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Lang W, Qian S, Chen X. Daylength predominates the bud growth initiation of winter deciduous forest trees in the monsoon region of China. FRONTIERS IN PLANT SCIENCE 2024; 14:1327509. [PMID: 38273945 PMCID: PMC10808619 DOI: 10.3389/fpls.2023.1327509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024]
Abstract
Climate warming has induced significant shifts in spring phenology over both temperate and boreal forests. The timing of bud growth resuming from dormancy is crucial for predicting spring phenology. However, the mechanisms by which environmental cues, other than chilling accumulation, initiate bud growth remains unclear. By constructing a revised process-based spring phenology model incorporating photoperiod and temperature triggers of bud growth, we simulated the first leaf unfolding and first flowering dates of four deciduous forest trees during 1981-2014 at 102 stations across China's monsoon regions. Then, we revealed spatial patterns of the two triggers. Moreover, we compared fitting precision and robustness of the revised model with three mainstream models. Results show that the revised models can effectively simulate all spring phenology time series. Growth initiation of foliar and floral buds was induced by photoperiod lengthening in 80.8% and 77.7% of time series, and by temperature increasing in remaining 19.2% and 22.3% of time series, respectively. The proportions of time series with photoperiod- and temperature-initiated bud growth significantly increase and decrease from northern to southern climatic zones, respectively. Chilling exposure controls the predominant bud growth triggers in different climate zones. Specifically, in regions with long and severe winters where chilling requirement is easily fulfilled, rising temperature in spring alleviates the cold constraint and initiate bud growth. Conversely, in regions with short and mild winters, prolonged daylength in spring compensates the lack of chilling exposure to initiate bud growth. These findings suggest that photoperiod may limit spring phenology response to temperature in low-latitudes. Overall, our model slightly outperforms other models in terms of efficiency, accuracy, and robustness in modeling leaf unfolding and flowering dates. Therefore, this study deepens our understanding of the mechanisms of spring phenology, and improves the predicting capability of spring phenology models in the face of ongoing global warming.
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Affiliation(s)
| | | | - Xiaoqiu Chen
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
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2
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Ma X, Zhu X, Xie Q, Jin J, Zhou Y, Luo Y, Liu Y, Tian J, Zhao Y. Monitoring nature's calendar from space: Emerging topics in land surface phenology and associated opportunities for science applications. GLOBAL CHANGE BIOLOGY 2022; 28:7186-7204. [PMID: 36114727 PMCID: PMC9827868 DOI: 10.1111/gcb.16436] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/09/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
Vegetation phenology has been viewed as the nature's calendar and an integrative indicator of plant-climate interactions. The correct representation of vegetation phenology is important for models to accurately simulate the exchange of carbon, water, and energy between the vegetated land surface and the atmosphere. Remote sensing has advanced the monitoring of vegetation phenology by providing spatially and temporally continuous data that together with conventional ground observations offers a unique contribution to our knowledge about the environmental impact on ecosystems as well as the ecological adaptations and feedback to global climate change. Land surface phenology (LSP) is defined as the use of satellites to monitor seasonal dynamics in vegetated land surfaces and to estimate phenological transition dates. LSP, as an interdisciplinary subject among remote sensing, ecology, and biometeorology, has undergone rapid development over the past few decades. Recent advances in sensor technologies, as well as data fusion techniques, have enabled novel phenology retrieval algorithms that refine phenology details at even higher spatiotemporal resolutions, providing new insights into ecosystem dynamics. As such, here we summarize the recent advances in LSP and the associated opportunities for science applications. We focus on the remaining challenges, promising techniques, and emerging topics that together we believe will truly form the very frontier of the global LSP research field.
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Affiliation(s)
- Xuanlong Ma
- College of Earth and Environmental Sciences, Lanzhou UniversityLanzhouChina
| | - Xiaolin Zhu
- Department of Land Surveying and Geo‐InformaticsThe Hong Kong Polytechnic UniversityHong KongChina
| | - Qiaoyun Xie
- School of Life Sciences, Faculty of ScienceUniversity of Technology SydneySydneyNew South WalesAustralia
| | - Jiaxin Jin
- College of Hydrology and Water Resources, Hohai UniversityNanjingChina
| | - Yuke Zhou
- Key Laboratory of Ecosystem Network Observation and ModellingInstitute of Geographic Sciences and Natural Resources Research, Chinese Academy of SciencesBeijingChina
| | - Yunpeng Luo
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- Department of Environmental System ScienceETH ZurichZurichSwitzerland
| | - Yuxia Liu
- School of Life Sciences, Faculty of ScienceUniversity of Technology SydneySydneyNew South WalesAustralia
- Geospatial Sciences Center of Excellence (GSCE)South Dakota State UniversityBrookingsSouth DakotaUSA
| | - Jiaqi Tian
- Department of Land Surveying and Geo‐InformaticsThe Hong Kong Polytechnic UniversityHong KongChina
- Department of GeographyNational University of SingaporeSingaporeSingapore
| | - Yuhe Zhao
- College of Earth and Environmental Sciences, Lanzhou UniversityLanzhouChina
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3
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Shahbaz M, Bengtson P, Mertes JR, Kulessa B, Kljun N. Spatial heterogeneity of soil carbon exchanges and their drivers in a boreal forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154876. [PMID: 35358518 DOI: 10.1016/j.scitotenv.2022.154876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/02/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Boreal forests have a large impact on the global greenhouse gas balance and their soils constitute an important carbon (C) reservoir. Mature boreal forests are typically a net CO2 sink, but there are also examples of boreal forests that are persistent CO2 sources. The reasons remain often unknown, presumably due to a lack of understanding of how biotic and abiotic drivers interact to determine the microbial respiration of soil organic matter (SOM). This study aimed at identifying the main drivers of microbial SOM respiration and CO2 and CH4 soil chamber-fluxes within dry and wet sampling areas at the mature boreal forest of Norunda, Sweden, a persistent net CO2 source. The spatial heterogeneity of the drivers was assessed with a geostatistical approach combined with stepwise multiple regression. We found that heterotrophic soil respiration increased with SOM content and nitrogen (N) availability, while the SOM reactivity, i.e., SOM specific respiration, was determined by soil moisture and N availability. The latter suggests that microbial activity was N rather than C limited and that microbial N mining might be driving old-SOM decomposition, which was observed through a positive correlation between soil respiration and its δ13C values. SOM specific heterotrophic respiration was lower in wet than in dry areas, while no such dependencies were found for chamber-based soil CO2 fluxes, implying that oxygen depletion resulted in lower SOM reactivity. The chamber-based soil CH4 flux differed significantly between the wet and dry areas. In the wet area, we observed net CH4 emission that was positively related to soil moisture and NH4+-N content. Taken together, our findings suggest that N availability has a strong regulatory effect on soil CO2 and CH4 emissions at Norunda, and that microbial decomposition of old-SOM to release bioavailable N might be partly responsible for the net CO2 emission at the site.
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Affiliation(s)
- Muhammad Shahbaz
- Centre for Environmental and Climate Science, Lund University, 223 62 Lund, Sweden.
| | - Per Bengtson
- Department of Biology, Microbial Ecology Group, Lund University, 223 62 Lund, Sweden
| | - Jordan R Mertes
- Centre for Environmental and Climate Science, Lund University, 223 62 Lund, Sweden
| | - Bernd Kulessa
- Department of Geography, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Natascha Kljun
- Centre for Environmental and Climate Science, Lund University, 223 62 Lund, Sweden
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Otu-Larbi F, Conte A, Fares S, Wild O, Ashworth K. Current and future impacts of drought and ozone stress on Northern Hemisphere forests. GLOBAL CHANGE BIOLOGY 2020; 26:6218-6234. [PMID: 32893912 DOI: 10.1111/gcb.15339] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/29/2020] [Indexed: 06/11/2023]
Abstract
Rising ozone (O3 ) concentrations, coupled with an increase in drought frequency due to climate change, pose a threat to plant growth and productivity which could negatively affect carbon sequestration capacity of Northern Hemisphere (NH) forests. Using long-term observations of O3 mixing ratios and soil water content (SWC), we implemented empirical drought and O3 stress parameterizations in a coupled stomatal conductance-photosynthesis model to assess their impacts on plant gas exchange at three FLUXNET sites: Castelporziano, Blodgett and Hyytiälä. Model performance was evaluated by comparing model estimates of gross primary productivity (GPP) and latent heat fluxes (LE) against present-day observations. CMIP5 GCM model output data were then used to investigate the potential impact of the two stressors on forests by the middle (2041-2050) and end (2091-2100) of the 21st century. We found drought stress was the more significant as it reduced model overestimation of GPP and LE by ~11%-25% compared to 1%-11% from O3 stress. However, the best model fit to observations at all the study sites was obtained with O3 and drought stress combined, such that the two stressors counteract the impact of each other. With the inclusion of drought and O3 stress, GPP at CPZ, BLO and HYY is projected to increase by 7%, 5% and 8%, respectively, by mid-century and by 14%, 11% and 14% by 2091-2100 as atmospheric CO2 increases. Estimates were up to 21% and 4% higher when drought and O3 stress were neglected respectively. Drought stress will have a substantial impact on plant gas exchange and productivity, off-setting and possibly negating CO2 fertilization gains in future, suggesting projected increases in the frequency and severity of droughts in the NH will play a significant role in forest productivity and carbon budgets in future.
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Affiliation(s)
| | - Adriano Conte
- Council for Agricultural Research and Economics (CREA) - Research Centre for Forestry and Wood, Rome, Italy
| | - Silvano Fares
- National Research Council (CNR) - Institute of BioEconomy (IBE), Rome, Italy
| | - Oliver Wild
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Kirsti Ashworth
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
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Xu H, Xiao J, Zhang Z, Ollinger SV, Hollinger DY, Pan Y, Wan J. Canopy photosynthetic capacity drives contrasting age dynamics of resource use efficiencies between mature temperate evergreen and deciduous forests. GLOBAL CHANGE BIOLOGY 2020; 26:6156-6167. [PMID: 33245613 DOI: 10.1111/gcb.15312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Forest resource use efficiencies (RUEs) can vary with tree age, but the nature of these trends and their underlying mechanisms are not well understood. Understanding the age dynamics of forest RUEs and their drivers is vital for assessing the trade-offs between forest functions and resource consumption, making rational management policy, and projecting ecosystem carbon dynamics. Here we used the FLUXNET2015 and AmeriFlux datasets and published literature to explore the age-dependent variability of forest light use efficiency (LUE) and inherent water use efficiency as well as their main regulatory variables in temperate regions. Our results showed that evergreen forest RUEs initially increased before reaching the mature stage (i.e., around 90 years old), and then gradually declined; in contrast, RUEs continuously increased with age for mature deciduous forests. Changing canopy photosynthetic capacity (Amax) was the primary cause of age-related changes in RUEs across temperate forest sites. More importantly, soil nitrogen (N) increased in mature deciduous forests through time but decreased in older evergreen forests. The age-dependent changes in soil N were closely linked with the age dynamics of Amax for mature temperate forests. Additionally, soil nutrient conditions played a greater role in deciduous forest RUEs than evergreen forest RUEs. This study highlights the importance of stand age and forest type on temperate forest RUEs over the long term.
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Affiliation(s)
- Hang Xu
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation & Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - Zhiqiang Zhang
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation & Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
| | - Scott V Ollinger
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | | | - Yude Pan
- USDA Forest Service, Northern Research Station, Durham, NH, USA
| | - Jiaming Wan
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation & Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
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6
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Chi J, Nilsson MB, Laudon H, Lindroth A, Wallerman J, Fransson JES, Kljun N, Lundmark T, Ottosson Löfvenius M, Peichl M. The Net Landscape Carbon Balance-Integrating terrestrial and aquatic carbon fluxes in a managed boreal forest landscape in Sweden. GLOBAL CHANGE BIOLOGY 2020; 26:2353-2367. [PMID: 31912589 DOI: 10.1111/gcb.14983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/21/2019] [Indexed: 06/10/2023]
Abstract
The boreal biome exchanges large amounts of carbon (C) and greenhouse gases (GHGs) with the atmosphere and thus significantly affects the global climate. A managed boreal landscape consists of various sinks and sources of carbon dioxide (CO2 ), methane (CH4 ), and dissolved organic and inorganic carbon (DOC and DIC) across forests, mires, lakes, and streams. Due to the spatial heterogeneity, large uncertainties exist regarding the net landscape carbon balance (NLCB). In this study, we compiled terrestrial and aquatic fluxes of CO2 , CH4 , DOC, DIC, and harvested C obtained from tall-tower eddy covariance measurements, stream monitoring, and remote sensing of biomass stocks for an entire boreal catchment (~68 km2 ) in Sweden to estimate the NLCB across the land-water-atmosphere continuum. Our results showed that this managed boreal forest landscape was a net C sink (NLCB = 39 g C m-2 year-1 ) with the landscape-atmosphere CO2 exchange being the dominant component, followed by the C export via harvest and streams. Accounting for the global warming potential of CH4 , the landscape was a GHG sink of 237 g CO2 -eq m-2 year-1 , thus providing a climate-cooling effect. The CH4 flux contribution to the annual GHG budget increased from 0.6% during spring to 3.2% during winter. The aquatic C loss was most significant during spring contributing 8% to the annual NLCB. We further found that abiotic controls (e.g., air temperature and incoming radiation) regulated the temporal variability of the NLCB whereas land cover types (e.g., mire vs. forest) and management practices (e.g., clear-cutting) determined their spatial variability. Our study advocates the need for integrating terrestrial and aquatic fluxes at the landscape scale based on tall-tower eddy covariance measurements combined with biomass stock and stream monitoring to develop a holistic understanding of the NLCB of managed boreal forest landscapes and to better evaluate their potential for mitigating climate change.
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Affiliation(s)
- Jinshu Chi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Hjalmar Laudon
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Anders Lindroth
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Jörgen Wallerman
- Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Johan E S Fransson
- Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Natascha Kljun
- Centre for Environmental and Climate Research, Lund University, Lund, Sweden
| | - Tomas Lundmark
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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7
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Liu P, Black TA, Jassal RS, Zha T, Nesic Z, Barr AG, Helgason WD, Jia X, Tian Y, Stephens JJ, Ma J. Divergent long-term trends and interannual variation in ecosystem resource use efficiencies of a southern boreal old black spruce forest 1999-2017. GLOBAL CHANGE BIOLOGY 2019; 25:3056-3069. [PMID: 31055880 DOI: 10.1111/gcb.14674] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 05/14/2023]
Abstract
Long-term trends in ecosystem resource use efficiencies (RUEs) and their controlling factors are key pieces of information for understanding how an ecosystem responds to climate change. We used continuous eddy covariance and microclimate data over the period 1999-2017 from a 120-year-old black spruce stand in central Saskatchewan, Canada, to assess interannual variability, long-term trends, and key controlling factors of gross ecosystem production (GEP) and the RUEs of carbon (CUE = net primary production [NPP]/GEP), light (LUE = GEP/absorbed photosynthetic radiation [APAR]), and water (WUE = GEP/evapotranspiration [E]). At this site, annual GEP has shown an increasing trend over the 19 years (p < 0.01), which may be attributed to rising atmospheric CO2 concentration. Interannual variability in GEP, aside from its increasing trend, was most strongly related to spring temperatures. Associated with the significant increase in annual GEP were relatively small changes in NPP, APAR, and E, so that annual CUE showed a decreasing trend and annual LUE and WUE showed increasing trends over the 19 years. The long-term trends in the RUEs were related to the increasing CO2 concentration. Further analysis of detrended RUEs showed that their interannual variation was impacted most strongly by air temperature. Two-factor linear models combining CO2 concentration and air temperature performed well (R2 ~0.60) in simulating annual RUEs. LUE and WUE were positively correlated both annually and seasonally, while LUE and CUE were mostly negatively correlated. Our results showed divergent long-term trends among CUE, LUE, and WUE and highlighted the need to account for the combined effects of climatic controls and the 'CO2 fertilization effect' on long-term variations in RUEs. Since most RUE-based models rely primarily on one resource limitation, the observed patterns of relative change among the three RUEs may have important implications for RUE-based modeling of C fluxes.
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Affiliation(s)
- Peng Liu
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - T Andrew Black
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Rachhpal S Jassal
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Tianshan Zha
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Zoran Nesic
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Alan G Barr
- Climate Research Division, Environment and Climate Change Canada, Saskatoon, SK, Canada
- Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, Canada
| | - Warren D Helgason
- Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, SK, Canada
| | - Xin Jia
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Yun Tian
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Jilmarie J Stephens
- Biometeorology and Soil Physics Group, University of British Columbia, Vancouver, BC, Canada
| | - Jingyong Ma
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
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8
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Spatiotemporal Simulation of Net Ecosystem Productivity and Its Response to Climate Change in Subtropical Forests. FORESTS 2019. [DOI: 10.3390/f10080708] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Subtropical forests have great potential as carbon sinks; however, the relationship between net ecosystem productivity (NEP) and climate change is still unclear. This study took Zhejiang Province, a subtropical region, as an example. Based on remote sensing classification data of forest resources, the integrated terrestrial ecosystem carbon cycle (InTEC) model was used to simulate the spatiotemporal dynamics of the forest NEP in Zhejiang Province during 1985–2015 and analyze its response to meteorological factors such as temperature, precipitation, relative humidity, and radiation. Three patterns emerged: (1) The optimized InTEC model can better simulate the forest NEP in Zhejiang Province, and the correlation coefficient between the simulated NEP and observed NEP was up to 0.75. (2) From 1985 to 2015, the increase in the total NEP was rapid, with an average annual growth rate of 1.52 Tg·C·yr−1. During 1985–1988, the forests in Zhejiang Province were carbon sources. After 1988, the forests turned into carbon sinks and this continued to increase. During 2000–2015, more than 97% of the forests in Zhejiang Province were carbon sinks. The total NEP reached 32.02 Tg·C·yr−1, and the annual mean NEP increased to 441.91 gC·m−2·yr−1. The carbon sequestration capacity of forests in the east and southwest of Zhejiang Province is higher than that in the northeast of Zhejiang Province. (3) From 2000 to 2015, there was an extremely significant correlation between forest NEP and precipitation, with a correlation coefficient of 0.85. Simultaneously, the forest NEP showed a negative correlation with temperature and radiation, with a correlation coefficient of −0.56 for both, and the forest NEP was slightly negatively correlated with relative humidity. The relative contribution rates of temperature, precipitation, relative humidity, and radiation data to NEP showed that the contribution of precipitation to NEP is the largest, reaching 61%, followed by temperature and radiation at 18% and 17%, respectively. The relative contribution rate of relative humidity is the smallest at only 4%. During the period of 1985–1999, due to significant man-made disturbances, the NEP had a weak correlation with temperature, precipitation, relative humidity, and radiation. The results of this study are important for addressing climate change and illustrating the response mechanism between subtropical forest NEP and climate change.
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Zhang J, Liu M, Zhang M, Yang J, Cao R, Malhi SS. Changes of vegetation carbon sequestration in the tableland of Loess Plateau and its influencing factors. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:22160-22172. [PMID: 31147999 DOI: 10.1007/s11356-019-05561-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
The variations of vegetation carbon sequestration have become a gauge for evaluating the ecological effect of vegetation restoration. In this study, the spatiotemporal patterns of the net ecosystem production (NEP) were simulated using an improved CASA model and GSMSR model. It showed that the NEP markedly increased in the tableland of Loess Plateau during 2003-2012, with an annual average growth of 3.65 g C·m-2 a-1. The mixed broadleaf-conifer forest ranked first (127.23 g C·m-2 a-1) while the bare land and sparse vegetation presented the lowest carbon sequestration (14.64 g C·m-2 a-1). The NEP manifested a significantly uneven overall spatial distribution: high in the southwest and low in the northeast. The spatial variations of NEP resulted from the combined effects of geographic position, terrain, meteorology, and soil and vegetation, respectively. Quantitative isolation revealed that the most dominant factor of vegetation carbon sequestration was soil and vegetation, while terrain exerted insignificant impacts on the NEP.
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Affiliation(s)
- Jie Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi Province, China
| | - Mengyun Liu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi Province, China.
| | - Mengmeng Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi Province, China
| | - Jinghan Yang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi Province, China
| | - Runshan Cao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi Province, China
| | - Sukhdev S Malhi
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
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10
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Dolschak K, Gartner K, Berger TW. The impact of rising temperatures on water balance and phenology of European beech ( Fagus sylvatica L.) stands. ACTA ACUST UNITED AC 2019; 5:1347-1363. [PMID: 31656852 PMCID: PMC6814441 DOI: 10.1007/s40808-019-00602-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this article, we outline the set-up and the application of an eco-hydrological box model, with the aim to describe the water balance of deciduous (Fagus Sylvatica L.) forest stands. The water balance model (WBM) uses standard meteorological parameters as input variables and runs on a daily time step. It consists of two modules. The aboveground module (1) comprises routines for fog precipitation generation, precipitation interception and snowfall/snowmelt dynamics. Covered belowground processes (2) are bypass flow, percolation, soil evaporation and transpiration, where the latter two processes are considered separately. Preceding to the WBM, a routine is introduced, specifying the intra-annual foliage dynamics of beech. Emphasis is also laid on the inter-annual variation of beech phenology. Leaf sprouting and leaf senescence are calculated as functions of day-length and air temperature. The WBM was applied to four European beech dominated forest stands in the northeastern part of Austria. They are located on a gradient of declining annual precipitation (from west to east). The two easterly sites are located close to the (dry) limit of the natural distribution of beech. Records of soil moisture were used for the adjustment of 26 parameters. On all sites the calibration process (simulated annealing) delivered good predictions of soil moisture (Nash–Sutcliffe efficiency≥ 0.925). Then, the obtained parameterization was used to apply different scenarios of global warming. The temperature was increased step-wisely up to 4 °C. All scenarios were run (1) with present phenological conditions and (2) with phenology responding to higher temperatures. This way, we wanted to assign the effect of higher temperatures and longer growing seasons on the water dynamics of the forest stands. A warming of 1 °C corresponded roughly to an elongation of the growing season of 4.5 days, where the start of the growing season was affected more strongly than the end. Apparently, higher temperatures led to drier soils. The strongest change was observed in early summer, also amplified by an earlier start of the growing season. Rising temperatures led to lower export fluxes of liquid water, simultaneously increasing evapotranspiration (ET). The gain in ET was almost entirely assignable to increased soil evaporation. Drier soils led to a sharp depression of transpiration during summer months. This decline was compensated by the effect of elongated growing seasons. The risk of severe drought was increased by higher temperatures, but here the contribution of growing season length was negligible. Drier soils seem to hamper the stands’ productivity. For all warming scenarios, the estimated increase of the gross primary production, caused by longer periods of assimilation, is nullified by the effect of soil water deficit in mid-summer.
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Affiliation(s)
- Klaus Dolschak
- Department of Forest- and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences (BOKU), Peter Jordan-Straße 82, 1190 Vienna, Austria
| | - Karl Gartner
- Department of Forest Ecology and Soil, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Torsten W Berger
- Department of Forest- and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences (BOKU), Peter Jordan-Straße 82, 1190 Vienna, Austria
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Helbig M, Chasmer LE, Desai AR, Kljun N, Quinton WL, Sonnentag O. Direct and indirect climate change effects on carbon dioxide fluxes in a thawing boreal forest-wetland landscape. GLOBAL CHANGE BIOLOGY 2017; 23:3231-3248. [PMID: 28132402 DOI: 10.1111/gcb.13638] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 12/26/2016] [Indexed: 06/06/2023]
Abstract
In the sporadic permafrost zone of northwestern Canada, boreal forest carbon dioxide (CO2 ) fluxes will be altered directly by climate change through changing meteorological forcing and indirectly through changes in landscape functioning associated with thaw-induced collapse-scar bog ('wetland') expansion. However, their combined effect on landscape-scale net ecosystem CO2 exchange (NEELAND ), resulting from changing gross primary productivity (GPP) and ecosystem respiration (ER), remains unknown. Here, we quantify indirect land cover change impacts on NEELAND and direct climate change impacts on modeled temperature- and light-limited NEELAND of a boreal forest-wetland landscape. Using nested eddy covariance flux towers, we find both GPP and ER to be larger at the landscape compared to the wetland level. However, annual NEELAND (-20 g C m-2 ) and wetland NEE (-24 g C m-2 ) were similar, suggesting negligible wetland expansion effects on NEELAND . In contrast, we find non-negligible direct climate change impacts when modeling NEELAND using projected air temperature and incoming shortwave radiation. At the end of the 21st century, modeled GPP mainly increases in spring and fall due to reduced temperature limitation, but becomes more frequently light-limited in fall. In a warmer climate, ER increases year-round in the absence of moisture stress resulting in net CO2 uptake increases in the shoulder seasons and decreases during the summer. Annually, landscape net CO2 uptake is projected to decline by 25 ± 14 g C m-2 for a moderate and 103 ± 38 g C m-2 for a high warming scenario, potentially reversing recently observed positive net CO2 uptake trends across the boreal biome. Thus, even without moisture stress, net CO2 uptake of boreal forest-wetland landscapes may decline, and ultimately, these landscapes may turn into net CO2 sources under continued anthropogenic CO2 emissions. We conclude that NEELAND changes are more likely to be driven by direct climate change rather than by indirect land cover change impacts.
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Affiliation(s)
- Manuel Helbig
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Ankur R Desai
- Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Natascha Kljun
- Department of Geography, Swansea University, Singleton Park, Swansea, SA28PP, UK
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Oliver Sonnentag
- Département de géographie & Centre d'études nordiques, Université de Montréal, 520 Chemin de la Côte Sainte-Catherine, Montréal, QC, H2V 2B8, Canada
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Oelbermann M, Schiff SL. Inundating contrasting boreal forest soils: CO2 and CH4 production rates. ECOSCIENCE 2015. [DOI: 10.2980/17-2-3245] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Chen X, An S, Inouye DW, Schwartz MD. Temperature and snowfall trigger alpine vegetation green-up on the world's roof. GLOBAL CHANGE BIOLOGY 2015; 21:3635-3646. [PMID: 25906987 DOI: 10.1111/gcb.12954] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/09/2015] [Indexed: 06/04/2023]
Abstract
Rapid temperature increase and its impacts on alpine ecosystems in the Qinghai-Tibetan Plateau, the world's highest and largest plateau, are a matter of global concern. Satellite observations have revealed distinctly different trend changes and contradicting temperature responses of vegetation green-up dates, leading to broad debate about the Plateau's spring phenology and its climatic attribution. Large uncertainties in remote-sensing estimates of phenology significantly limit efforts to predict the impacts of climate change on vegetation growth and carbon balance in the Qinghai-Tibetan Plateau, which are further exacerbated by a lack of detailed ground observation calibration. Here, we revealed the spatiotemporal variations and climate drivers of ground-based herbaceous plant green-up dates using 72 green-up datasets for 22 herbaceous plant species at 23 phenological stations, and corresponding daily mean air temperature and daily precipitation data from 19 climate stations across eastern and southern parts of the Qinghai-Tibetan Plateau from 1981 to 2011. Results show that neither the continuously advancing trend from 1982 to 2011, nor a turning point in the mid to late 1990s as reported by remote-sensing studies can be verified by most of the green-up time series, and no robust evidence for a warmer winter-induced later green-up dates can be detected. Thus, chilling requirements may not be an important driver influencing green-up responses to spring warming. Moreover, temperature-only control of green-up dates appears mainly at stations with relatively scarce preseason snowfall and lower elevation, while coupled temperature and precipitation controls of green-up dates occur mostly at stations with relatively abundant preseason snowfall and higher elevation. The diversified interactions between snowfall and temperature during late winter to early spring likely determine the spatiotemporal variations of green-up dates. Therefore, prediction of vegetation growth and carbon balance responses to global climate change on the world's roof should integrate both temperature and snowfall variations.
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Affiliation(s)
- Xiaoqiu Chen
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, P.R. China
| | - Shuai An
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, P.R. China
| | - David W Inouye
- Department of Biology, University of Maryland, College Park, MD, 20742-4415, USA
| | - Mark D Schwartz
- Department of Geography, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413, USA
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Barman R, Jain AK, Liang M. Climate-driven uncertainties in modeling terrestrial gross primary production: a site level to global-scale analysis. GLOBAL CHANGE BIOLOGY 2014; 20:1394-1411. [PMID: 24273031 DOI: 10.1111/gcb.12474] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 09/05/2013] [Accepted: 09/08/2013] [Indexed: 06/02/2023]
Abstract
We used a land surface model to quantify the causes and extents of biases in terrestrial gross primary production (GPP) due to the use of meteorological reanalysis datasets. We first calibrated the model using meteorology and eddy covariance data from 25 flux tower sites ranging from the tropics to the northern high latitudes and subsequently repeated the site simulations using two reanalysis datasets: NCEP/NCAR and CRUNCEP. The results show that at most sites, the reanalysis-driven GPP bias was significantly positive with respect to the observed meteorology-driven simulations. Notably, the absolute GPP bias was highest at the tropical evergreen tree sites, averaging up to ca. 0.45 kg C m(-2) yr(-1) across sites (ca. 15% of site level GPP). At the northern mid-/high-latitude broadleaf deciduous and the needleleaf evergreen tree sites, the corresponding annual GPP biases were up to 20%. For the nontree sites, average annual biases of up to ca. 20-30% were simulated within savanna, grassland, and shrubland vegetation types. At the tree sites, the biases in short-wave radiation and humidity strongly influenced the GPP biases, while the nontree sites were more affected by biases in factors controlling water stress (precipitation, humidity, and air temperature). In this study, we also discuss the influence of seasonal patterns of meteorological biases on GPP. Finally, using model simulations for the global land surface, we discuss the potential impacts of site-level reanalysis-driven biases on the global estimates of GPP. In a broader context, our results can have important consequences on other terrestrial ecosystem fluxes (e.g., net primary production, net ecosystem production, energy/water fluxes) and reservoirs (e.g., soil carbon stocks). In a complementary study (Barman et al., ), we extend the present analysis for latent and sensible heat fluxes, thus consistently integrating the analysis of climate-driven uncertainties in carbon, energy, and water fluxes using a single modeling framework.
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Affiliation(s)
- Rahul Barman
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Ueyama M, Iwata H, Harazono Y. Autumn warming reduces the CO2 sink of a black spruce forest in interior Alaska based on a nine-year eddy covariance measurement. GLOBAL CHANGE BIOLOGY 2014; 20:1161-1173. [PMID: 24132878 DOI: 10.1111/gcb.12434] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/14/2013] [Indexed: 06/02/2023]
Abstract
Nine years (2003-2011) of carbon dioxide (CO2) flux were measured at a black spruce forest in interior Alaska using the eddy covariance method. Seasonal and interannual variations in the gross primary productivity (GPP) and ecosystem respiration (RE) were associated primarily with air temperature: warmer conditions enhanced GPP and RE. Meanwhile, interannual variation in annual CO2 balance was controlled predominantly by RE, and not GPP. During these 9 years of measurement, the annual CO2 balance shifted from a CO2 sink to a CO2 source, with a 9-year average near zero. The increase in autumn RE was associated with autumn warming and was mostly attributed to a shift in the annual CO2 balance. The increase in autumn air temperature (0.22 °C yr(-1)) during the 9 years of study was 15 times greater than the long-term warming trend between 1905 and 2011 (0.015 °C yr(-1)) due to decadal climate oscillation. This result indicates that most of the shifts in observed CO2 fluxes were associated with decadal climate variability. Because the natural climate varies in a cycle of 10-30 years, a long-term study covering at least one full cycle of decadal climate oscillation is important to quantify the CO2 balance and its interaction with the climate.
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Affiliation(s)
- Masahito Ueyama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan; International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, USA
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Grossiord C, Granier A, Gessler A, Jucker T, Bonal D. Does Drought Influence the Relationship Between Biodiversity and Ecosystem Functioning in Boreal Forests? Ecosystems 2013. [DOI: 10.1007/s10021-013-9729-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Assessing Performance of NDVI and NDVI3g in Monitoring Leaf Unfolding Dates of the Deciduous Broadleaf Forest in Northern China. REMOTE SENSING 2013. [DOI: 10.3390/rs5020845] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Bracho R, Starr G, Gholz HL, Martin TA, Cropper WP, Loescher HW. Controls on carbon dynamics by ecosystem structure and climate for southeastern U.S. slash pine plantations. ECOL MONOGR 2012. [DOI: 10.1890/11-0587.1] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mo X, Chen JM, Ju W, Black TA. Optimization of ecosystem model parameters through assimilating eddy covariance flux data with an ensemble Kalman filter. Ecol Modell 2008. [DOI: 10.1016/j.ecolmodel.2008.06.021] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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