Pub Date : 2024-10-24DOI: 10.1016/j.foreco.2024.122339
Yanik.Y. Akin , Romain L. Glèlè Kakaï , Orou G. Gaoue
Understanding intraspecific demographic trade-offs is fundamental for capturing plant responses to global changes such as disturbance and climate variability. The coordinated resource allocation hypothesis suggests that plants invest in demographic processes (such as survival, growth, or fecundity) relative to resource availability and environmental challenges. Most studies have primarily focused on the effects of disturbance or climate regions on species demographic processes separately, with limited attention given to the associated trade-offs. However, it is crucial to understand the synergistic effects of climate variation and disturbance on these processes to accurately forecast forest species dynamics. Three series of data were collected from 12 populations of African mesquite trees, Prosopis africana, distributed across three contrasting ecological regions in Benin, West Africa. Within a permanent plot, individuals of P. africana were tagged with numbered aluminum tags, and data were collected on the demography parameters of each individual. We found demographic trade-offs between survival and growth, growth and fecundity but not between survival and fecundity. The patterns of trade-offs mainly varied across synergistic effects of climate zone and disturbance. These findings highlight the strategies plants may employed under disturbance and climate variations in tropical forests and emphasize their significance in ecology and forest management.
{"title":"Chronic anthropogenic disturbance and climate synergistically shape demographic trade-offs in a tropical fuelwood tree","authors":"Yanik.Y. Akin , Romain L. Glèlè Kakaï , Orou G. Gaoue","doi":"10.1016/j.foreco.2024.122339","DOIUrl":"10.1016/j.foreco.2024.122339","url":null,"abstract":"<div><div>Understanding intraspecific demographic trade-offs is fundamental for capturing plant responses to global changes such as disturbance and climate variability. The coordinated resource allocation hypothesis suggests that plants invest in demographic processes (such as survival, growth, or fecundity) relative to resource availability and environmental challenges. Most studies have primarily focused on the effects of disturbance or climate regions on species demographic processes separately, with limited attention given to the associated trade-offs. However, it is crucial to understand the synergistic effects of climate variation and disturbance on these processes to accurately forecast forest species dynamics. Three series of data were collected from 12 populations of African mesquite trees, <em>Prosopis africana</em>, distributed across three contrasting ecological regions in Benin, West Africa. Within a permanent plot, individuals of <em>P. africana</em> were tagged with numbered aluminum tags, and data were collected on the demography parameters of each individual. We found demographic trade-offs between survival and growth, growth and fecundity but not between survival and fecundity. The patterns of trade-offs mainly varied across synergistic effects of climate zone and disturbance. These findings highlight the strategies plants may employed under disturbance and climate variations in tropical forests and emphasize their significance in ecology and forest management.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"573 ","pages":"Article 122339"},"PeriodicalIF":3.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532559","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}
Pub Date : 2024-10-23DOI: 10.1016/j.foreco.2024.122331
Carl A. Norlen , Kyle S. Hemes , Jonathan A. Wang , James T. Randerson , John J. Battles , Carmen L. Tubbesing , Michael L. Goulden
Climate change is amplifying both wildfire burned area and severity, as well as incidents of drought-induced tree mortality (dieback). Direct effects from climate change amplify wildfires and episodes of drought-induced dieback have well-known impacts on forest’s ability to regulate climate, provide water, and store carbon. Less understood are how past disturbances produce interaction effects that can change subsequent disturbance occurrence and intensity, with implications for management decisions that can promote forest resistance and resilience. We constructed two parallel forest chrono-sequences by combining a geospatial database of historical fire with satellite and airborne observations of forests in the Sierra Nevada of California to assess the impact of fire history on vegetation recovery, water use (evapotranspiration), and drought-induced forest dieback. We used these data sets to assess two research questions: (1.) Does fire history amplify or reduce drought-dieback intensity? (2.) What mechanisms explain how fire-induced changes to forest structure and ET alter subsequent forest dieback intensity? We show that recent fire history decreased drought-induced forest dieback intensity, compared to unburned controls. These fire-affected forests were characterized by reduced tree cover and decreased evapotranspiration, which combined to increase drought resistance more than would be expected by either effect individually. Two decades post-fire, evapotranspiration returned to pre-fire conditions. Tree and shrub cover started to approach pre-fire conditions, except for high severity fires where decreased tree cover and increased shrub cover persisted. Field based research on fuels treatments suggests that fire history may also increase longer term forest resilience. In fire-prone conifer forests, interaction effects from recent low and moderate severity fires will increase drought resistance and perhaps longer-term forest stability.
{"title":"Recent fire history enhances semi-arid conifer forest drought resistance","authors":"Carl A. Norlen , Kyle S. Hemes , Jonathan A. Wang , James T. Randerson , John J. Battles , Carmen L. Tubbesing , Michael L. Goulden","doi":"10.1016/j.foreco.2024.122331","DOIUrl":"10.1016/j.foreco.2024.122331","url":null,"abstract":"<div><div>Climate change is amplifying both wildfire burned area and severity, as well as incidents of drought-induced tree mortality (dieback). Direct effects from climate change amplify wildfires and episodes of drought-induced dieback have well-known impacts on forest’s ability to regulate climate, provide water, and store carbon. Less understood are how past disturbances produce interaction effects that can change subsequent disturbance occurrence and intensity, with implications for management decisions that can promote forest resistance and resilience. We constructed two parallel forest chrono-sequences by combining a geospatial database of historical fire with satellite and airborne observations of forests in the Sierra Nevada of California to assess the impact of fire history on vegetation recovery, water use (evapotranspiration), and drought-induced forest dieback. We used these data sets to assess two research questions: (1.) Does fire history amplify or reduce drought-dieback intensity? (2.) What mechanisms explain how fire-induced changes to forest structure and ET alter subsequent forest dieback intensity? We show that recent fire history decreased drought-induced forest dieback intensity, compared to unburned controls. These fire-affected forests were characterized by reduced tree cover and decreased evapotranspiration, which combined to increase drought resistance more than would be expected by either effect individually. Two decades post-fire, evapotranspiration returned to pre-fire conditions. Tree and shrub cover started to approach pre-fire conditions, except for high severity fires where decreased tree cover and increased shrub cover persisted. Field based research on fuels treatments suggests that fire history may also increase longer term forest resilience. In fire-prone conifer forests, interaction effects from recent low and moderate severity fires will increase drought resistance and perhaps longer-term forest stability.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"573 ","pages":"Article 122331"},"PeriodicalIF":3.7,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532557","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}
Pub Date : 2024-10-23DOI: 10.1016/j.foreco.2024.122344
Esther Peña-Molina , Daniel Moya , Agustín Merino , Álvaro Fajardo-Cantos , Asunción Díaz-Montero , Fuensanta García-Orenes , Manuel Esteban Lucas-Borja , Jorge de las Heras
Postfire management actions are used to mitigate damage caused by wildfires. Salvage logging, often employed to restore ecosystem functions in burnt stands, plays an essential role in reducing economic losses and the burn severity of future wildfires. However, its ecological implications for soil functionality still need to be understood, especially in the Mediterranean basin, which is prone to erosion and desertification. This study aimed to investigate the effects of fire on (i) soil organic matter (SOM) quality and composition using differential scanning calorimetry-thermogravimetry (DSC-TG) and solid-state nuclear magnetic resonance (13C CPMAS NMR) and (ii) phosphorus (P) forms using solid-state 31P NMR spectroscopy in a wildfire that affected 3200 ha in southeastern Spain in July 2017. One year after the fire, we monitored four Pinus halepensis Mill. stand categories based on soil burn severity (SBS): unburnt, low SBS, high SBS and high SBS areas with salvage logging (n=36, nine plots per SBS level). We collected soil samples and analysed soil pH, SOM content and SOM quality, along with biological activity indicators (carbon biomass, basal respiration, β-glucosidase, phosphatase activities) and P forms. We ran ANOVA statistical tests to identify significant differences in soil properties among SBS levels. We also established general linear regressions of thermo-recalcitrance values and aromaticity with biological soil quality indices to compare both techniques for detecting changes in SOM quality and composition. The results indicated that fire increased soil pH (up to 0.3), particularly in the plots with higher SBS levels. SOM decreased significantly with increasing SBS level (down to < 5 % at the high SBS level), with a shift from labile compounds (carbohydrates) to more recalcitrant ones (aromatics). Organic P forms were depleted, while orthophosphate levels rose, increasing the risk of irreversible fixation. This study also highlights that DSC-TG is a cost-effective technique for assessing SOM quality changes. Understanding these effects is essential for developing policies to conserve and restore fire-affected areas and to promote practices that enhance soil functionality and resilience.
火后管理行动用于减轻野火造成的损失。抢救性砍伐通常用于恢复烧毁林分的生态系统功能，在减少经济损失和未来野火的烧毁严重程度方面发挥着至关重要的作用。然而，人们仍需了解其对土壤功能的生态影响，尤其是在易受侵蚀和荒漠化影响的地中海盆地。本研究旨在利用差示扫描量热法（DSC-TG）和固态核磁共振（13C CPMAS NMR）研究火灾对(i) 土壤有机质（SOM）质量和组成的影响，以及(ii) 利用固态 31P NMR 光谱研究火灾对磷（P）形式的影响。火灾发生一年后，我们根据土壤焚烧严重程度（SBS）对四类 Pinus halepensis Mill.林分进行了监测：未焚烧区、低 SBS 区、高 SBS 区和高 SBS 区的抢救性采伐区（n=36，每个 SBS 等级九个地块）。我们采集了土壤样本，分析了土壤 pH 值、SOM 含量和 SOM 质量，以及生物活性指标（碳生物量、基础呼吸、β-葡萄糖苷酶、磷酸酶活性）和 P 形态。我们进行了方差分析统计检验，以确定不同 SBS 水平下土壤特性的显著差异。我们还建立了热重现性值和芳香度与生物土壤质量指数的一般线性回归，以比较这两种检测 SOM 质量和组成变化的技术。结果表明，火灾提高了土壤 pH 值（最高达 0.3），特别是在 SBS 水平较高的地块。随着 SBS 水平的增加，SOM 明显减少（SBS 水平高时减少至 5%），从易腐烂化合物（碳水化合物）转向更难分解的化合物（芳香族化合物）。有机态磷被耗尽，而正磷酸盐水平上升，增加了不可逆固定的风险。这项研究还表明，DSC-TG 是评估 SOM 质量变化的一种经济有效的技术。了解这些影响对于制定受火灾影响地区的保护和恢复政策以及推广提高土壤功能和恢复能力的方法至关重要。
{"title":"Fire and salvage logging increased recalcitrant soil organic matter and reduced soil functionality in Mediterranean pine forests.","authors":"Esther Peña-Molina , Daniel Moya , Agustín Merino , Álvaro Fajardo-Cantos , Asunción Díaz-Montero , Fuensanta García-Orenes , Manuel Esteban Lucas-Borja , Jorge de las Heras","doi":"10.1016/j.foreco.2024.122344","DOIUrl":"10.1016/j.foreco.2024.122344","url":null,"abstract":"<div><div>Postfire management actions are used to mitigate damage caused by wildfires. Salvage logging, often employed to restore ecosystem functions in burnt stands, plays an essential role in reducing economic losses and the burn severity of future wildfires. However, its ecological implications for soil functionality still need to be understood, especially in the Mediterranean basin, which is prone to erosion and desertification. This study aimed to investigate the effects of fire on (i) soil organic matter (SOM) quality and composition using differential scanning calorimetry-thermogravimetry (DSC-TG) and solid-state nuclear magnetic resonance (<sup>13</sup>C CPMAS NMR) and (ii) phosphorus (P) forms using solid-state <sup>31</sup>P NMR spectroscopy in a wildfire that affected 3200 ha in southeastern Spain in July 2017. One year after the fire, we monitored four <em>Pinus halepensis</em> Mill. stand categories based on soil burn severity (SBS): unburnt, low SBS, high SBS and high SBS areas with salvage logging (n=36, nine plots per SBS level). We collected soil samples and analysed soil pH, SOM content and SOM quality, along with biological activity indicators (carbon biomass, basal respiration, β-glucosidase, phosphatase activities) and P forms. We ran ANOVA statistical tests to identify significant differences in soil properties among SBS levels. We also established general linear regressions of thermo-recalcitrance values and aromaticity with biological soil quality indices to compare both techniques for detecting changes in SOM quality and composition. The results indicated that fire increased soil pH (up to 0.3), particularly in the plots with higher SBS levels. SOM decreased significantly with increasing SBS level (down to < 5 % at the high SBS level), with a shift from labile compounds (carbohydrates) to more recalcitrant ones (aromatics). Organic P forms were depleted, while orthophosphate levels rose, increasing the risk of irreversible fixation. This study also highlights that DSC-TG is a cost-effective technique for assessing SOM quality changes. Understanding these effects is essential for developing policies to conserve and restore fire-affected areas and to promote practices that enhance soil functionality and resilience.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"573 ","pages":"Article 122344"},"PeriodicalIF":3.7,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532922","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}
Pub Date : 2024-10-22DOI: 10.1016/j.foreco.2024.122338
Yi Wu , Dongyan Zhao , Yuhan Wang , Jipeng Wang , Yuying Wu , Peihao Peng , Liyuan Yang , Yanhong Wu , Haijian Bing , Roland Bol
Global wildfires occurring with ever escalating frequency and intensity profoundly disrupt soil phosphorus (P) cycling in forest ecosystems. The impact of plant species on post-fire soil P transformation, particularly in alpine forests, remains largely unexplored. This study addressed this gap by investigating both bulk soils (BS) and root-zone soils (RS) across three plant species (shrub: Sophora davidii and Quercus aquifolioides, tree: Pinus densata) in the alpine forest of the eastern Tibetan Plateau, three years after a wildfire event. We examined variations in soil P fractions under varying wildfire intensities using the modified Hedley sequential extraction method. Compared to unburned soils, the burned soils exhibited significantly reduced organic P (Po) but increased inorganic P (Pi) concentrations in BS. However, both Pi and Po concentrations decreased in the burned RS, particularly for S. davidii and P. densata, indicating the effects of biological P utilization. The increased specific phosphatase activity and the ratio of carbon to Po suggested increased P limitation in the post-fire environment. Notably, the N2-fixer S. davidii primarily reduced labile P fractions through direct plant P uptake, while conifer tree species P. densata tended to deplete all extractable P fractions, probably through diverse P utilization strategies. Conversely, Q. aquifolioides did not significantly alter soil P fractions, likely due to its fire-resistant properties. These species-dependent impacts on post-fire P fractions were further corroborated by their distinct influences on soil and microbial traits. Our findings underscore the critical roles of functional-specific plant species in post-fire soil P dynamics in alpine forests, with conifer trees exhibiting the best P mining and utilization capacity.
全球野火发生的频率和强度不断增加，严重破坏了森林生态系统的土壤磷循环。植物物种对火灾后土壤磷转化的影响，尤其是在高山森林中，在很大程度上仍未得到探索。本研究针对这一空白，在青藏高原东部的高山森林中，在野火发生三年后，调查了三种植物（灌木：Sophora davidii 和 Quercus aquifolioides，乔木：Pinus densata）的块状土壤（BS）和根域土壤（RS）。我们采用改良的赫德利序列提取法研究了不同野火强度下土壤中钾组分的变化。与未烧毁的土壤相比，烧毁土壤中的有机钾（Po）含量明显减少，但无机钾（Pi）含量增加。然而，在烧毁的 RS 中，Pi 和 Po 的浓度都有所下降，尤其是 S. davidii 和 P. densata，这表明生物对 P 的利用产生了影响。特异性磷酸酶活性和碳-钾比率的增加表明，火灾后环境中的钾限制增加了。值得注意的是，固氮植物 S. davidii 主要是通过直接吸收植物所需的 P 来减少可溶性 P 部分，而针叶树种 P. densata 则倾向于消耗所有可提取的 P 部分，这可能是通过不同的 P 利用策略实现的。相反，Q. aquifolioides 并未显著改变土壤中的钾组分，这可能是由于它具有耐火特性。物种对土壤和微生物特征的不同影响进一步证实了这些物种对火灾后 P 分馏的影响。我们的研究结果表明，功能性植物物种在高山森林火后土壤磷动态中起着关键作用，针叶树表现出最佳的磷挖掘和利用能力。
{"title":"Plant species modulate wildfire effects on soil phosphorus fractions in alpine forest of Eastern Tibetan Plateau","authors":"Yi Wu , Dongyan Zhao , Yuhan Wang , Jipeng Wang , Yuying Wu , Peihao Peng , Liyuan Yang , Yanhong Wu , Haijian Bing , Roland Bol","doi":"10.1016/j.foreco.2024.122338","DOIUrl":"10.1016/j.foreco.2024.122338","url":null,"abstract":"<div><div>Global wildfires occurring with ever escalating frequency and intensity profoundly disrupt soil phosphorus (P) cycling in forest ecosystems. The impact of plant species on post-fire soil P transformation, particularly in alpine forests, remains largely unexplored. This study addressed this gap by investigating both bulk soils (BS) and root-zone soils (RS) across three plant species (shrub: <em>Sophora davidii</em> and <em>Quercus aquifolioides</em>, tree: <em>Pinus densata</em>) in the alpine forest of the eastern Tibetan Plateau, three years after a wildfire event. We examined variations in soil P fractions under varying wildfire intensities using the modified Hedley sequential extraction method. Compared to unburned soils, the burned soils exhibited significantly reduced organic P (P<sub>o</sub>) but increased inorganic P (P<sub>i</sub>) concentrations in BS. However, both P<sub>i</sub> and P<sub>o</sub> concentrations decreased in the burned RS, particularly for <em>S. davidii</em> and <em>P. densata</em>, indicating the effects of biological P utilization. The increased specific phosphatase activity and the ratio of carbon to P<sub>o</sub> suggested increased P limitation in the post-fire environment. Notably, the N<sub>2</sub>-fixer <em>S. davidii</em> primarily reduced labile P fractions through direct plant P uptake, while conifer tree species <em>P. densata</em> tended to deplete all extractable P fractions, probably through diverse P utilization strategies. Conversely, <em>Q. aquifolioides</em> did not significantly alter soil P fractions, likely due to its fire-resistant properties. These species-dependent impacts on post-fire P fractions were further corroborated by their distinct influences on soil and microbial traits. Our findings underscore the critical roles of functional-specific plant species in post-fire soil P dynamics in alpine forests, with conifer trees exhibiting the best P mining and utilization capacity.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"573 ","pages":"Article 122338"},"PeriodicalIF":3.7,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532558","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}
Pub Date : 2024-10-20DOI: 10.1016/j.foreco.2024.122336
Decheng Xiong , Jinxue Huang , Xulong Du , Teng-chiu Lin , Yuanhao Liu , Shidong Chen , Xiaofei Liu , Chao Xu , Zhijie Yang , Yusheng Yang
Subtropical China is projected to experience elevated temperature greater than the mean global temperature increase and is accompanied by reduced precipitation. The plasticity of roots to changing environment strongly influences ecosystem feedbacks to climate change. However, knowledge gaps on the individual and combined effects of warming and precipitation reduction on root systems hinder our ability to accurately predict the growth and adaptability of forests under future climate change. To examine the effects of warming (W) and precipitation reduction (P) on roots physiology and morphology of Chinese-fir saplings, we used a randomized complete block design with factorial soil warming (ambient, ambient + 5℃) and precipitation reduction (ambient, ambient-50 %) treatments. A full excavation method was adopted to obtain roots, then we measured the root physiology (osmoregulatory substances, oxidant substances, protective enzymes, endogenous hormones), morphology (specific root length, SRL; surface root area, SRA; root tissue density, RTD). The content of carbon and nitrogen, isotopes (δ13C and δ15N); soil temperature, soil moisture and sapling growth were also measured. We found that compared with the control, W decreased the abscisic acid (IAA) content; P increased the contents of hydrogen peroxide (H2O2) and proline (Pro), and decreased the contents of IAA and cytokinin (CTK); warming plus precipitation reduction (WP) increased the Pro content, and decreased the contents of IAA and CTK. In addition, the effects of W and P on root morphology varied with soil depth and root diameter class. W, P, and WP all increased fine root SRL and SRA in deep soil. Warming and precipitation reduction could affect physiological traits (e.g. non-enzymatic substances and antioxidant enzymes) and subsequently morphological traits via influencing soil environment and root tissue chemistry. Collectively, the results indicated that Chinese-fir saplings responded to warming and precipitation reduction by comprehensive regulation of the non-enzymatic substances (e.g., osmotic substances and endogenous hormones) of fine roots and changing root morphological characteristics in deep soil.
预计中国亚热带地区的气温升幅将超过全球平均气温升幅，同时降水量也将减少。根系对环境变化的可塑性极大地影响了生态系统对气候变化的反馈。然而，关于气候变暖和降水减少对根系的单独影响和综合影响的知识空白，阻碍了我们准确预测未来气候变化下森林生长和适应性的能力。为了研究气候变暖（W）和降水减少（P）对中冷杉树苗根系生理和形态的影响，我们采用了随机完全区组设计，对土壤增温（常温、常温+5℃）和降水减少（常温、常温-50%）进行了因子处理。采用完全挖掘法获得根系，然后测量根系生理（渗透调节物质、氧化物质、保护酶、内源激素）、形态（比根长 SRL；比表面根面积 SRA；根组织密度 RTD）。此外，还测量了碳和氮的含量、同位素（δ13C 和 δ15N）、土壤温度、土壤湿度和树苗生长情况。我们发现，与对照相比，加温降低了脱落酸（IAA）的含量；加压增加了过氧化氢（H2O2）和脯氨酸（Pro）的含量，降低了IAA和细胞分裂素（CTK）的含量；加温加降水（WP）增加了Pro的含量，降低了IAA和CTK的含量。此外，W 和 P 对根系形态的影响随土壤深度和根直径等级的不同而不同。W、P和WP都增加了深层土壤中细根的SRL和SRA。气候变暖和降水减少可能会通过影响土壤环境和根组织化学来影响生理性状（如非酶物质和抗氧化酶），进而影响形态性状。总之，研究结果表明，冷杉树苗通过综合调节细根的非酶物质（如渗透物质和内源激素）和改变深层土壤中的根系形态特征来应对气候变暖和降水减少。
{"title":"Root physiological and morphology processes co-regulate the growth of Chinese-fir saplings in response to warming and precipitation reduction in the sub-tropical regions","authors":"Decheng Xiong , Jinxue Huang , Xulong Du , Teng-chiu Lin , Yuanhao Liu , Shidong Chen , Xiaofei Liu , Chao Xu , Zhijie Yang , Yusheng Yang","doi":"10.1016/j.foreco.2024.122336","DOIUrl":"10.1016/j.foreco.2024.122336","url":null,"abstract":"<div><div>Subtropical China is projected to experience elevated temperature greater than the mean global temperature increase and is accompanied by reduced precipitation. The plasticity of roots to changing environment strongly influences ecosystem feedbacks to climate change. However, knowledge gaps on the individual and combined effects of warming and precipitation reduction on root systems hinder our ability to accurately predict the growth and adaptability of forests under future climate change. To examine the effects of warming (W) and precipitation reduction (P) on roots physiology and morphology of Chinese-fir saplings, we used a randomized complete block design with factorial soil warming (ambient, ambient + 5℃) and precipitation reduction (ambient, ambient-50 %) treatments. A full excavation method was adopted to obtain roots, then we measured the root physiology (osmoregulatory substances, oxidant substances, protective enzymes, endogenous hormones), morphology (specific root length, SRL; surface root area, SRA; root tissue density, RTD). The content of carbon and nitrogen, isotopes (δ<sup>13</sup>C and δ<sup>15</sup>N); soil temperature, soil moisture and sapling growth were also measured. We found that compared with the control, W decreased the abscisic acid (IAA) content; P increased the contents of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and proline (Pro), and decreased the contents of IAA and cytokinin (CTK); warming plus precipitation reduction (WP) increased the Pro content, and decreased the contents of IAA and CTK. In addition, the effects of W and P on root morphology varied with soil depth and root diameter class. W, P, and WP all increased fine root SRL and SRA in deep soil. Warming and precipitation reduction could affect physiological traits (e.g. non-enzymatic substances and antioxidant enzymes) and subsequently morphological traits via influencing soil environment and root tissue chemistry. Collectively, the results indicated that Chinese-fir saplings responded to warming and precipitation reduction by comprehensive regulation of the non-enzymatic substances (e.g., osmotic substances and endogenous hormones) of fine roots and changing root morphological characteristics in deep soil.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"572 ","pages":"Article 122336"},"PeriodicalIF":3.7,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533112","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}
Pub Date : 2024-10-19DOI: 10.1016/j.foreco.2024.122340
Thomas S. Ovenden , Richard L. Jinks , William L. Mason , Gary Kerr , Chris Reynolds
Globally, climate change is altering both seasonal climates and the occurrence of extreme climate events, resulting in a drive to ensure our forests are resilient to these changes and the challenges they will bring. In Great Britain (GB), there has been a reliance on a limited number of species grown in monospecific plantations and concerns over the resilience of these forests is leading to a growing recognition of the need to diversify tree species composition. However, evidence of the relative growth rate and survival of alternative tree species and provenances during the critical establishment phase (typically within five or six years of planting) is often limited, hampering consideration of the wider adoption of many potentially suitable species. To address this knowledge gap, we compared tree height and survival data six years after planting from 34 provenances across 18 tree species at five experimental sites established across GB in 2012 in monospecific plots. For coniferous species, we found that Larix decidua, Larix x marschlinsii and Pinus radiata (on drier sites) were consistently amongst the tallest species, but survival could be variable. Pseudotsuga menziesii and Pinus pinaster also showed good early growth, matching the growth rate of Picea sitchensis (the most widely planted conifer in GB) when co-occurring and often exhibited good survival. In contrast Picea orientalis was slow to establish and amongst the smallest species at all five sites after six years, with Cedrus atlantica also performing poorly where planted. Surprisingly, we found very few differences in both mean tree height and survival between most provenances of the same species across all experimental sites, though more obvious differences may emerge as these trees mature. Only a small number of broadleaf species were available for analysis at age six in this study, but as expected Betula pendula generally performed well, while Acer macrophyllum often had very high mortality. While there are concerns around the susceptibility of pine species to Dothistroma septosporum and the future use of larch species in GB forestry is currently limited by the disease Phytophthora ramorum, our results highlight the potential for these species to establish well and exhibit good initial growth and survival on drier sites, with the same true of P. menziesii on moister sites. Future work should aim to understand whether further differences between species and provenances emerge with age and explore the potential of these emerging species as components of mixed-species stands to increase GB forest resilience to climate change.
{"title":"A comparison of the early growth and survival of lesser-known tree species for climate change adaptation in Britain","authors":"Thomas S. Ovenden , Richard L. Jinks , William L. Mason , Gary Kerr , Chris Reynolds","doi":"10.1016/j.foreco.2024.122340","DOIUrl":"10.1016/j.foreco.2024.122340","url":null,"abstract":"<div><div>Globally, climate change is altering both seasonal climates and the occurrence of extreme climate events, resulting in a drive to ensure our forests are resilient to these changes and the challenges they will bring. In Great Britain (GB), there has been a reliance on a limited number of species grown in monospecific plantations and concerns over the resilience of these forests is leading to a growing recognition of the need to diversify tree species composition. However, evidence of the relative growth rate and survival of alternative tree species and provenances during the critical establishment phase (typically within five or six years of planting) is often limited, hampering consideration of the wider adoption of many potentially suitable species. To address this knowledge gap, we compared tree height and survival data six years after planting from 34 provenances across 18 tree species at five experimental sites established across GB in 2012 in monospecific plots. For coniferous species, we found that <em>Larix decidua</em>, <em>Larix</em> x <em>marschlinsii</em> and <em>Pinus radiata</em> (on drier sites) were consistently amongst the tallest species, but survival could be variable. <em>Pseudotsuga menziesii</em> and <em>Pinus pinaster</em> also showed good early growth, matching the growth rate of <em>Picea sitchensis</em> (the most widely planted conifer in GB) when co-occurring and often exhibited good survival. In contrast <em>Picea orientalis</em> was slow to establish and amongst the smallest species at all five sites after six years, with <em>Cedrus atlantica</em> also performing poorly where planted. Surprisingly, we found very few differences in both mean tree height and survival between most provenances of the same species across all experimental sites, though more obvious differences may emerge as these trees mature. Only a small number of broadleaf species were available for analysis at age six in this study, but as expected <em>Betula pendula</em> generally performed well, while <em>Acer macrophyllum</em> often had very high mortality. While there are concerns around the susceptibility of pine species to <em>Dothistroma septosporum</em> and the future use of larch species in GB forestry is currently limited by the disease <em>Phytophthora ramorum</em>, our results highlight the potential for these species to establish well and exhibit good initial growth and survival on drier sites, with the same true of <em>P. menziesii</em> on moister sites. Future work should aim to understand whether further differences between species and provenances emerge with age and explore the potential of these emerging species as components of mixed-species stands to increase GB forest resilience to climate change.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"572 ","pages":"Article 122340"},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532551","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}
Pub Date : 2024-10-19DOI: 10.1016/j.foreco.2024.122333
Jarosław Skłodowski , Maria Sterzyńska
There are a number of ways to clear the aftermath of a windthrow disturbance of forest stands, the most common practice being to remove all broken trees and broken-off crowns lying on the ground. This practice leads to complete exposure of the soil, which deprives soil invertebrates (including Collembola) of the protection of trees that affords them a chance of surviving. Accordingly, following a windthrow disturbance of pine stands in 2017, a three-year study of collembolan assemblages was undertaken in stands spared from salvage logging. We aimed to test the effect of three different levels of disturbance (severely, moderately and least disturbed stands with a canopy cover of 0–20 %, 20–60 % and 60–90 %, respectively) on the survival of Collembola assemblages and to determine its association with changes in the soil environment and in the LAI index. Additionally, in the severely and moderately disturbed stands, Collembola were sampled between crowns of fallen trees and under the crowns. There were no significant differences in density, species richness and proportions of individuals of belowground “soil” and aboveground “epedaphic” species between the Collembolan assemblages that were associated with the degree of windthrow disturbance and time since disturbance. The study confirmed the presence of a significantly higher number of species and proportion of “epedaphic” species, and a lower proportion of “soil” species in the assemblages sampled under fallen tree crowns than between crowns. Analysis of principal response curves (PRC) yielded unexpected results as it indicated that these differences were significant only in the first year post-disturbance, thus suggesting a very short-lasting protective effect of tree crowns on Collembola, RDA analysis with preselected factors from environmental variables of interest (LAI of standing and fallen tree crowns, soil respiration, soil temperature and humidity, soil pH and soil nitrogen and carbon content) indicated the LAI index as significant for the Collembolan assemblages in the first yearpost-disturbance, soil moisture in the second year, and soil temperature in the third year. This sequence of significant indices over a three year period is compatible with the fallen crowns becoming more and more thinned as a result of needles falling off (from shade to full exposure to sunlight). We nevertheless postulate that at least some trees or their crowns lying on the ground should be left in place during clearance of windthrow-affected tree stands to facilitate restoration of the soil biota.
{"title":"Tree crowns broken off by windstorms are an unstable life raft for Collembola","authors":"Jarosław Skłodowski , Maria Sterzyńska","doi":"10.1016/j.foreco.2024.122333","DOIUrl":"10.1016/j.foreco.2024.122333","url":null,"abstract":"<div><div>There are a number of ways to clear the aftermath of a windthrow disturbance of forest stands, the most common practice being to remove all broken trees and broken-off crowns lying on the ground. This practice leads to complete exposure of the soil, which deprives soil invertebrates (including Collembola) of the protection of trees that affords them a chance of surviving. Accordingly, following a windthrow disturbance of pine stands in 2017, a three-year study of collembolan assemblages was undertaken in stands spared from salvage logging. We aimed to test the effect of three different levels of disturbance (severely, moderately and least disturbed stands with a canopy cover of 0–20 %, 20–60 % and 60–90 %, respectively) on the survival of Collembola assemblages and to determine its association with changes in the soil environment and in the LAI index. Additionally, in the severely and moderately disturbed stands, Collembola were sampled between crowns of fallen trees and under the crowns. There were no significant differences in density, species richness and proportions of individuals of belowground “soil” and aboveground “epedaphic” species between the Collembolan assemblages that were associated with the degree of windthrow disturbance and time since disturbance. The study confirmed the presence of a significantly higher number of species and proportion of “epedaphic” species, and a lower proportion of “soil” species in the assemblages sampled under fallen tree crowns than between crowns. Analysis of principal response curves (PRC) yielded unexpected results as it indicated that these differences were significant only in the first year post-disturbance, thus suggesting a very short-lasting protective effect of tree crowns on Collembola, RDA analysis with preselected factors from environmental variables of interest (LAI of standing and fallen tree crowns, soil respiration, soil temperature and humidity, soil pH and soil nitrogen and carbon content) indicated the LAI index as significant for the Collembolan assemblages in the first yearpost-disturbance, soil moisture in the second year, and soil temperature in the third year. This sequence of significant indices over a three year period is compatible with the fallen crowns becoming more and more thinned as a result of needles falling off (from shade to full exposure to sunlight). We nevertheless postulate that at least some trees or their crowns lying on the ground should be left in place during clearance of windthrow-affected tree stands to facilitate restoration of the soil biota.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"572 ","pages":"Article 122333"},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533111","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}
Pub Date : 2024-10-19DOI: 10.1016/j.foreco.2024.122326
Michael T. Stoddard , Kyle C. Rodman , Connor D. Crouch , David W. Huffman , Peter Z. Fulé , Kristen M. Waring , Margaret M. Moore
Changes in forest structure and shifts in tree species composition have occurred globally due to climate change and altered disturbance regimes. With climate trending toward warmer and drier conditions, these altered forest communities may reorganize in diverse and unpredictable ways. This is especially true in mountain environments where a range of vegetation types and abiotic conditions coexist. In this study, we used long-term permanent plot data from a site spanning broad environmental gradients to assess regeneration and mortality patterns in populations of aspen (Populus tremuloides). The study site, located on the San Francisco Peaks, Arizona, USA, is near the hot, dry edge of the species’ range and has experienced compounding pressure from extreme drought, chronic ungulate browsing, and wildfire in the past two decades. Over a 20-year study period, spanning one of the most prolonged drought periods in at least 1200 years, aspen overstory mortality averaged 42 % and was most common in smaller, younger trees and at lower elevations. Aspen regeneration density increased 13 % and was found in a greater proportion of study sites. However, we observed a noticeable lack of stems in the tallest regeneration size class (>200 cm) and the smaller tree size class (2.5–15 cm in diameter), potentially indicating a demographic bottleneck whereby few trees are recruiting into the overstory. Likewise, prolific aspen suckering occurred after a 2001 wildfire, although regeneration density eventually decreased to pre-fire levels, with <1 % of individuals reaching heights >200 cm. Aspen regeneration densities showed the greatest increases in cool, wet sites and beneath open forest canopies. Disturbances function as catalysts for aspen regeneration, but persistence of aspen stands depends on recruitment of stems into overstory size classes, a process that is limited, particularly on lower and more exposed sites.
{"title":"Multi-decadal aspen dynamics show recruitment bottleneck across complex mountain community","authors":"Michael T. Stoddard , Kyle C. Rodman , Connor D. Crouch , David W. Huffman , Peter Z. Fulé , Kristen M. Waring , Margaret M. Moore","doi":"10.1016/j.foreco.2024.122326","DOIUrl":"10.1016/j.foreco.2024.122326","url":null,"abstract":"<div><div>Changes in forest structure and shifts in tree species composition have occurred globally due to climate change and altered disturbance regimes. With climate trending toward warmer and drier conditions, these altered forest communities may reorganize in diverse and unpredictable ways. This is especially true in mountain environments where a range of vegetation types and abiotic conditions coexist. In this study, we used long-term permanent plot data from a site spanning broad environmental gradients to assess regeneration and mortality patterns in populations of aspen (<em>Populus tremuloides</em>). The study site, located on the San Francisco Peaks, Arizona, USA, is near the hot, dry edge of the species’ range and has experienced compounding pressure from extreme drought, chronic ungulate browsing, and wildfire in the past two decades. Over a 20-year study period, spanning one of the most prolonged drought periods in at least 1200 years, aspen overstory mortality averaged 42 % and was most common in smaller, younger trees and at lower elevations. Aspen regeneration density increased 13 % and was found in a greater proportion of study sites. However, we observed a noticeable lack of stems in the tallest regeneration size class (>200 cm) and the smaller tree size class (2.5–15 cm in diameter), potentially indicating a demographic bottleneck whereby few trees are recruiting into the overstory. Likewise, prolific aspen suckering occurred after a 2001 wildfire, although regeneration density eventually decreased to pre-fire levels, with <1 % of individuals reaching heights >200 cm. Aspen regeneration densities showed the greatest increases in cool, wet sites and beneath open forest canopies. Disturbances function as catalysts for aspen regeneration, but persistence of aspen stands depends on recruitment of stems into overstory size classes, a process that is limited, particularly on lower and more exposed sites.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"572 ","pages":"Article 122326"},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532542","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}
Pub Date : 2024-10-19DOI: 10.1016/j.foreco.2024.122330
Claire Moxham, Sally A. Kenny, Ben Fanson
Globally, river regulation and water extraction for anthropogenic use have altered the hydrology and ecology of riverine and floodplain ecosystems. Managed environmental flows are increasingly being implemented to restore the condition of many riverine and floodplain ecosystems. In the Murray-Darling River Basin, south-eastern Australia, appropriate flooding regimes are key to maintaining populations of the dominant floodplain forests and woodland trees, River Red Gum (Eucalyptus camaldulensis) and Black Box (E. largiflorens). We investigated the effects of three environmental flow events and microsite attributes (bare ground, canopy and understorey vegetation) on eucalypt recruitment over a five-year period across a semi-arid floodplain gradient (lake bed, lower and higher floodplain). Eucalypt recruitment increased after the environmental flows. The probability of recruitment declined with increasing elevation along the floodplain gradient, with the highest occurrence on the lake bed and lower floodplain where River Red Gum dominates. Recruitment on the higher floodplain, where Black Box is dominant, was low, suggesting that factors other than flooding (e.g. poor tree health) may limit regeneration. Recruitment also increased with increasing cover of bare ground and understorey vegetation. Saplings (>1 m) were more likely to occur on the lower floodplain, where understorey vegetation cover approached 50 %, suggesting that the germination and survival niches of eucalypts may differ. That is, bare ground is necessary for germination, while understorey vegetation may provide protection to seedlings from desiccation and browsing. The combined flood events likely benefited the survival of pre-established seedlings by limiting the effects of summer desiccation and increasing soil moisture availability. There may be a trade-off between managing environmental flows for seed germination versus seedling survival. Future environmental flows that target the higher floodplain are likely to contribute to improvements in tree health, reproductive output and subsequent recruitment opportunities in this floodplain ecosystem. This study shows that environmental flows likely contribute to the maintenance of sustainable eucalypt floodplain forests and woodlands through the facilitation of recruitment and seedling persistence.
{"title":"Environmental flows and microsite attributes influence floodplain eucalypt recruitment","authors":"Claire Moxham, Sally A. Kenny, Ben Fanson","doi":"10.1016/j.foreco.2024.122330","DOIUrl":"10.1016/j.foreco.2024.122330","url":null,"abstract":"<div><div>Globally, river regulation and water extraction for anthropogenic use have altered the hydrology and ecology of riverine and floodplain ecosystems. Managed environmental flows are increasingly being implemented to restore the condition of many riverine and floodplain ecosystems. In the Murray-Darling River Basin, south-eastern Australia, appropriate flooding regimes are key to maintaining populations of the dominant floodplain forests and woodland trees, River Red Gum (<em>Eucalyptus camaldulensis</em>) and Black Box (<em>E. largiflorens</em>). We investigated the effects of three environmental flow events and microsite attributes (bare ground, canopy and understorey vegetation) on eucalypt recruitment over a five-year period across a semi-arid floodplain gradient (lake bed, lower and higher floodplain). Eucalypt recruitment increased after the environmental flows. The probability of recruitment declined with increasing elevation along the floodplain gradient, with the highest occurrence on the lake bed and lower floodplain where River Red Gum dominates. Recruitment on the higher floodplain, where Black Box is dominant, was low, suggesting that factors other than flooding (e.g. poor tree health) may limit regeneration. Recruitment also increased with increasing cover of bare ground and understorey vegetation. Saplings (>1 m) were more likely to occur on the lower floodplain, where understorey vegetation cover approached 50 %, suggesting that the germination and survival niches of eucalypts may differ. That is, bare ground is necessary for germination, while understorey vegetation may provide protection to seedlings from desiccation and browsing. The combined flood events likely benefited the survival of pre-established seedlings by limiting the effects of summer desiccation and increasing soil moisture availability. There may be a trade-off between managing environmental flows for seed germination versus seedling survival. Future environmental flows that target the higher floodplain are likely to contribute to improvements in tree health, reproductive output and subsequent recruitment opportunities in this floodplain ecosystem. This study shows that environmental flows likely contribute to the maintenance of sustainable eucalypt floodplain forests and woodlands through the facilitation of recruitment and seedling persistence.</div></div>","PeriodicalId":12350,"journal":{"name":"Forest Ecology and Management","volume":"572 ","pages":"Article 122330"},"PeriodicalIF":3.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532544","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}
Pub Date : 2024-10-18DOI: 10.1016/j.foreco.2024.122334
Vicent A. Ribas-Costa , Aitor Gastón , Sean A. Bloszies , Jesse D. Henderson , Andrew Trlica , David R. Carter , Rafael Rubilar , Timothy J. Albaugh , Rachel L. Cook
Forest productivity is one of the most important aspects of forest management, landscape planning, and climate change assessment. However, although there are multiple elements known to affect productivity, most of them rely on the “nature” of the edaphic, climatic, and geographic conditions, and only some specific aspects can be modified through forest management or “nurture”. Through evaluation of site resource availability and an understanding of the main drivers of productivity, management can present solutions to overcome site resource limitations to productivity. Therefore, understanding the implications of a specific management regime requires understanding what drives productivity across large spatial extents and among different management regimes. In this study, we used data from over 1 million hectares of industrial forestland, covering over 6000 different soils and several management regimes of Pinus taeda L. plantations, as well as plot-based data from the Forest Inventory and Analysis (FIA) program, facilitating a comparison of planted and natural Pinus taeda stands. Combined with US Geological Survey LiDAR data, we computed site index and generated wall-to-wall productivity maps for planted Pinus taeda stands in the southeastern US, as well as point-based site index estimates for the FIA dataset. We modeled site index using a random forest algorithm considering edaphic, geologic, and physiographic province information based on the Forest Productivity Cooperative “SPOT” system, and also included climate and management history data. Our model predicted site index with an R2 of 0.701 and RMSE of 1.41 m on the industrial data and R2 of 0.417 and RMSE of 1.84 m for the FIA data. We found that year of establishment of the forest, physiographic province, and geology, were the most important drivers of site index. The soil classification modifier indicating root restrictions were the most important soil-specific variable. Additionally, we found an average increase in site index of 3.05 m since the 1950s for all FIA data, and an average increase of 4.73 m for all industrial data since the 1970s. For the latest period analyzed (2000–2012), average site index in planted FIA plots was 1.2 m higher than naturally regenerated FIA plots, and site index in all industrial forestland had a site index almost 3 m greater than planted FIA plots. Overall, we believe this work sets the foundation for better understanding of forest productivity and highlights the importance of intensive silviculture to improve productivity, and as an additional tool to achieve the economic, environmental, and social objectives.
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