Frontiers in Forests and Global Change最新文献

{"title":"Evapotranspiration and its partitioning during and following a mountain pine beetle infestation of a lodgepole pine stand in the interior of British Columbia, Canada","authors":"Shaorong Hao, Xin Jia, Hongxian Zhao, Xinhao Li, Yanmei Mu, T. Zha, Peng Liu, C. Bourque","doi":"10.3389/ffgc.2024.1352853","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1352853","url":null,"abstract":"Massive tree mortality events in western Canada due to widespread infestation by mountain pine beetle (MPB) are expected to impact local-to-regional evapotranspiration (ET) dynamics during and after a disturbance. How ecosystem-level ET and its components may vary with canopy-tree mortality (treefall) and subsequent understory recovery remains unclear.We used 10 years of continuous eddy-covariance and remote-sensing data (2007–2016) and machine-learning models based on random forest and xgboost to determine forest- and climate-driven effects at temporal scales appropriate for a lodgepole pine-dominated stand following a major, five-year MPB disturbance initiated in the summer of 2006.Total annual ET over the 10 years ranged from 207.2 to 384.6 mm, with annual plant transpiration (T) contributing to 57 ± 5.4% (mean ± standard deviation) of annual ET. Annual ET initially declined (2007–2011) and then increased (2011–2016), with ET and T/ET increasing at statistically non-significant rates of approximately 3.2 and 1.2% per year from 2007 to 2016. Air temperature (Ta) and vapor pressure deficit (VPD) were the most important predictors of seasonal variation in ET and T/ET during the 10-year period, with high Ta, VPD, and photosynthetically active radiation (PAR) causing ET and T/ET to increase. Annual ET increased with both increasing spring Ta and decreasing VPD. Annual T/ET was shown to increase with increasing VPD and decrease with increasing volumetric soil water content at a 5-cm depth (VWC5). Enhanced vegetation index (EVI, an indicator of canopy greenness) lagged T and overstory tree mortality, whereas previous- and current-year values of EVI were shown to be poor predictors of annual ET and T/ET.These findings suggest that the promotion of climate factors on forest ecosystem-level water vapor fluxes may offset reductions promoted by MPB outbreaks. Climate processes affected water vapor fluxes more than biotic factors, like stand greenness, highlighting the need to include climate-regulatory mechanisms in predictive models of ET dynamics during and subsequent to stand disturbance. Climate and forest-greenness effects on water vapor fluxes need to be explored at even longer time scales, e.g., at decadal scales, to capture long-drawn-out trends associated with stand disturbance and its subsequent recovery.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"59 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evapotranspiration and its partitioning during and following a mountain pine beetle infestation of a lodgepole pine stand in the interior of British Columbia, Canada","authors":"Shaorong Hao, Xin Jia, Hongxian Zhao, Xinhao Li, Yanmei Mu, T. Zha, Peng Liu, C. Bourque","doi":"10.3389/ffgc.2024.1352853","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1352853","url":null,"abstract":"Massive tree mortality events in western Canada due to widespread infestation by mountain pine beetle (MPB) are expected to impact local-to-regional evapotranspiration (ET) dynamics during and after a disturbance. How ecosystem-level ET and its components may vary with canopy-tree mortality (treefall) and subsequent understory recovery remains unclear.We used 10 years of continuous eddy-covariance and remote-sensing data (2007–2016) and machine-learning models based on random forest and xgboost to determine forest- and climate-driven effects at temporal scales appropriate for a lodgepole pine-dominated stand following a major, five-year MPB disturbance initiated in the summer of 2006.Total annual ET over the 10 years ranged from 207.2 to 384.6 mm, with annual plant transpiration (T) contributing to 57 ± 5.4% (mean ± standard deviation) of annual ET. Annual ET initially declined (2007–2011) and then increased (2011–2016), with ET and T/ET increasing at statistically non-significant rates of approximately 3.2 and 1.2% per year from 2007 to 2016. Air temperature (Ta) and vapor pressure deficit (VPD) were the most important predictors of seasonal variation in ET and T/ET during the 10-year period, with high Ta, VPD, and photosynthetically active radiation (PAR) causing ET and T/ET to increase. Annual ET increased with both increasing spring Ta and decreasing VPD. Annual T/ET was shown to increase with increasing VPD and decrease with increasing volumetric soil water content at a 5-cm depth (VWC5). Enhanced vegetation index (EVI, an indicator of canopy greenness) lagged T and overstory tree mortality, whereas previous- and current-year values of EVI were shown to be poor predictors of annual ET and T/ET.These findings suggest that the promotion of climate factors on forest ecosystem-level water vapor fluxes may offset reductions promoted by MPB outbreaks. Climate processes affected water vapor fluxes more than biotic factors, like stand greenness, highlighting the need to include climate-regulatory mechanisms in predictive models of ET dynamics during and subsequent to stand disturbance. Climate and forest-greenness effects on water vapor fluxes need to be explored at even longer time scales, e.g., at decadal scales, to capture long-drawn-out trends associated with stand disturbance and its subsequent recovery.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"186 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139837514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial: Impacts of global change on protective forests in mountain areas","authors":"Alessandra Bottero, Christine Moos, Ana Stritih, Michaela Teich","doi":"10.3389/ffgc.2024.1375285","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1375285","url":null,"abstract":"","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"55 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial: Impacts of global change on protective forests in mountain areas","authors":"Alessandra Bottero, Christine Moos, Ana Stritih, Michaela Teich","doi":"10.3389/ffgc.2024.1375285","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1375285","url":null,"abstract":"","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"23 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139781869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salient features and ecosystem services of tree species in mountainous indigenous agroforestry systems of North-Eastern Tanzania","authors":"Oforo Didas Kimaro, Ellen Desie, D. Kimaro, K. Vancampenhout, K. Feger","doi":"10.3389/ffgc.2023.1082864","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1082864","url":null,"abstract":"Indigenous agroforestry systems in tropical mountainous environments provide crucial ecosystem services, but these ecosystems are also facing some challenges. A loss of diversity and native tree species in the overstory layer has been a growing concern in agroforestry worldwide, yet the drivers behind it remain inadequately understood. We hypothesize that the choice of overstory tree species is closely linked to the ecosystem services required by farmers, their livelihood strategy, and the salient features of each system. We, therefore, investigated four different farming systems in the mountains of northeastern Tanzania, i.e., the Kihamba on Mt. Kilimanjaro, Ginger agroforestry in the South Pare mountains, and Miraba and Mixed spices agroforestry in the West and East Usambara. In 82 farms, we collected data on the structure, tree species composition (both native and non-native), diversity, and associated provisioning ecosystem services as identified by smallholder farmers. Our results indicate that although all studied systems are multi-layered with three or four vertical layers, they have notable differences in their salient features concerning structure, composition, and diversity. The unique climate, landscape setting, soil, historical background, and economic opportunities that exist in each region contribute to those differences. Our findings indicate that the Kihamba system had the highest number of native tree species, and the largest diversity in species used for provisioning services, followed by Ginger agroforestry. No native species were used in Miraba or Mixed spices agroforestry, where a limited number of non-native tree species are planted mainly for fuel and timber or as a crop, respectively. Our findings regarding reported provisioning ES corroborate our hypothesis and imply that policies to increase resilience and restore the native tree species cover of the agroforestry systems of Tanzania can only be successful if knowledge of the ES potential of native species is increased, and interventions are tailored to each system’s ES needs for conservation as well as livelihood.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"44 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139780165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salient features and ecosystem services of tree species in mountainous indigenous agroforestry systems of North-Eastern Tanzania","authors":"Oforo Didas Kimaro, Ellen Desie, D. Kimaro, K. Vancampenhout, K. Feger","doi":"10.3389/ffgc.2023.1082864","DOIUrl":"https://doi.org/10.3389/ffgc.2023.1082864","url":null,"abstract":"Indigenous agroforestry systems in tropical mountainous environments provide crucial ecosystem services, but these ecosystems are also facing some challenges. A loss of diversity and native tree species in the overstory layer has been a growing concern in agroforestry worldwide, yet the drivers behind it remain inadequately understood. We hypothesize that the choice of overstory tree species is closely linked to the ecosystem services required by farmers, their livelihood strategy, and the salient features of each system. We, therefore, investigated four different farming systems in the mountains of northeastern Tanzania, i.e., the Kihamba on Mt. Kilimanjaro, Ginger agroforestry in the South Pare mountains, and Miraba and Mixed spices agroforestry in the West and East Usambara. In 82 farms, we collected data on the structure, tree species composition (both native and non-native), diversity, and associated provisioning ecosystem services as identified by smallholder farmers. Our results indicate that although all studied systems are multi-layered with three or four vertical layers, they have notable differences in their salient features concerning structure, composition, and diversity. The unique climate, landscape setting, soil, historical background, and economic opportunities that exist in each region contribute to those differences. Our findings indicate that the Kihamba system had the highest number of native tree species, and the largest diversity in species used for provisioning services, followed by Ginger agroforestry. No native species were used in Miraba or Mixed spices agroforestry, where a limited number of non-native tree species are planted mainly for fuel and timber or as a crop, respectively. Our findings regarding reported provisioning ES corroborate our hypothesis and imply that policies to increase resilience and restore the native tree species cover of the agroforestry systems of Tanzania can only be successful if knowledge of the ES potential of native species is increased, and interventions are tailored to each system’s ES needs for conservation as well as livelihood.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"231 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139839988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing data-driven soil moisture modeling with physically-guided LSTM networks","authors":"Qingtian Geng, Sen Yan, Qingliang Li, Cheng Zhang","doi":"10.3389/ffgc.2024.1353011","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1353011","url":null,"abstract":"In recent years, deep learning methods have shown significant potential in soil moisture modeling. However, a prominent limitation of deep learning approaches has been the absence of physical mechanisms. To address this challenge, this study introduces two novel loss functions designed around physical mechanisms to guide deep learning models in capturing physical information within the data. These two loss functions are crafted to leverage the monotonic relationships between surface water variables and shallow soil moisture as well as deep soil water. Based on these physically-guided loss functions, two physically-guided Long Short-Term Memory (LSTM) networks, denoted as PHY-LSTM and PHYs-LSTM, are proposed. These networks are trained on the global ERA5-Land dataset, and the results indicate a notable performance improvement over traditional LSTM models. When used for global soil moisture forecasting for the upcoming day, PHY-LSTM and PHYs-LSTM models exhibit closely comparable results. In comparison to conventional data-driven LSTM models, both models display a substantial enhancement in various evaluation metrics. Specifically, PHYs-LSTM exhibits improvements in several key performance indicators: an increase of 13.6% in Kling-Gupta Efficiency (KGE), a 20.7% increase in Coefficient of Determination (R2), an 8.2% reduction in Root Mean Square Error (RMSE), and a 4.4% increase in correlation coefficient (R). PHY-LSTM also demonstrates improvements, with a 14.8% increase in KGE, a 19.6% increase in R2, an 8.2% reduction in RMSE, and a 4.4% increase in R. Additionally, both models exhibit enhanced physical consistency over a wide geographical area. Experimental results strongly emphasize that the incorporation of physical mechanisms can significantly bolster the predictive capabilities of data-driven soil moisture models.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"26 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139851473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing data-driven soil moisture modeling with physically-guided LSTM networks","authors":"Qingtian Geng, Sen Yan, Qingliang Li, Cheng Zhang","doi":"10.3389/ffgc.2024.1353011","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1353011","url":null,"abstract":"In recent years, deep learning methods have shown significant potential in soil moisture modeling. However, a prominent limitation of deep learning approaches has been the absence of physical mechanisms. To address this challenge, this study introduces two novel loss functions designed around physical mechanisms to guide deep learning models in capturing physical information within the data. These two loss functions are crafted to leverage the monotonic relationships between surface water variables and shallow soil moisture as well as deep soil water. Based on these physically-guided loss functions, two physically-guided Long Short-Term Memory (LSTM) networks, denoted as PHY-LSTM and PHYs-LSTM, are proposed. These networks are trained on the global ERA5-Land dataset, and the results indicate a notable performance improvement over traditional LSTM models. When used for global soil moisture forecasting for the upcoming day, PHY-LSTM and PHYs-LSTM models exhibit closely comparable results. In comparison to conventional data-driven LSTM models, both models display a substantial enhancement in various evaluation metrics. Specifically, PHYs-LSTM exhibits improvements in several key performance indicators: an increase of 13.6% in Kling-Gupta Efficiency (KGE), a 20.7% increase in Coefficient of Determination (R2), an 8.2% reduction in Root Mean Square Error (RMSE), and a 4.4% increase in correlation coefficient (R). PHY-LSTM also demonstrates improvements, with a 14.8% increase in KGE, a 19.6% increase in R2, an 8.2% reduction in RMSE, and a 4.4% increase in R. Additionally, both models exhibit enhanced physical consistency over a wide geographical area. Experimental results strongly emphasize that the incorporation of physical mechanisms can significantly bolster the predictive capabilities of data-driven soil moisture models.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":" 33","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139791486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement effects of mangrove restoration on blue carbon storage in Qinzhou Bay","authors":"Wentao Song, Yukun Hou, Wenjuan Zhu, Yaocheng Fan, Haoyu Xu, Chengyu Cai, Guanghao Li, Lin Huang","doi":"10.3389/ffgc.2024.1328783","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1328783","url":null,"abstract":"Mangroves are the main carbon sinks in tropical regions and have high capabilities for carbon sequestration. Protection and restoration of mangroves are necessary to reduce carbon emissions and fight climate change. While the Qinzhou Bay as the main area of national mangrove restoration plan in the future, studies on its carbon pools, especially assessment of the carbon sink enhancement effect of restored mangroves along forest chronosequence, are lacking.This study aimed to quantify the changes in restored mangrove soil carbon stock, vegetation and root carbon stocks along the forest age sequence in Qinzhou Bay through field survey.The results revealed that the carbon stocks of vegetation and roots significantly increased with the developing forest age. Only in the soil layer above 30 cm, the soil carbon storage apparently increased with the developing forest age in non-cofferdam area, and then decreased slowly after reaching the peak (at 6 ~ 8 years). Moreover, the soil carbon storage of mangroves was greater in the cofferdam area than in the non-cofferdam area.This implied that the cofferdam restoration efforts may be more effective in enhancing blue carbon storage, during the initial stages of the restoration process. The results of this study suggested that mangrove restoration has substantial potential capacity in carbon storage and nutrient cycling, providing a reference for the protection and restoration efforts concerning mangroves.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139795588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement effects of mangrove restoration on blue carbon storage in Qinzhou Bay","authors":"Wentao Song, Yukun Hou, Wenjuan Zhu, Yaocheng Fan, Haoyu Xu, Chengyu Cai, Guanghao Li, Lin Huang","doi":"10.3389/ffgc.2024.1328783","DOIUrl":"https://doi.org/10.3389/ffgc.2024.1328783","url":null,"abstract":"Mangroves are the main carbon sinks in tropical regions and have high capabilities for carbon sequestration. Protection and restoration of mangroves are necessary to reduce carbon emissions and fight climate change. While the Qinzhou Bay as the main area of national mangrove restoration plan in the future, studies on its carbon pools, especially assessment of the carbon sink enhancement effect of restored mangroves along forest chronosequence, are lacking.This study aimed to quantify the changes in restored mangrove soil carbon stock, vegetation and root carbon stocks along the forest age sequence in Qinzhou Bay through field survey.The results revealed that the carbon stocks of vegetation and roots significantly increased with the developing forest age. Only in the soil layer above 30 cm, the soil carbon storage apparently increased with the developing forest age in non-cofferdam area, and then decreased slowly after reaching the peak (at 6 ~ 8 years). Moreover, the soil carbon storage of mangroves was greater in the cofferdam area than in the non-cofferdam area.This implied that the cofferdam restoration efforts may be more effective in enhancing blue carbon storage, during the initial stages of the restoration process. The results of this study suggested that mangrove restoration has substantial potential capacity in carbon storage and nutrient cycling, providing a reference for the protection and restoration efforts concerning mangroves.","PeriodicalId":507254,"journal":{"name":"Frontiers in Forests and Global Change","volume":"76 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139855464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}