Aims The aim of this study was to analyze changes in emission of water-soluble ions in fine particulate matter over time and in different southwest forest areas in China based on China’s Forestry Statistical Yearbook and MODIS satellite fire point data. Methods We took 6 dominant tree species samples in the southwestern forest region of China and simulated combustion using controllable biomass combustion devices. Based on the spatial analysis method of ArcGIS, combining satellite fire point data and official statistical yearbooks, we analyzed the spatial and temporal dynamics of emissions of water-soluble ions in PM2.5 released by forest fires in southwestern forest areas from 2004 to 2021. Results The total amount of forest biomass combusted in southwest forest areas was 64.43 kt. Among the different forest types, the proportion of burnt subtropical evergreen broad-leaved forest was the largest (60.49%) followed by subtropical mixed coniferous and broad-leaved forest (22.78%) and subtropical evergreen coniferous forest (16.72%). During the study period, 61.19 t of water-soluble ions were released in PM 2.5 from forest fires, and the emissions of Li + , Na + , NH 4 + , K + , Mg 2+ , Ca 2+ , F − , Cl − , Br − , NO 3 − , PO 4 3− and SO 4 2− were 0.48 t, 11.54 t, 2.51 t, 19.44 t, 2.12 t, 2.92 t, 1.94 t, 12.70 t, 1.12 t, 1.18 t, 1.17 t and 4.07 t, respectively. Yunnan was the province with the highest emissions of water-soluble ions in PM 2.5 in the southwest forest areas, and the concentration K + was the highest. Emission of water-soluble ions in Yunnan and Sichuan all showed a significant downward trend, while the overall decrease in Tibet, Chongqing and Guizhou was not significant. The peak emission of water-soluble ions in PM 2.5 during forest fires appeared in spring and winter, which accounted for 87.66% of the total emission. Discussion This study reveals the spatiotemporal changes in water-soluble ion emissions from forest fires, by studying the spatiotemporal dynamics of water-soluble ions in PM 2.5 , we can better understand the sources, distribution, and change patterns of these ions, as well as their impact on the atmospheric environment, ecosystems, and climate change. This information is crucial for predicting and managing air pollution, as well as developing effective forest management and environmental protection policies to respond to fires; and hence concerted fire prevention efforts should be made in each province, taking into account the season with higher probability of fire occurrence to reduce the potential impact of fire-related pollutions.
{"title":"Temporal and spatial dynamics in emission of water-soluble ions in fine particulate matter during forest fires in Southwest China","authors":"Xiaoyu Zhan, Yuanfan Ma, Ziyan Huang, Chenyue Zheng, Haichuan Lin, Mulualem Tigabu, Futao Guo","doi":"10.3389/ffgc.2023.1250038","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1250038","url":null,"abstract":"Aims The aim of this study was to analyze changes in emission of water-soluble ions in fine particulate matter over time and in different southwest forest areas in China based on China’s Forestry Statistical Yearbook and MODIS satellite fire point data. Methods We took 6 dominant tree species samples in the southwestern forest region of China and simulated combustion using controllable biomass combustion devices. Based on the spatial analysis method of ArcGIS, combining satellite fire point data and official statistical yearbooks, we analyzed the spatial and temporal dynamics of emissions of water-soluble ions in PM2.5 released by forest fires in southwestern forest areas from 2004 to 2021. Results The total amount of forest biomass combusted in southwest forest areas was 64.43 kt. Among the different forest types, the proportion of burnt subtropical evergreen broad-leaved forest was the largest (60.49%) followed by subtropical mixed coniferous and broad-leaved forest (22.78%) and subtropical evergreen coniferous forest (16.72%). During the study period, 61.19 t of water-soluble ions were released in PM 2.5 from forest fires, and the emissions of Li + , Na + , NH 4 + , K + , Mg 2+ , Ca 2+ , F − , Cl − , Br − , NO 3 − , PO 4 3− and SO 4 2− were 0.48 t, 11.54 t, 2.51 t, 19.44 t, 2.12 t, 2.92 t, 1.94 t, 12.70 t, 1.12 t, 1.18 t, 1.17 t and 4.07 t, respectively. Yunnan was the province with the highest emissions of water-soluble ions in PM 2.5 in the southwest forest areas, and the concentration K + was the highest. Emission of water-soluble ions in Yunnan and Sichuan all showed a significant downward trend, while the overall decrease in Tibet, Chongqing and Guizhou was not significant. The peak emission of water-soluble ions in PM 2.5 during forest fires appeared in spring and winter, which accounted for 87.66% of the total emission. Discussion This study reveals the spatiotemporal changes in water-soluble ion emissions from forest fires, by studying the spatiotemporal dynamics of water-soluble ions in PM 2.5 , we can better understand the sources, distribution, and change patterns of these ions, as well as their impact on the atmospheric environment, ecosystems, and climate change. This information is crucial for predicting and managing air pollution, as well as developing effective forest management and environmental protection policies to respond to fires; and hence concerted fire prevention efforts should be made in each province, taking into account the season with higher probability of fire occurrence to reduce the potential impact of fire-related pollutions.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135854007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-13DOI: 10.3389/ffgc.2023.1206225
Ming Yang Lee, Kelly M. Andersen
Many ecosystem processes revolve around plant roots and the rhizosphere, but root trait knowledge has generally lagged behind aboveground plant traits from leaves and stems. In particular, root trait representation of Paleotropical species and tropical communities in modern trait databases remains poor, constraining our understanding of belowground processes in these regions. Therefore, we sought to examine the current state of root trait representation and associated topics in the Paleotropics to identify gaps and biases in the existing literature. Using an exhaustive literature scan, we compiled a list of publications that contained various belowground trait information. Subsequently, we utilized a statistical topic modeling method to analyze abstracts of publications in order to identify topics studied alongside root trait documentation. Finally, we consolidated trends in root trait coverage and topics across five geographical regions and four time periods to illustrate shifts in literature and knowledge of ecological processes revolving around roots. Root trait representation was heavily biased toward root biomass but other aspects of root systems such as physiology, architecture and anatomical traits remain underrepresented. We categorized 23 unique topics around root trait literature across eight categories: ecosystem productivity and biomass stocks, plant functional traits, resource availability, ecosystem processes and dynamics, mycorrhizal colonization, edaphic processes, seedling experiments, and global change and variation. Traits and topic coverage were unequally distributed across the Paletropics and exhibited a notable shift in focus from resource limitation and mycorrhizae research to root trait variation at large spatial and temporal scales over the last 50 years of root trait literature. Given these trends and the heterogenous effects global change exerts on the tropics at a regional scale, we provided several recommendations to facilitate inter-study comparisons of traits to advance the field’s understanding of belowground ecosystem processes in pantropical communities.
{"title":"Global root trait underrepresentation in Paleotropical communities: a qualitative analysis","authors":"Ming Yang Lee, Kelly M. Andersen","doi":"10.3389/ffgc.2023.1206225","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1206225","url":null,"abstract":"Many ecosystem processes revolve around plant roots and the rhizosphere, but root trait knowledge has generally lagged behind aboveground plant traits from leaves and stems. In particular, root trait representation of Paleotropical species and tropical communities in modern trait databases remains poor, constraining our understanding of belowground processes in these regions. Therefore, we sought to examine the current state of root trait representation and associated topics in the Paleotropics to identify gaps and biases in the existing literature. Using an exhaustive literature scan, we compiled a list of publications that contained various belowground trait information. Subsequently, we utilized a statistical topic modeling method to analyze abstracts of publications in order to identify topics studied alongside root trait documentation. Finally, we consolidated trends in root trait coverage and topics across five geographical regions and four time periods to illustrate shifts in literature and knowledge of ecological processes revolving around roots. Root trait representation was heavily biased toward root biomass but other aspects of root systems such as physiology, architecture and anatomical traits remain underrepresented. We categorized 23 unique topics around root trait literature across eight categories: ecosystem productivity and biomass stocks, plant functional traits, resource availability, ecosystem processes and dynamics, mycorrhizal colonization, edaphic processes, seedling experiments, and global change and variation. Traits and topic coverage were unequally distributed across the Paletropics and exhibited a notable shift in focus from resource limitation and mycorrhizae research to root trait variation at large spatial and temporal scales over the last 50 years of root trait literature. Given these trends and the heterogenous effects global change exerts on the tropics at a regional scale, we provided several recommendations to facilitate inter-study comparisons of traits to advance the field’s understanding of belowground ecosystem processes in pantropical communities.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"42 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135854604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-12DOI: 10.3389/ffgc.2023.1198156
Alexandra R. Lalor, Darin J. Law, David D. Breshears, Donald A. Falk, Jason P. Field, Rachel A. Loehman, F. Jack Triepke, Greg A. Barron-Gafford
Tree loss is increasing rapidly due to drought- and heat-related mortality and intensifying fire activity. Consequently, the fate of many forests depends on the ability of juvenile trees to withstand heightened climate and disturbance anomalies. Extreme climatic events, such as droughts and heatwaves, are increasing in frequency and severity, and trees in mountainous regions must contend with these landscape-level climate episodes. Recent research focuses on how mortality of individual tree species may be driven by drought and heatwaves, but how juvenile mortality under these conditions would vary among species spanning an elevational gradient—given concurrent variation in climate, ecohydrology, and physiology–remains unclear. We address this knowledge gap by implementing a growth chamber study, imposing extreme drought with and without a compounding heatwave, for juveniles of five species that span a forested life zones in the Southwestern United States. Overall, the length of a progressive drought required to trigger mortality differed by up to 20 weeks among species. Inclusion of a heatwave hastened mean time to mortality for all species by about 1 week. Lower-elevation species that grow in warmer ambient conditions died earlier ( Pinus ponderosa in 10 weeks, Pinus edulis in 14 weeks) than did higher-elevation species from cooler ambient conditions ( Picea engelmannii and Pseudotsuga menziesii in 19 weeks, and Pinus flexilis in 30 weeks). When exposed to a heatwave in conjunction with drought, mortality advanced significantly only for species from cooler ambient conditions ( Pinus flexilis : 2.7 weeks earlier; Pseudotsuga menziesii : 2.0 weeks earlier). Cooler ambient temperatures may have buffered against moisture loss during drought, resulting in longer survival of higher-elevation species despite expected drought tolerance of lower-elevation species due to tree physiology. Our study suggests that droughts will play a leading role in juvenile tree mortality and will most directly impact species at warmer climate thresholds, with heatwaves in tandem with drought potentially exacerbating mortality especially of high elevation species. These responses are relevant for assessing the potential success of both natural and managed reforestation, as differential juvenile survival following episodic extreme events will determine future landscape-scale vegetation trajectories under changing climate.
{"title":"Mortality thresholds of juvenile trees to drought and heatwaves: implications for forest regeneration across a landscape gradient","authors":"Alexandra R. Lalor, Darin J. Law, David D. Breshears, Donald A. Falk, Jason P. Field, Rachel A. Loehman, F. Jack Triepke, Greg A. Barron-Gafford","doi":"10.3389/ffgc.2023.1198156","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1198156","url":null,"abstract":"Tree loss is increasing rapidly due to drought- and heat-related mortality and intensifying fire activity. Consequently, the fate of many forests depends on the ability of juvenile trees to withstand heightened climate and disturbance anomalies. Extreme climatic events, such as droughts and heatwaves, are increasing in frequency and severity, and trees in mountainous regions must contend with these landscape-level climate episodes. Recent research focuses on how mortality of individual tree species may be driven by drought and heatwaves, but how juvenile mortality under these conditions would vary among species spanning an elevational gradient—given concurrent variation in climate, ecohydrology, and physiology–remains unclear. We address this knowledge gap by implementing a growth chamber study, imposing extreme drought with and without a compounding heatwave, for juveniles of five species that span a forested life zones in the Southwestern United States. Overall, the length of a progressive drought required to trigger mortality differed by up to 20 weeks among species. Inclusion of a heatwave hastened mean time to mortality for all species by about 1 week. Lower-elevation species that grow in warmer ambient conditions died earlier ( Pinus ponderosa in 10 weeks, Pinus edulis in 14 weeks) than did higher-elevation species from cooler ambient conditions ( Picea engelmannii and Pseudotsuga menziesii in 19 weeks, and Pinus flexilis in 30 weeks). When exposed to a heatwave in conjunction with drought, mortality advanced significantly only for species from cooler ambient conditions ( Pinus flexilis : 2.7 weeks earlier; Pseudotsuga menziesii : 2.0 weeks earlier). Cooler ambient temperatures may have buffered against moisture loss during drought, resulting in longer survival of higher-elevation species despite expected drought tolerance of lower-elevation species due to tree physiology. Our study suggests that droughts will play a leading role in juvenile tree mortality and will most directly impact species at warmer climate thresholds, with heatwaves in tandem with drought potentially exacerbating mortality especially of high elevation species. These responses are relevant for assessing the potential success of both natural and managed reforestation, as differential juvenile survival following episodic extreme events will determine future landscape-scale vegetation trajectories under changing climate.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136014355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-12DOI: 10.3389/ffgc.2023.1259500
Qian Zhang, Rong Wang
Although Chinese society has transformed into the digital age, carbon peaking and neutrality are still important starting points for implementing the national strategy of green and low-carbon integrated growth in the Yangtze River Delta (YRD) of China. With data from 41 cities in YRD from 2005 to 2019, this paper empirically analyzes the carbon emission reduction effects from dual perspectives of forest resource endowment and low-carbon pilot policy in the digital age. The findings include: (1) Forest resources are indeed conducive to reducing carbon emissions. However, when considering the carbon sequestration effect of forests, a nonlinear U-shaped relationship exists between forest resource abundance and net carbon emissions per GDP. (2) Low-carbon city pilot policies are effective in reducing carbon emissions. (3) Low-carbon pilot policies perform better in smart cities, resource-based cities, and cities with abundant forest resources, showing significant heterogeneity. Forests can be relied on to assist in carbon emission reduction in the short term, but in the long term, a forest ecosystem with biodiversity is needed to achieve low-carbon sustainable development. This article provides some experience and references for building green and carbon-neutral cities for YRD in the digital age.
{"title":"Carbon emission reduction effects in Yangtze River Delta from the dual perspectives of forest resource endowment and low-carbon pilot policy in the digital age","authors":"Qian Zhang, Rong Wang","doi":"10.3389/ffgc.2023.1259500","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1259500","url":null,"abstract":"Although Chinese society has transformed into the digital age, carbon peaking and neutrality are still important starting points for implementing the national strategy of green and low-carbon integrated growth in the Yangtze River Delta (YRD) of China. With data from 41 cities in YRD from 2005 to 2019, this paper empirically analyzes the carbon emission reduction effects from dual perspectives of forest resource endowment and low-carbon pilot policy in the digital age. The findings include: (1) Forest resources are indeed conducive to reducing carbon emissions. However, when considering the carbon sequestration effect of forests, a nonlinear U-shaped relationship exists between forest resource abundance and net carbon emissions per GDP. (2) Low-carbon city pilot policies are effective in reducing carbon emissions. (3) Low-carbon pilot policies perform better in smart cities, resource-based cities, and cities with abundant forest resources, showing significant heterogeneity. Forests can be relied on to assist in carbon emission reduction in the short term, but in the long term, a forest ecosystem with biodiversity is needed to achieve low-carbon sustainable development. This article provides some experience and references for building green and carbon-neutral cities for YRD in the digital age.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135969082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-12DOI: 10.3389/ffgc.2023.1260327
Zhaobin Mu, Jianqiang Zeng, Yanli Zhang, Wei Song, Weihua Pang, Zhigang Yi, Dolores Asensio, Joan Llusià, Josep Peñuelas, Xinming Wang
The exchange of isoprenoids, which includes isoprene, monoterpenes, and sesquiterpenes, between ecosystem soils and the atmosphere plays a significant role in soil ecology and atmospheric chemistry. However, research on flux exchange rates in subtropical ecosystems has been limited, as previous studies have mainly focused on temperate and boreal environments. In this study, we aimed to quantify the exchange of isoprenoids between the soil (with or without surface litter) and the atmosphere in a subtropical Eucalyptus urophylla plantation forest during the daytime in the wet season of subtropical China. Additionally, we investigated the influence of soil and litter variables on the fluxes of isoprenoids. Our results unveiled the exchange of isoprene and 17 terpenoid compounds, comprising 11 monoterpenes and 6 sesquiterpenes, between the studied soils and the atmosphere. Interestingly, regardless of the presence of surface litter, the studied soils acted as net sinks for isoprenoids, with isoprene being the most absorbed compound (−71.84 ± 8.26 μg m −2 h −1 ). The removal of surface litter had a significant impact on the exchange rates of two monoterpenes (α-pinene and β-pinene), resulting in decreased fluxes. Furthermore, the exchange rates of isoprene were positively correlated with litter dry weight and negatively correlated with soil temperature. The higher exchange rates of monoterpenes and sesquiterpenes were associated with increased levels of soil respiration and the abundance of leaf litter. These findings suggest that, in the context of projected global warming scenarios, the capacity of subtropical soils to act as sinks for isoprenoids is expected to increase in subtropical China. These changes in sink capacity may have implications for regional-scale atmospheric chemistry and ecosystem functioning.
类异戊二烯包括异戊二烯、单萜和倍半萜，它们在生态系统土壤和大气之间的交换在土壤生态学和大气化学中起着重要的作用。然而，由于以往的研究主要集中在温带和北方环境，对亚热带生态系统通量交换率的研究还很有限。在本研究中，我们旨在量化亚热带尾叶桉人工林在雨季白天土壤(有或没有地表凋落物)与大气之间的类异戊二烯交换。此外，我们还研究了土壤和凋落物变量对类异戊二烯通量的影响。我们的研究结果揭示了异戊二烯和17种萜类化合物，包括11种单萜类和6种倍半萜类，在所研究的土壤和大气之间的交换。有趣的是，无论地表是否存在凋落物，所研究的土壤都是类异戊二烯的净汇，其中异戊二烯是吸收最多的化合物(- 71.84±8.26 μg m - 2 h - 1)。表面凋落物的去除对两种单萜(α-蒎烯和β-蒎烯)的交换速率有显著影响，导致通量降低。异戊二烯交换速率与凋落物干重呈正相关，与土壤温度负相关。单萜类和倍半萜类的较高交换速率与土壤呼吸水平和凋落叶丰度的增加有关。这些发现表明，在预估的全球变暖情景下，中国亚热带土壤作为类异戊二烯汇的能力预计会增加。这些汇容量的变化可能对区域尺度的大气化学和生态系统功能产生影响。
{"title":"Soil uptake of isoprenoids in a Eucalyptus urophylla plantation forest in subtropical China","authors":"Zhaobin Mu, Jianqiang Zeng, Yanli Zhang, Wei Song, Weihua Pang, Zhigang Yi, Dolores Asensio, Joan Llusià, Josep Peñuelas, Xinming Wang","doi":"10.3389/ffgc.2023.1260327","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1260327","url":null,"abstract":"The exchange of isoprenoids, which includes isoprene, monoterpenes, and sesquiterpenes, between ecosystem soils and the atmosphere plays a significant role in soil ecology and atmospheric chemistry. However, research on flux exchange rates in subtropical ecosystems has been limited, as previous studies have mainly focused on temperate and boreal environments. In this study, we aimed to quantify the exchange of isoprenoids between the soil (with or without surface litter) and the atmosphere in a subtropical Eucalyptus urophylla plantation forest during the daytime in the wet season of subtropical China. Additionally, we investigated the influence of soil and litter variables on the fluxes of isoprenoids. Our results unveiled the exchange of isoprene and 17 terpenoid compounds, comprising 11 monoterpenes and 6 sesquiterpenes, between the studied soils and the atmosphere. Interestingly, regardless of the presence of surface litter, the studied soils acted as net sinks for isoprenoids, with isoprene being the most absorbed compound (−71.84 ± 8.26 μg m −2 h −1 ). The removal of surface litter had a significant impact on the exchange rates of two monoterpenes (α-pinene and β-pinene), resulting in decreased fluxes. Furthermore, the exchange rates of isoprene were positively correlated with litter dry weight and negatively correlated with soil temperature. The higher exchange rates of monoterpenes and sesquiterpenes were associated with increased levels of soil respiration and the abundance of leaf litter. These findings suggest that, in the context of projected global warming scenarios, the capacity of subtropical soils to act as sinks for isoprenoids is expected to increase in subtropical China. These changes in sink capacity may have implications for regional-scale atmospheric chemistry and ecosystem functioning.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135968032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-11DOI: 10.3389/ffgc.2023.1135270
Nanette C. Raczka, Qian Yi Ho, Vupasana Srinivasan, Ming Yang Lee, Chung-Wing Ko, Madeleine Königer, Terence Chua, Delia Binny, Kang Min Ngo, Kelly M. Andersen
Tropical forests play a crucial role in mediating the global carbon cycle and climate. Southeast Asian tropical forests are experiencing ongoing threats of deforestation and degradation. There is an urgent need to determine how the conversion from primary forest to secondary forest coverage may impact C stocks and cycling. While old-growth forests typically contain larger stores of C aboveground than secondary forests, past research has found varied results for belowground soil C storage and fluxes between tropical forest types. We examined differences in annual soil C efflux in a 2-ha old-growth and an adjacent 2-ha 70-year-old secondary ForestGEO plots in Bukit Timah Nature Reserve in Singapore. We hypothesized that the secondary forest would have greater soil C efflux rates than the old-growth forest and explored several potential drivers of soil C efflux including abiotic and biotic factors such as soil moisture, fine root biomass, and ectomycorrhizal association. We found that the hypothesis was supported, suggesting that belowground carbon dynamics fundamentally differ with forest age. Additionally, we found that fine root biomass was the best predictor of soil C efflux in the secondary forest and soil moisture in the old-growth forest. The difference in soil C efflux between forest types indicates that with continued degradation of old-growth forests in Southeast Asia, conversion of old-growth forests into secondary forests may drive greater C loss from soils even after 70 years of regrowth.
{"title":"Greater soil carbon losses from secondary than old-growth tropical forests","authors":"Nanette C. Raczka, Qian Yi Ho, Vupasana Srinivasan, Ming Yang Lee, Chung-Wing Ko, Madeleine Königer, Terence Chua, Delia Binny, Kang Min Ngo, Kelly M. Andersen","doi":"10.3389/ffgc.2023.1135270","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1135270","url":null,"abstract":"Tropical forests play a crucial role in mediating the global carbon cycle and climate. Southeast Asian tropical forests are experiencing ongoing threats of deforestation and degradation. There is an urgent need to determine how the conversion from primary forest to secondary forest coverage may impact C stocks and cycling. While old-growth forests typically contain larger stores of C aboveground than secondary forests, past research has found varied results for belowground soil C storage and fluxes between tropical forest types. We examined differences in annual soil C efflux in a 2-ha old-growth and an adjacent 2-ha 70-year-old secondary ForestGEO plots in Bukit Timah Nature Reserve in Singapore. We hypothesized that the secondary forest would have greater soil C efflux rates than the old-growth forest and explored several potential drivers of soil C efflux including abiotic and biotic factors such as soil moisture, fine root biomass, and ectomycorrhizal association. We found that the hypothesis was supported, suggesting that belowground carbon dynamics fundamentally differ with forest age. Additionally, we found that fine root biomass was the best predictor of soil C efflux in the secondary forest and soil moisture in the old-growth forest. The difference in soil C efflux between forest types indicates that with continued degradation of old-growth forests in Southeast Asia, conversion of old-growth forests into secondary forests may drive greater C loss from soils even after 70 years of regrowth.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136210338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-10DOI: 10.3389/ffgc.2023.1215713
W. Spencer Peay, Bronson P. Bullock, Cristian R. Montes
Growth and yield models are essential tools in modern forestry, especially for intensively managed loblolly pine plantations in the southeastern United States. While model developers often have a good idea of where these models should be used with respect to geographic location, determining geographic bounds for model usage can be daunting. Such bounds provide suitable areas where model predictions are likely to behave as expected or identify areas where models may do a poor job of characterizing the growth of a resource. In this research, we adapted a niche model methodology, commonly used to identify suitable spots for species occurrence (maximum entropy), to identify areas for using growth and yield models built from plots established in the Lower Coastal Plain and Piedmont/Upper Coastal Plain in the southeastern United States. The results from this analysis identify areas with similar climatic envelopes and soil properties to the areas where data was collected to fit these growth and yield models. These areas show notable overlap with the areas prescribed for use by the evaluated growth and yield models and support practitioners use of these models throughout these regions. Furthermore, this methodology can be applied to different forest models built using large regional extents as long as climatic and soil values are available for each site.
{"title":"A maximum entropy approach to defining geographic bounds on growth and yield model usage","authors":"W. Spencer Peay, Bronson P. Bullock, Cristian R. Montes","doi":"10.3389/ffgc.2023.1215713","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1215713","url":null,"abstract":"Growth and yield models are essential tools in modern forestry, especially for intensively managed loblolly pine plantations in the southeastern United States. While model developers often have a good idea of where these models should be used with respect to geographic location, determining geographic bounds for model usage can be daunting. Such bounds provide suitable areas where model predictions are likely to behave as expected or identify areas where models may do a poor job of characterizing the growth of a resource. In this research, we adapted a niche model methodology, commonly used to identify suitable spots for species occurrence (maximum entropy), to identify areas for using growth and yield models built from plots established in the Lower Coastal Plain and Piedmont/Upper Coastal Plain in the southeastern United States. The results from this analysis identify areas with similar climatic envelopes and soil properties to the areas where data was collected to fit these growth and yield models. These areas show notable overlap with the areas prescribed for use by the evaluated growth and yield models and support practitioners use of these models throughout these regions. Furthermore, this methodology can be applied to different forest models built using large regional extents as long as climatic and soil values are available for each site.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136296144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-09DOI: 10.3389/ffgc.2023.1215701
Sergio Diez-Hermano, Jorge Poveda, Jonatan Niño-Sanchez, Irene Teresa Bocos-Asenjo, Álvaro Peix, Pablo Martín-Pinto, Julio Javier Diez
Introduction Forests in the Mediterranean basin are currently in decline. Their resilience has been eroded as a result of climate change and anthropogenic impacts, making them vulnerable to increasingly frequent episodes of drought, fire and the spread of pests and diseases. The impact of these natural and anthropogenic events on soil biodiversity is of particular concern, as the soil fungal community plays a key role in ecosystem homeostasis. Objectives and methods In order to analyse the relationship between soil health status and fungal diversity, soil samples were collected from declining Mediterranean forests of Castanea sativa (chestnut), Quercus ilex (holm oak), Quercus suber (cork oak) and Quercus pyrenaica (Pyrenean oak). A metabarcoding study was carried out by sequencing the ITS genomic region. Results A total of 674 fungal genera were found. It has not been possible to explain the differences in health status from the fungal genera found exclusively on declining forest soils, as none of them have been described as pathogenic. Healthy chestnut soils were characterized by a high alpha diversity and a higher abundance of the genus Metarhizium . No differentially abundant genera were found in any of the other forest species tested. Declining chestnut soils harbored more abundance of ectomycorrhizae and soil saprotrophs than healthy samples. Ectomycorrhizae were the dominant lifestyle in all oak species regardless of health status, whereas arbuscular mycorrhizae were preferentially found in declining cork oak soils. Discussion This work highlights the resilience of fungal communities of soil against decline and highlights the need to further investigate its relationship with the forest’s ability to cope with the challenges of climate change.
{"title":"Rhizosphere mycobiome diversity in four declining Mediterranean tree species","authors":"Sergio Diez-Hermano, Jorge Poveda, Jonatan Niño-Sanchez, Irene Teresa Bocos-Asenjo, Álvaro Peix, Pablo Martín-Pinto, Julio Javier Diez","doi":"10.3389/ffgc.2023.1215701","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1215701","url":null,"abstract":"Introduction Forests in the Mediterranean basin are currently in decline. Their resilience has been eroded as a result of climate change and anthropogenic impacts, making them vulnerable to increasingly frequent episodes of drought, fire and the spread of pests and diseases. The impact of these natural and anthropogenic events on soil biodiversity is of particular concern, as the soil fungal community plays a key role in ecosystem homeostasis. Objectives and methods In order to analyse the relationship between soil health status and fungal diversity, soil samples were collected from declining Mediterranean forests of Castanea sativa (chestnut), Quercus ilex (holm oak), Quercus suber (cork oak) and Quercus pyrenaica (Pyrenean oak). A metabarcoding study was carried out by sequencing the ITS genomic region. Results A total of 674 fungal genera were found. It has not been possible to explain the differences in health status from the fungal genera found exclusively on declining forest soils, as none of them have been described as pathogenic. Healthy chestnut soils were characterized by a high alpha diversity and a higher abundance of the genus Metarhizium . No differentially abundant genera were found in any of the other forest species tested. Declining chestnut soils harbored more abundance of ectomycorrhizae and soil saprotrophs than healthy samples. Ectomycorrhizae were the dominant lifestyle in all oak species regardless of health status, whereas arbuscular mycorrhizae were preferentially found in declining cork oak soils. Discussion This work highlights the resilience of fungal communities of soil against decline and highlights the need to further investigate its relationship with the forest’s ability to cope with the challenges of climate change.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135093861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Introduction Forests play a crucial role in the lives of millions of people worldwide by providing material and non-material contributions. Despite forests’ paramount importance from ecological, economic, and cultural perspectives, the long-term relationship between forests and local communities living in their proximity is often an undervalued contribution to our understanding of local ecological knowledge systems and forest changes. Methods We studied the interrelationships between the Mandinka peoples and forests in an understudied area of West Africa, the Gambia’s Lower River Region (LRR). Through 35 semi-structured interviews, we documented the forests’ contributions to local Mandinka peoples and their perception of forest changes. We also used geographic information systems (GIS software) for remote sensing satellite imagery to establish a baseline for these complex connections and changes. Results This research revealed the crucial importance of the forest’s contributions to Mandinka communities and specifically to their psychological well-being. In addition, the interviewees revealed how ongoing socio-economic changes are affecting the human-forest relationship and possibly eroding the local ethnoforestry knowledge in the LRR of the Gambia. The most common forest contributions are those that provide material goods, serving as the driving force in connecting people with the forest, while non-material contributions are eroding due to complex socio-economic changes. Major socio-economic changes are also believed to drive the shift from dense forest to mixed forest and grassland. Discussion In line with the state of the art, the knowledge and perception of changes documented in this article underline the quintessential need to include local communities’ views in shaping forest management, in order to better fine-tune the strategies to safeguard biocultural diversity across forest areas.
{"title":"“Forest is integral to life”: people-forest relations in the lower river region, the Gambia","authors":"Sarata Darboe, Lamin Manneh, Nataliya Stryamets, Baiba Prūse, Andrea Pieroni, Renata Sõukand, Giulia Mattalia","doi":"10.3389/ffgc.2023.1181013","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1181013","url":null,"abstract":"Introduction Forests play a crucial role in the lives of millions of people worldwide by providing material and non-material contributions. Despite forests’ paramount importance from ecological, economic, and cultural perspectives, the long-term relationship between forests and local communities living in their proximity is often an undervalued contribution to our understanding of local ecological knowledge systems and forest changes. Methods We studied the interrelationships between the Mandinka peoples and forests in an understudied area of West Africa, the Gambia’s Lower River Region (LRR). Through 35 semi-structured interviews, we documented the forests’ contributions to local Mandinka peoples and their perception of forest changes. We also used geographic information systems (GIS software) for remote sensing satellite imagery to establish a baseline for these complex connections and changes. Results This research revealed the crucial importance of the forest’s contributions to Mandinka communities and specifically to their psychological well-being. In addition, the interviewees revealed how ongoing socio-economic changes are affecting the human-forest relationship and possibly eroding the local ethnoforestry knowledge in the LRR of the Gambia. The most common forest contributions are those that provide material goods, serving as the driving force in connecting people with the forest, while non-material contributions are eroding due to complex socio-economic changes. Major socio-economic changes are also believed to drive the shift from dense forest to mixed forest and grassland. Discussion In line with the state of the art, the knowledge and perception of changes documented in this article underline the quintessential need to include local communities’ views in shaping forest management, in order to better fine-tune the strategies to safeguard biocultural diversity across forest areas.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135095812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2023-10-06DOI: 10.3389/ffgc.2023.1166349
Jiayuan Lin, Decao Chen, Shuai Yang, Xiaohan Liao
Introduction Plantation forest is an important component of global forest resources. The accurate estimation of tree aboveground biomass (AGB) in plantation forest is of great significance for evaluating the carbon sequestration capacity. In recent years, UAV-borne LiDAR has been increasingly applied to forest survey, but the traditional allometric model for AGB estimation cannot be directly used without the diameter at breast height (DBH) of individual trees. Therefore, it is practicable to construct a novel allometric model incorporating the crown structure parameters, which can be precisely extracted from UAV LiDAR data. Additionally, the reduction effect of adjacent trees on crown area (A c ) should be taken into account. Methods In this study, we proposed an allometric model depending on the predictor variables of A c and trunk height (H). The UAV-borne LiDAR was utilized to scan the sample plot of dawn redwood (DR) trees in the test site. The raw point cloud was first normalized and segmented into individual trees, whose A c s and Hs were sequentially extracted. To mitigate the effects of adjacent trees, the initial A c s were corrected to refer to the potential maximum A c s under undisturbed growth conditions. Finally, the corrected A c s (A cc ) and Hs were input into the constructed allometric model to achieve the AGBs of DR trees. Results and discussion According to accuracy assessment, coefficient of determination ( R 2 ) and root mean square error (RMSE) of extracted Hs were 0.9688 and 0.51 m; R 2 and RMSE of calculated AGBs were 0.9432 and 10.91 kg. The unrestricted growth parts of the tree crowns at the edge of a plantation forest could be used to derive the potential maximum A c . Compared with the allometric models for AGB estimation relying only on trunk H or on initial A c and H, the novel allometric model demonstrated superior performance in estimating the AGBs of trees in a plantation forest.
人工林是全球森林资源的重要组成部分。人工林地上生物量的准确估算对评价人工林的固碳能力具有重要意义。近年来，UAV-borne LiDAR在森林调查中的应用越来越广泛，但传统的异速生长模型无法在没有单株胸径(DBH)的情况下直接用于AGB估计。因此，构建一种包含冠状结构参数的新型异速生长模型是可行的，该模型可以从无人机激光雷达数据中精确提取。此外，还应考虑邻近树木对树冠面积(A c)的减少作用。方法利用无人机机载激光雷达(UAV-borne LiDAR)对试验区的黎明红木(DR)样地进行扫描，建立了以A c和树干高度(H)为预测变量的异速生长模型。首先将原始点云归一化并分割成独立的树，依次提取树的A、c、s和h。为了减轻邻近树木的影响，将初始碳碳比修正为未受干扰生长条件下的潜在最大碳碳比。最后，将校正后的A c s (A cc)和h输入到构建的异速生长模型中，实现DR树的agb。结果与讨论根据准确度评估，提取Hs的决定系数(r2)和均方根误差(RMSE)分别为0.9688和0.51 m;计算agb的r2和RMSE分别为0.9432和10.91 kg。人工林边缘的树冠不受限制的生长部分可以用来计算潜在的最大碳排放。与仅依赖树干H或初始A c和H的异速生长估算模型相比，该模型在估算人工林树木的AGB方面表现出更优的性能。
{"title":"Precise aboveground biomass estimation of plantation forest trees using the novel allometric model and UAV-borne LiDAR","authors":"Jiayuan Lin, Decao Chen, Shuai Yang, Xiaohan Liao","doi":"10.3389/ffgc.2023.1166349","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1166349","url":null,"abstract":"Introduction Plantation forest is an important component of global forest resources. The accurate estimation of tree aboveground biomass (AGB) in plantation forest is of great significance for evaluating the carbon sequestration capacity. In recent years, UAV-borne LiDAR has been increasingly applied to forest survey, but the traditional allometric model for AGB estimation cannot be directly used without the diameter at breast height (DBH) of individual trees. Therefore, it is practicable to construct a novel allometric model incorporating the crown structure parameters, which can be precisely extracted from UAV LiDAR data. Additionally, the reduction effect of adjacent trees on crown area (A c ) should be taken into account. Methods In this study, we proposed an allometric model depending on the predictor variables of A c and trunk height (H). The UAV-borne LiDAR was utilized to scan the sample plot of dawn redwood (DR) trees in the test site. The raw point cloud was first normalized and segmented into individual trees, whose A c s and Hs were sequentially extracted. To mitigate the effects of adjacent trees, the initial A c s were corrected to refer to the potential maximum A c s under undisturbed growth conditions. Finally, the corrected A c s (A cc ) and Hs were input into the constructed allometric model to achieve the AGBs of DR trees. Results and discussion According to accuracy assessment, coefficient of determination ( R 2 ) and root mean square error (RMSE) of extracted Hs were 0.9688 and 0.51 m; R 2 and RMSE of calculated AGBs were 0.9432 and 10.91 kg. The unrestricted growth parts of the tree crowns at the edge of a plantation forest could be used to derive the potential maximum A c . Compared with the allometric models for AGB estimation relying only on trunk H or on initial A c and H, the novel allometric model demonstrated superior performance in estimating the AGBs of trees in a plantation forest.","PeriodicalId":12538,"journal":{"name":"Frontiers in Forests and Global Change","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135351089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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