Pub Date : 2025-11-30DOI: 10.1016/j.agrformet.2025.110932
Hui Liu , Mingyu Wang , Pengle Cheng , Xiaodong Liu , Ying Huang
The increase in crop production has resulted in a significant increase in annual yield of crop straw. To analyze the impact of straw burning on air quality, this study integrates data on the burning of straw obtained from remote sensing satellites with meteorological data provided by meteorological satellites. Statistical analysis has been applied to analyze these data to identify patterns of the influence of straw burning pollutants on air quality. Experimental burnings were conducted to investigate the correlation between the volume of straw burning and the levels of particulate matter (PM). The findings demonstrate that under identical meteorological conditions, the impact of straw burning during the night is less pronounced than that of daytime burning, with pollutants dissipating more rapidly. Furthermore, the subsequent rainfall is found to mitigate the impact of straw burning on air quality. Consequently, the optimal strategy for minimizing the impact on air quality and accelerating the diffusion of pollutants is to conduct straw burning before predicted rainy weather and during nighttime on windy or sunny days.
{"title":"Meteorological drivers of air pollution impacts from straw burning in Henan Province, China","authors":"Hui Liu , Mingyu Wang , Pengle Cheng , Xiaodong Liu , Ying Huang","doi":"10.1016/j.agrformet.2025.110932","DOIUrl":"10.1016/j.agrformet.2025.110932","url":null,"abstract":"<div><div>The increase in crop production has resulted in a significant increase in annual yield of crop straw. To analyze the impact of straw burning on air quality, this study integrates data on the burning of straw obtained from remote sensing satellites with meteorological data provided by meteorological satellites. Statistical analysis has been applied to analyze these data to identify patterns of the influence of straw burning pollutants on air quality. Experimental burnings were conducted to investigate the correlation between the volume of straw burning and the levels of particulate matter (PM). The findings demonstrate that under identical meteorological conditions, the impact of straw burning during the night is less pronounced than that of daytime burning, with pollutants dissipating more rapidly. Furthermore, the subsequent rainfall is found to mitigate the impact of straw burning on air quality. Consequently, the optimal strategy for minimizing the impact on air quality and accelerating the diffusion of pollutants is to conduct straw burning before predicted rainy weather and during nighttime on windy or sunny days.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"378 ","pages":"Article 110932"},"PeriodicalIF":5.7,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625238","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}
Understanding how photosynthetic carbon (C) is allocated to woody biomass remains a critical gap in predicting forest responses to climate change, especially in cold-limited ecosystems, due to the pervasive lack of comprehensive carbon-based data at the whole-stand level. We applied a multi-proxy approach integrating eddy covariance, process-based modelling, and quantitative wood anatomy to assess C fluxes and stem-level C allocation in two mature boreal stands in Canada—black spruce (Picea mariana Mill.) and jack pine (Pinus banksiana Lamb.)—from 1999 to 2021.
At both stands, we found that stem structural C allocation (measured as cell wall area, CWA) was tightly coupled with observed and modelled gross primary productivity (GPP). Modelled non-structural carbohydrates (NSC) dynamics revealed contrasting temporal patterns between species: jack pine showed an immediate response to available NSC and annual CWA, suggesting an active role of NSC in supporting growth under fluctuating environmental conditions. In contrast, black spruce exhibited a delayed effect, suggesting a more passive and buffering role of NSC in stem structural C allocation. Notably, at the jack pine site, extreme cold years corresponded to reduced CWA alongside elevated NSC concentrations, which might indicate a shift in C allocation priorities toward storage over growth. Our findings, based on a multi-proxy approach, provide novel insights into species-specific and possible trade-offs between storage and growth, useful for improving C budget models and adaptive forest management under climate change.
{"title":"Decoding carbon allocation in boreal forests: Integrating multi-proxy observations and process-based modelling","authors":"Paulina F. Puchi , Daniela Dalmonech , Daniele Castagneri , Giancarlo Genovese , Warren Helgason , Myroslava Khomik , Lorenzo Brilli , Alessio Collalti","doi":"10.1016/j.agrformet.2025.110923","DOIUrl":"10.1016/j.agrformet.2025.110923","url":null,"abstract":"<div><div>Understanding how photosynthetic carbon (C) is allocated to woody biomass remains a critical gap in predicting forest responses to climate change, especially in cold-limited ecosystems, due to the pervasive lack of comprehensive carbon-based data at the whole-stand level. We applied a multi-proxy approach integrating eddy covariance, process-based modelling, and quantitative wood anatomy to assess C fluxes and stem-level C allocation in two mature boreal stands in Canada—black spruce (<em>Picea mariana</em> Mill.) and jack pine (<em>Pinus banksiana</em> Lamb.)—from 1999 to 2021.</div><div>At both stands, we found that stem structural C allocation (measured as cell wall area, CWA) was tightly coupled with observed and modelled gross primary productivity (GPP). Modelled non-structural carbohydrates (NSC) dynamics revealed contrasting temporal patterns between species: jack pine showed an immediate response to available NSC and annual CWA, suggesting an active role of NSC in supporting growth under fluctuating environmental conditions. In contrast, black spruce exhibited a delayed effect, suggesting a more passive and buffering role of NSC in stem structural C allocation. Notably, at the jack pine site, extreme cold years corresponded to reduced CWA alongside elevated NSC concentrations, which might indicate a shift in C allocation priorities toward storage over growth. Our findings, based on a multi-proxy approach, provide novel insights into species-specific and possible trade-offs between storage and growth, useful for improving C budget models and adaptive forest management under climate change.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"378 ","pages":"Article 110923"},"PeriodicalIF":5.7,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625239","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}
Pub Date : 2025-11-29DOI: 10.1016/j.agrformet.2025.110961
Xinhao Li , Tianshan Zha , Peng Liu , Xin Jia , Yun Tian , Hongxian Zhao , Jinshi Jian , Na Deng
Dryland ecosystems play a pivotal role in regulating both the trajectory and magnitude of the terrestrial carbon sink. Projections indicate that these regions will experience increasingly frequent and intense water stress. However, large uncertainties remain regarding the responses of carbon and water fluxes to these stresses in temperate semi-arid steppes. Here, we analyzed a decade of measurements (2014–2023) to examine the responses of carbon and water fluxes in the Mu Us Desert steppe ecosystem in northern China under three water stress conditions: dry, heat, and compound dry-heat conditions. Collectively, carbon and water fluxes decreased under water stress conditions, with net ecosystem production (NEP) shifting from a carbon sink of 0.39 ± 0.03 g C m-2 d-1 to a carbon source ranging from -0.43 to -0.28 g C m-2 d-1. Using an interpretable machine learning algorithm, we found that the responses of carbon and water fluxes to soil water content (SWC) exhibited a threshold effect characterized by a positive pattern. Below these threshold values, SWC’s impacts on the fluxes were negative, while exceeding these values resulted in positive effects. Under water stress conditions, both shallow-layer and whole-profile SWC constrained carbon and water fluxes due to their low levels. Similarly, elevated temperature under water stress conditions enhanced ecosystem respiration (Re) and evapotranspiration (ET), partially offsetting the constraints imposed by limited water availability. However, gross ecosystem production (GPP) and NEP exhibited contrasting response patterns to temperature, leading to a greater suppression of GPP and NEP compared to Re and ET under heat and dry-heat conditions. Our findings highlight the importance of the divergent temperature responses of photosynthesis and respiration in controlling the ecosystem carbon sink under water stress conditions. Ongoing climate warming and increasingly frequent water stress may impair the carbon sequestration potential of semi-arid steppes and thus exacerbate their vulnerability.
旱地生态系统在调节陆地碳汇的轨迹和规模方面发挥着关键作用。预测表明，这些地区将面临日益频繁和强烈的水资源压力。然而，在温带半干旱草原，碳通量和水通量对这些压力的响应仍然存在很大的不确定性。在此，我们分析了中国北方毛乌素沙漠草原生态系统在干旱、高温和复合干热三种水分胁迫条件下的碳通量和水通量的响应。总体而言，在水分胁迫条件下，碳通量和水通量减少，净生态系统产量（NEP）从0.39±0.03 g C m-2 d-1的碳汇转变为-0.43 ~ -0.28 g C m-2 d-1的碳源。利用可解释的机器学习算法，我们发现碳通量和水通量对土壤含水量（SWC）的响应表现出正模式的阈值效应。低于这些阈值，SWC对通量的影响为负，超过这些阈值则为正。在水分胁迫条件下，浅层和全剖面SWC均因其低水平而限制了碳和水通量。同样，在水分胁迫条件下，温度升高增强了生态系统呼吸（Re）和蒸散（ET），部分抵消了有限的水分供应所造成的限制。然而，在高温和干热条件下，生态系统总生产量（GPP）和NEP对温度的响应模式不同，GPP和NEP受到的抑制比Re和ET更大。我们的研究结果强调了在水分胁迫条件下光合作用和呼吸作用的不同温度响应在控制生态系统碳汇中的重要性。持续的气候变暖和日益频繁的水资源紧张可能损害半干旱草原的固碳潜力，从而加剧其脆弱性。
{"title":"Contrasting temperature responses of photosynthesis and respiration amplify reduction in carbon sink under water stress conditions in a temperate semi-arid steppe","authors":"Xinhao Li , Tianshan Zha , Peng Liu , Xin Jia , Yun Tian , Hongxian Zhao , Jinshi Jian , Na Deng","doi":"10.1016/j.agrformet.2025.110961","DOIUrl":"10.1016/j.agrformet.2025.110961","url":null,"abstract":"<div><div>Dryland ecosystems play a pivotal role in regulating both the trajectory and magnitude of the terrestrial carbon sink. Projections indicate that these regions will experience increasingly frequent and intense water stress. However, large uncertainties remain regarding the responses of carbon and water fluxes to these stresses in temperate semi-arid steppes. Here, we analyzed a decade of measurements (2014–2023) to examine the responses of carbon and water fluxes in the Mu Us Desert steppe ecosystem in northern China under three water stress conditions: dry, heat, and compound dry-heat conditions. Collectively, carbon and water fluxes decreased under water stress conditions, with net ecosystem production (<em>NEP</em>) shifting from a carbon sink of 0.39 ± 0.03 g C m<sup>-2</sup> d<sup>-1</sup> to a carbon source ranging from -0.43 to -0.28 g C m<sup>-2</sup> d<sup>-1</sup>. Using an interpretable machine learning algorithm, we found that the responses of carbon and water fluxes to soil water content (<em>SWC</em>) exhibited a threshold effect characterized by a positive pattern. Below these threshold values, <em>SWC</em>’s impacts on the fluxes were negative, while exceeding these values resulted in positive effects. Under water stress conditions, both shallow-layer and whole-profile <em>SWC</em> constrained carbon and water fluxes due to their low levels. Similarly, elevated temperature under water stress conditions enhanced ecosystem respiration (<em>R</em><sub>e</sub>) and evapotranspiration (<em>ET</em>), partially offsetting the constraints imposed by limited water availability. However, gross ecosystem production (<em>GPP</em>) and <em>NEP</em> exhibited contrasting response patterns to temperature, leading to a greater suppression of <em>GPP</em> and <em>NEP</em> compared to <em>R</em><sub>e</sub> and <em>ET</em> under heat and dry-heat conditions. Our findings highlight the importance of the divergent temperature responses of photosynthesis and respiration in controlling the ecosystem carbon sink under water stress conditions. Ongoing climate warming and increasingly frequent water stress may impair the carbon sequestration potential of semi-arid steppes and thus exacerbate their vulnerability.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110961"},"PeriodicalIF":5.7,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614105","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}
Pub Date : 2025-11-26DOI: 10.1016/j.agrformet.2025.110937
Yi Zhu , Guodong Han , Loïc Pellissier , Mai-He Li , Lin Jiang , Jinglei Tang , Cuiping Gao , Haiyan Ren
It is still unclear how increasing nitrogen (N) deposition, climate warming, and their interaction affect biotic impoverishment (decreases in α-diversity) and homogenization (decreases in β-diversity) of plant communities at taxonomic, functional, and phylogenetic levels. To address this, we conducted a long-term (17-year) field experiment in Inner Mongolia's temperate desert steppe to investigate the effects of warming and nitrogen deposition on plant taxonomic, functional, and phylogenetic α- and β-diversity. Over this period (2006–2022), warming (mean annual temperature + 1.4 °C) significantly decreased species richness and functional α-diversity throughout the experiment, whereas its effects on phylogenetic α-diversity and community phylogenetic structure were significant only before 2015 and disappeared thereafter, likely due to an extreme drought that reset the community composition. In contrast, β-diversity steadily declined over the entire period. These dynamics led to a shift in the community phylogenetic structure from overdispersion towards randomness during the first 10 years. Nitrogen addition (10 g m2 yr-1) had no significant impact on diversity at the functional and phylogenetic levels but increased β-diversity at the taxonomic level. Our findings reveal that relatively rare species were more likely to go extinct, while species with higher leaf nitrogen concentrations were more prone to colonization, and these patterns were observed across all treatments. These findings suggest that warming can contribute to biotic impoverishment and homogenization by causing the extinction of species distantly related to the resident community.
氮沉降增加、气候变暖及其相互作用如何在分类、功能和系统发育水平上影响植物群落的生物贫困化（α-多样性降低）和均质化（β-多样性降低），目前尚不清楚。为了解决这一问题，我们在内蒙古温带荒漠草原进行了长达17年的长期野外试验，研究了增温和氮沉降对植物分类、功能和系统发育α-和β-多样性的影响。2006-2022年期间，气候变暖（年均温度+ 1.4℃）显著降低了整个实验期间的物种丰富度和功能α-多样性，而对系统发育α-多样性和群落系统发育结构的影响仅在2015年之前显著，此后消失，可能是由于极端干旱重置了群落组成。相反，β-多样性在整个时期稳步下降。这些动态导致群落系统发育结构在前10年由过度分散转向随机。氮添加量（10 g m2 /年-1）在功能和系统发育水平上对多样性无显著影响，但在分类水平上增加了β-多样性。研究结果表明，相对罕见的物种更容易灭绝，而叶片氮浓度较高的物种更容易定植，并且这些模式在所有处理中都观察到。这些发现表明，气候变暖可以通过导致与居住社区远亲物种的灭绝来促进生物贫困化和同质化。
{"title":"Climate warming, rather than nitrogen deposition, reduces plant diversity and increases community homogenization in a desert steppe","authors":"Yi Zhu , Guodong Han , Loïc Pellissier , Mai-He Li , Lin Jiang , Jinglei Tang , Cuiping Gao , Haiyan Ren","doi":"10.1016/j.agrformet.2025.110937","DOIUrl":"10.1016/j.agrformet.2025.110937","url":null,"abstract":"<div><div>It is still unclear how increasing nitrogen (N) deposition, climate warming, and their interaction affect biotic impoverishment (decreases in α-diversity) and homogenization (decreases in β-diversity) of plant communities at taxonomic, functional, and phylogenetic levels. To address this, we conducted a long-term (17-year) field experiment in Inner Mongolia's temperate desert steppe to investigate the effects of warming and nitrogen deposition on plant taxonomic, functional, and phylogenetic α- and β-diversity. Over this period (2006–2022), warming (mean annual temperature + 1.4 °C) significantly decreased species richness and functional α-diversity throughout the experiment, whereas its effects on phylogenetic α-diversity and community phylogenetic structure were significant only before 2015 and disappeared thereafter, likely due to an extreme drought that reset the community composition. In contrast, β-diversity steadily declined over the entire period. These dynamics led to a shift in the community phylogenetic structure from overdispersion towards randomness during the first 10 years. Nitrogen addition (10 g m<sup>2</sup> yr<sup>-1</sup>) had no significant impact on diversity at the functional and phylogenetic levels but increased β-diversity at the taxonomic level. Our findings reveal that relatively rare species were more likely to go extinct, while species with higher leaf nitrogen concentrations were more prone to colonization, and these patterns were observed across all treatments. These findings suggest that warming can contribute to biotic impoverishment and homogenization by causing the extinction of species distantly related to the resident community.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110937"},"PeriodicalIF":5.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598740","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}
Pub Date : 2025-11-26DOI: 10.1016/j.agrformet.2025.110959
Yuxin Liu , Xiaofei Yan , Taisheng Du , Ricardo F. de Oliveira , Keyi Zhang , Qiang Cheng
In temperate and cold regions, woody plants freeze at low temperatures, seriously affecting the growth and distribution of trees. Radial location (RL) dynamics of freeze-thaw front in tree stems can directly and efficiently reflect the freezing and thawing processes of woody plants. Two previous approximate models (Sun et al., 2019; Zhao et al., 2021) were proposed and combined with electromagnetic (EM) sensors to track the RL dynamics. However, the two models neglected the crucial influences stemming from non-uniformity of stem water content (StWC) distribution and electric-field (E-field) attenuation of EM sensor for measuring StWC. In this study, we proposed a comprehensive model to track the RL dynamics by involving the non-uniformity of StWC distribution and E-field attenuation, which is more universal under practical conditions. If the E-field and StWC are assumed to be uniform, the two approximate models can be derived from our comprehensive model. We calculated the RL using the comprehensive model by numerical methods in Python and the data from the field reported by Sun et al. (2019). The results showed that the RLs calculated using the previous approximate models were underestimated in comparison with that using the proposed model at the early stage of freezing or thawing process. At the late stage of freezing or thawing process, they were overestimated. This is because the radial distribution of StWC and E-field are not uniform under practical conditions. The above conclusion is also feasible when tracking the RL dynamics using the extended data. When the stem was completely frozen or thawed, the RLs calculated using the three models have the same value. For investigating the freeze-thaw status of trees in temperate and cold regions, the measurement of StWC distribution and E-field attenuation of EM sensor should be taken into account to accurately track the RL dynamics.
在温带和寒冷地区，木本植物在低温下冻结，严重影响树木的生长和分布。树干冻融锋的径向定位动态可以直接有效地反映木本植物的冻融过程。之前提出了两个近似模型（Sun et al., 2019; Zhao et al., 2021），并将其与电磁（EM）传感器相结合，以跟踪RL动态。然而，这两种模型都忽略了茎干含水量分布的不均匀性和测量茎干含水量时电磁传感器的电场衰减对茎干含水量的重要影响。在本研究中，我们提出了一个综合的模型来跟踪RL动态，该模型考虑了StWC分布的不均匀性和e场衰减，在实际条件下更具有普适性。如果假设e场和StWC是均匀的，则可以从我们的综合模型中导出两个近似模型。我们使用Python中的数值方法和Sun等人（2019）报告的现场数据使用综合模型计算RL。结果表明，在冻融过程的早期阶段，使用先前的近似模型计算的RLs与使用本文模型计算的RLs相比被低估了。在冷冻或解冻过程的后期，它们被高估了。这是因为在实际条件下，StWC和E-field的径向分布并不均匀。当使用扩展数据跟踪RL动态时，上述结论也是可行的。当茎干完全冻结或完全解冻时，使用三种模型计算的RLs值相同。为了研究温带和寒区树木冻融状态，应考虑测量StWC分布和EM传感器的e场衰减，以准确跟踪RL动态。
{"title":"Accurately tracking radial location dynamics of freeze-thaw front in tree stems under field conditions: a comprehensive model considering non-uniformity of stem water content distribution and electric-field attenuation of electromagnetic sensor","authors":"Yuxin Liu , Xiaofei Yan , Taisheng Du , Ricardo F. de Oliveira , Keyi Zhang , Qiang Cheng","doi":"10.1016/j.agrformet.2025.110959","DOIUrl":"10.1016/j.agrformet.2025.110959","url":null,"abstract":"<div><div>In temperate and cold regions, woody plants freeze at low temperatures, seriously affecting the growth and distribution of trees. Radial location (RL) dynamics of freeze-thaw front in tree stems can directly and efficiently reflect the freezing and thawing processes of woody plants. Two previous approximate models (Sun et al., 2019; Zhao et al., 2021) were proposed and combined with electromagnetic (EM) sensors to track the RL dynamics. However, the two models neglected the crucial influences stemming from non-uniformity of stem water content (StWC) distribution and electric-field (E-field) attenuation of EM sensor for measuring StWC. In this study, we proposed a comprehensive model to track the RL dynamics by involving the non-uniformity of StWC distribution and E-field attenuation, which is more universal under practical conditions. If the E-field and StWC are assumed to be uniform, the two approximate models can be derived from our comprehensive model. We calculated the RL using the comprehensive model by numerical methods in Python and the data from the field reported by Sun et al. (2019). The results showed that the RLs calculated using the previous approximate models were underestimated in comparison with that using the proposed model at the early stage of freezing or thawing process. At the late stage of freezing or thawing process, they were overestimated. This is because the radial distribution of StWC and E-field are not uniform under practical conditions. The above conclusion is also feasible when tracking the RL dynamics using the extended data. When the stem was completely frozen or thawed, the RLs calculated using the three models have the same value. For investigating the freeze-thaw status of trees in temperate and cold regions, the measurement of StWC distribution and E-field attenuation of EM sensor should be taken into account to accurately track the RL dynamics.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110959"},"PeriodicalIF":5.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145609517","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}
Pub Date : 2025-11-26DOI: 10.1016/j.agrformet.2025.110954
Jing Ren , Shuai Fang , Guangyou Hao , Fei Lin , Ji Ye , Zhanqing Hao , Xugao Wang , Claire Fortunel
Climate change is intensifying the occurrence of hydric events, such as summer water availability and winter freeze-thaw cycles, which are increasingly significant in temperate regions. These events pose substantial threats to tree hydraulic functions and thereby limiting tree growth. In this study, we investigated the compound effects of climate-induced stressors and neighborhood crowding on tree growth, and tested how species functional traits mediate these responses. We combined annual growth data over 8 years from 593 individuals representing 20 tree species in Northeast China to evaluate the relative influence of water availability, freeze-thaw cycles, and their interaction with local crowding on tree growth, and how species functional traits mediate these responses. Our findings indicate that tree growth declined with increasing freeze-thaw cycles frequency, whereas summer water availability had no detectable effect. Tree growth was limited by neighborhood crowding, which appeared to operate largely independently of freeze-thaw cycles. In addition, species with higher xylem hydraulic efficiency, lower wood density and lower specific leaf area grew faster and were more sensitive to freeze-thaw cycles, while species with higher xylem hydraulic efficiency were less sensitive to neighborhood crowding. Our results demonstrate distinct and independent roles of freeze-thaw cycles and neighborhood crowding in shaping temperate tree growth, suggesting that considering the freeze-thaw cycles may improve predictions of temperate forest dynamics facing altered climate changes. Furthermore, species traits can capture how temperate trees cope with different stressors, highlighting the importance of integrating functional traits for a more comprehensive understanding of tree responses to environmental stressors.
{"title":"Functional traits shape tree growth response to winter freeze-thaw cycle and neighborhood crowding in humid temperate forests","authors":"Jing Ren , Shuai Fang , Guangyou Hao , Fei Lin , Ji Ye , Zhanqing Hao , Xugao Wang , Claire Fortunel","doi":"10.1016/j.agrformet.2025.110954","DOIUrl":"10.1016/j.agrformet.2025.110954","url":null,"abstract":"<div><div>Climate change is intensifying the occurrence of hydric events, such as summer water availability and winter freeze-thaw cycles, which are increasingly significant in temperate regions. These events pose substantial threats to tree hydraulic functions and thereby limiting tree growth. In this study, we investigated the compound effects of climate-induced stressors and neighborhood crowding on tree growth, and tested how species functional traits mediate these responses. We combined annual growth data over 8 years from 593 individuals representing 20 tree species in Northeast China to evaluate the relative influence of water availability, freeze-thaw cycles, and their interaction with local crowding on tree growth, and how species functional traits mediate these responses. Our findings indicate that tree growth declined with increasing freeze-thaw cycles frequency, whereas summer water availability had no detectable effect. Tree growth was limited by neighborhood crowding, which appeared to operate largely independently of freeze-thaw cycles. In addition, species with higher xylem hydraulic efficiency, lower wood density and lower specific leaf area grew faster and were more sensitive to freeze-thaw cycles, while species with higher xylem hydraulic efficiency were less sensitive to neighborhood crowding. Our results demonstrate distinct and independent roles of freeze-thaw cycles and neighborhood crowding in shaping temperate tree growth, suggesting that considering the freeze-thaw cycles may improve predictions of temperate forest dynamics facing altered climate changes. Furthermore, species traits can capture how temperate trees cope with different stressors, highlighting the importance of integrating functional traits for a more comprehensive understanding of tree responses to environmental stressors.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110954"},"PeriodicalIF":5.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145609516","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}
Pub Date : 2025-11-25DOI: 10.1016/j.agrformet.2025.110888
Yin Wang , Xiaojuan Tong , Jinsong Zhang , Jun Li , Ping Meng , Weifeng Wang , Yating Wang , Mingxin Yang , Qingyuan Liu
Forest ecosystem photosynthesis is primarily driven by hydrothermal conditions. However, the effects of hydrothermal integration and synergy on carbon exchange across forest ecosystems are still not clear. We examined the divergence of carbon exchange over 16 forest ecosystems in eastern China. To explore the controls of hydrothermal change on gross primary productivity (GPP), ecosystem respiration (Re), and net ecosystem productivity (NEP), we developed two indices for hydrothermal integration (TP) and hydrothermal synergy (D) based on the copula function. Compared with traditional indices such as the water and thermal product index (K), aridity index (AI), and standardized precipitation evapotranspiration index (SPEI), TP and D demonstrated higher sensitivity and applicability in capturing seasonal and spatial variations in hydrothermal conditions. Vapor pressure deficit (VPD), soil water content (SWC), and AI responded nonlinearly to TP and D, with coordinated hydrothermal conditions enhancing SWC and uncoordinated or scarce conditions increasing drought risk. TP and D explained over 80% of the variability in GPP, Re, and NEP, which better captured hydrothermal controls on carbon exchange than temperature and precipitation alone. Carbon fluxes peaked at TP ≈ 1 and D slightly above 0, indicating that moderately water-dominated hydrothermal synergy provided optimal conditions for photosynthesis and respiration. Random forest analysis revealed that SWC was the primary driver of GPP, Re, and NEP, followed by D for GPP and NEP, indicating that forest carbon exchange is mainly regulated by soil water availability and atmospheric hydrothermal synergy. This study clarifies how hydrothermal conditions impact on carbon exchange in forest ecosystems and provides insights into assessing forest responses to climate change.
{"title":"Hydrothermal integration and synergy regulate carbon exchange in forest ecosystems of eastern China","authors":"Yin Wang , Xiaojuan Tong , Jinsong Zhang , Jun Li , Ping Meng , Weifeng Wang , Yating Wang , Mingxin Yang , Qingyuan Liu","doi":"10.1016/j.agrformet.2025.110888","DOIUrl":"10.1016/j.agrformet.2025.110888","url":null,"abstract":"<div><div>Forest ecosystem photosynthesis is primarily driven by hydrothermal conditions. However, the effects of hydrothermal integration and synergy on carbon exchange across forest ecosystems are still not clear. We examined the divergence of carbon exchange over 16 forest ecosystems in eastern China. To explore the controls of hydrothermal change on gross primary productivity (GPP), ecosystem respiration (<em>R</em>e), and net ecosystem productivity (NEP), we developed two indices for hydrothermal integration (TP) and hydrothermal synergy (D) based on the copula function. Compared with traditional indices such as the water and thermal product index (K), aridity index (AI), and standardized precipitation evapotranspiration index (SPEI), TP and D demonstrated higher sensitivity and applicability in capturing seasonal and spatial variations in hydrothermal conditions. Vapor pressure deficit (VPD), soil water content (SWC), and AI responded nonlinearly to TP and D, with coordinated hydrothermal conditions enhancing SWC and uncoordinated or scarce conditions increasing drought risk. TP and D explained over 80% of the variability in GPP, <em>R</em>e, and NEP, which better captured hydrothermal controls on carbon exchange than temperature and precipitation alone. Carbon fluxes peaked at TP ≈ 1 and D slightly above 0, indicating that moderately water-dominated hydrothermal synergy provided optimal conditions for photosynthesis and respiration. Random forest analysis revealed that SWC was the primary driver of GPP, <em>R</em>e, and NEP, followed by D for GPP and NEP, indicating that forest carbon exchange is mainly regulated by soil water availability and atmospheric hydrothermal synergy. This study clarifies how hydrothermal conditions impact on carbon exchange in forest ecosystems and provides insights into assessing forest responses to climate change.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110888"},"PeriodicalIF":5.7,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145593689","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}
Pub Date : 2025-11-25DOI: 10.1016/j.agrformet.2025.110938
Yutian Lu , Lijuan Miao , Evgenios Agathokleous , Guojie Wang , Dong Wang , Hanyang Jiang , Xiaowei Chuai , Qiang Liu
Vegetation leaf senescence serves as a pivotal biogeochemical process regulating carbon, water, and energy exchanges between terrestrial ecosystems and the atmosphere. Despite considerable research attention on the end of leaf senescence (TLSD), its onset (TLSO) and duration (DLS) remain poorly understood, limiting our ability to predict autumn phenological dynamics. Here, using four phenological extraction methods, we analyzed the trends in TLSO, TLSD, and DLS across temperate China from 2001 to 2023, along with their climatic and physiological drivers. Our results revealed widespread delays in TLSD (0.32 ± 0.13 days/year) and TLSO (0.10 ± 0.16 days/year), leading to a prolonged DLS (0.21 ± 0.17 days/year). Notably, DLS variations were predominantly controlled by shifts in TLSD rather than TLSO, except in water-limited grasslands and cold-adapted deciduous needleleaf forests. Our analysis revealed that TLSD showed stronger climate sensitivity than TLSO, with temperature as the dominant control. Most remarkably, we uncovered a persistent, intrinsic relationship wherein TLSO constrains TLSD, independent of external climatic influences. These results suggest that existing climate-driven phenology models likely underestimate autumn phenological responses by neglecting these intrinsic plant physiological controls. Our study highlights the necessities to integrate both internal regulatory mechanisms (particularly TLSO-TLSD linkages) and external environmental drivers to achieve more accurate predictions of vegetation responses to ongoing climate change.
植被叶片衰老是调节陆地生态系统与大气之间碳、水和能量交换的关键生物地球化学过程。尽管对叶片衰老末期（end of leaf senescence， TLSD）的研究得到了广泛关注，但对其发生时间（TLSO）和持续时间（DLS）的了解仍然很少，这限制了我们预测秋季物候动态的能力。本文采用4种物候提取方法，分析了2001 - 2023年中国温带地区TLSO、TLSD和DLS的变化趋势及其气候和生理驱动因素。我们的研究结果显示，TLSD（0.32±0.13天/年）和TLSO（0.10±0.16天/年）普遍延迟，导致DLS延长（0.21±0.17天/年）。值得注意的是，除限水草地和冷适应落叶针叶林外，DLS的变化主要受TLSD的变化控制，而不是TLSO的变化。结果表明，TLSD的气候敏感性高于TLSO，且温度为主要控制因素。最值得注意的是，我们发现了一种持久的内在关系，其中TLSO约束TLSD，独立于外部气候影响。这些结果表明，现有的气候驱动物候模型可能低估了秋季物候反应，忽略了这些内在的植物生理控制。我们的研究强调了整合内部调节机制（特别是TLSO-TLSD联系）和外部环境驱动因素的必要性，以便更准确地预测植被对持续气候变化的响应。
{"title":"Delayed senescence end prolongs leaf senescence duration in temperate China","authors":"Yutian Lu , Lijuan Miao , Evgenios Agathokleous , Guojie Wang , Dong Wang , Hanyang Jiang , Xiaowei Chuai , Qiang Liu","doi":"10.1016/j.agrformet.2025.110938","DOIUrl":"10.1016/j.agrformet.2025.110938","url":null,"abstract":"<div><div>Vegetation leaf senescence serves as a pivotal biogeochemical process regulating carbon, water, and energy exchanges between terrestrial ecosystems and the atmosphere. Despite considerable research attention on the end of leaf senescence (T<sub>LSD</sub>), its onset (T<sub>LSO</sub>) and duration (D<sub>LS</sub>) remain poorly understood, limiting our ability to predict autumn phenological dynamics. Here, using four phenological extraction methods, we analyzed the trends in T<sub>LSO</sub>, T<sub>LSD</sub>, and D<sub>LS</sub> across temperate China from 2001 to 2023, along with their climatic and physiological drivers. Our results revealed widespread delays in T<sub>LSD</sub> (0.32 ± 0.13 days/year) and T<sub>LSO</sub> (0.10 ± 0.16 days/year), leading to a prolonged D<sub>LS</sub> (0.21 ± 0.17 days/year). Notably, D<sub>LS</sub> variations were predominantly controlled by shifts in T<sub>LSD</sub> rather than T<sub>LSO</sub>, except in water-limited grasslands and cold-adapted deciduous needleleaf forests. Our analysis revealed that T<sub>LSD</sub> showed stronger climate sensitivity than T<sub>LSO</sub>, with temperature as the dominant control. Most remarkably, we uncovered a persistent, intrinsic relationship wherein T<sub>LSO</sub> constrains T<sub>LSD</sub>, independent of external climatic influences. These results suggest that existing climate-driven phenology models likely underestimate autumn phenological responses by neglecting these intrinsic plant physiological controls. Our study highlights the necessities to integrate both internal regulatory mechanisms (particularly T<sub>LSO</sub>-T<sub>LSD</sub> linkages) and external environmental drivers to achieve more accurate predictions of vegetation responses to ongoing climate change.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110938"},"PeriodicalIF":5.7,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598744","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}
Pub Date : 2025-11-25DOI: 10.1016/j.agrformet.2025.110943
Shangqi Xu , Meng Na , Yuqing Miao , Chunjie Tian , Jihai Zhou , Xia Liu
{"title":"Corrigendum to “Responses of methane emissions to global wetland restoration and influencing factors” [Agricultural and Forest Meteorology, 364 (2025), 110459]","authors":"Shangqi Xu , Meng Na , Yuqing Miao , Chunjie Tian , Jihai Zhou , Xia Liu","doi":"10.1016/j.agrformet.2025.110943","DOIUrl":"10.1016/j.agrformet.2025.110943","url":null,"abstract":"","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110943"},"PeriodicalIF":5.7,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145598745","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}
Pub Date : 2025-11-25DOI: 10.1016/j.agrformet.2025.110952
Yi Cen , Lu Hou , Xiaojie Gao , Kai Liu , Yao Li , Yu Shen , Yingpin Yang , Zongbin Wang , Jinnian Wang
Interannual variation of gross primary productivity (GPP), its annual maximum (GPPmax), and growing season length (GSL) are crucial indicators for assessing forest ecosystem responses to climate change. Coarse-resolution satellite observations (e.g., MODIS, 250–500 m) have been widely used to upscale GPP metrics measured by eddy-covariance (EC) flux towers during 2000-present. However, primarily due to data sparsity, studies that use Landsat data to upscale GPP metrics and investigate long-term carbon dynamics are rare, despite its finer resolution (30 m) and extended temporal coverage (1980s-present), which align well with most EC measurements. Here, by using a recently developed Bayesian land surface phenology (BLSP) method that addresses data sparsity of Landsat and a vegetation photosynthesis model (VPM), we explored the potential of Landsat in upscaling long-term GPP metrics. We found that Landsat had comparable performance (R2 = 0.9, RMSE = 1.32 g C m-2d-1, Bias = -0.3 g C m-2d-1) with MODIS (R2 = 0.92, RMSE = 1.13 g C m-2d-1, Bias = -0.22 g C m-2d-1) in estimating GPP validated by EC measurements. Both data sources had higher performance in deciduous (Landsat R2 = 0.89; MODIS R2 = 0.91) than in evergreen forests (Landsat R2 = 0.79; MODIS R2 = 0.88). More importantly, Landsat substantially extended the temporal coverage of GPP, especially prior the MODIS era. This extension enabled a more robust assessment of long-term GPP dynamics, as evidenced by our result that long-term trends of GPP metrics derived from Landsat aligned more closely with EC measurements than those derived from MODIS. Therefore, our study shows that Landsat, coupled with the BLSP model, offers a powerful tool to temporally extend EC-measurements and investigate long-term vegetation ecosystem carbon dynamics.
总初级生产力（GPP）、年最大值（GPPmax）和生长季长度（GSL）的年际变化是评价森林生态系统对气候变化响应的重要指标。2000年至今，粗分辨率卫星观测（例如，MODIS， 250-500米）已被广泛用于提高涡流协方差（EC）通量塔测量的GPP指标。然而，主要由于数据稀疏，使用Landsat数据来提高GPP指标和调查长期碳动态的研究很少，尽管它的分辨率更高（30米），时间覆盖范围更广（1980年代至今），与大多数EC测量结果很好地吻合。在这里，通过使用最近开发的贝叶斯陆地表面物候（BLSP）方法来解决Landsat的数据稀疏性和植被光合作用模型（VPM），我们探索了Landsat在提高长期GPP指标方面的潜力。我们发现Landsat在估计EC测量验证的GPP方面与MODIS （R2 = 0.92, RMSE = 1.13 g C m-2d-1, Bias = -0.22 g C m-2d-1）具有相当的性能（R2 = 0.9, RMSE = 1.32 g C m-2d-1, Bias = -0.3 g C m-2d-1）。两种数据源在落叶林中（Landsat R2 = 0.89, MODIS R2 = 0.91）均优于常绿林中（Landsat R2 = 0.79, MODIS R2 = 0.88）。更重要的是，Landsat极大地扩展了GPP的时间覆盖范围，特别是在MODIS时代之前。这一扩展使我们能够对长期GPP动态进行更稳健的评估，正如我们的结果所证明的那样，从Landsat得出的GPP指标的长期趋势比从MODIS得出的GPP指标更接近EC测量值。因此，我们的研究表明，Landsat与BLSP模型相结合，提供了一个强大的工具来暂时扩展ec测量和研究长期植被生态系统碳动态。
{"title":"Temporally extending long-term forest productivity dynamics using Landsat-derived vegetation index and phenology","authors":"Yi Cen , Lu Hou , Xiaojie Gao , Kai Liu , Yao Li , Yu Shen , Yingpin Yang , Zongbin Wang , Jinnian Wang","doi":"10.1016/j.agrformet.2025.110952","DOIUrl":"10.1016/j.agrformet.2025.110952","url":null,"abstract":"<div><div>Interannual variation of gross primary productivity (GPP), its annual maximum (GPPmax), and growing season length (GSL) are crucial indicators for assessing forest ecosystem responses to climate change. Coarse-resolution satellite observations (e.g., MODIS, 250–500 m) have been widely used to upscale GPP metrics measured by eddy-covariance (EC) flux towers during 2000-present. However, primarily due to data sparsity, studies that use Landsat data to upscale GPP metrics and investigate long-term carbon dynamics are rare, despite its finer resolution (30 m) and extended temporal coverage (1980s-present), which align well with most EC measurements. Here, by using a recently developed Bayesian land surface phenology (BLSP) method that addresses data sparsity of Landsat and a vegetation photosynthesis model (VPM), we explored the potential of Landsat in upscaling long-term GPP metrics. We found that Landsat had comparable performance (R<sup>2</sup> = 0.9, RMSE = 1.32 g C m<sup>-2</sup><span>d</span><sup>-</sup>1, Bias = -0.3 g C m<sup>-2</sup><span>d</span><sup>-1</sup>) with MODIS (R<sup>2</sup> = 0.92, RMSE = 1.13 g C m<sup>-2</sup><span>d</span><sup>-1</sup>, Bias = -0.22 g C m<sup>-2</sup><span>d</span><sup>-1</sup>) in estimating GPP validated by EC measurements. Both data sources had higher performance in deciduous (Landsat R<sup>2</sup> = 0.89; MODIS R<sup>2</sup> = 0.91) than in evergreen forests (Landsat R<sup>2</sup> = 0.79; MODIS R<sup>2</sup> = 0.88). More importantly, Landsat substantially extended the temporal coverage of GPP, especially prior the MODIS era. This extension enabled a more robust assessment of long-term GPP dynamics, as evidenced by our result that long-term trends of GPP metrics derived from Landsat aligned more closely with EC measurements than those derived from MODIS. Therefore, our study shows that Landsat, coupled with the BLSP model, offers a powerful tool to temporally extend EC-measurements and investigate long-term vegetation ecosystem carbon dynamics.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"377 ","pages":"Article 110952"},"PeriodicalIF":5.7,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145593694","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}
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