von Oheimb","doi":"10.1016/j.agrformet.2025.110424","DOIUrl":"10.1016/j.agrformet.2025.110424","url":null,"abstract":"<div><div>Stand structural complexity influences various forest ecosystem functions, such as carbon storage or productivity. However, defining and measuring stand structural complexity is not trivial, as different structural attributes can be used to describe stand structure. We focus on a terrestrial laser scan-based stand structural complexity index (SSCI) and its components, mean fractal dimension (MeanFrac) and effective number of layers (ENL). These indices are now widely used, but there is still a lack of understanding of what exactly constitutes them. In this study, we analysed which structural attributes of individual trees determine these indices at which spatial scale. For our analysis, we used a high-resolution terrestrial laser scanning (TLS) dataset consisting of 11 structural attributes of over 1300 individual trees from 30 study plots of a young tree experiment in subtropical China. Our results show that averaged values of structural attributes of individual trees outperform values describing variation. Therefore, we suggest that SSCI, MeanFrac, and ENL depend on the magnitude rather than the variation of structural attributes among trees in a stand. We also found that SSCI is mainly determined by inner, i.e. branching intensity and branch number, and outer crown structure, i.e. crown compactness. MeanFrac is best described by branching intensity. Thus, a higher canopy space filling, i.e. higher density, leads to a higher stand structural complexity. Tree height and diameter at breast height are the main determinants of ENL. For the spatial scales we selected, only MeanFrac proved to be sensitive. The path analysis showed that different structural attributes (branching intensity vs. tree height) promote different aspects of stand structural complexity (horizontal vs. vertical), providing a variety of management options to increase stand structural complexity. Our results show that to better understand stand structural complexity, it is essential to include crown structural attributes in the assessment of stand structure.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"363 ","pages":"Article 110424"},"PeriodicalIF":5.6,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}