文献类型：期刊文献

英文题名：Effects of Biophysical Factors on Light Use Efficiency at Multiple Time Scales in a Chinese Cork Oak Plantation Ecosystem

作者：Gao, Xiang[1,2,3] Zhang, Jinsong[1,2,3] Cai, Jinfeng[3] Meng, Ping[1,2,3] Huang, Hui[1,2,3] Sun, Shoujia[1,2,3]

第一作者：高翔;Gao, Xiang

通信作者：Zhang, JS[1];Zhang, JS[2];Zhang, JS[3]

机构：[1]Chinese Acad Forestry, Key Lab Tree Breeding & Cultivat, Natl Forestry & Grassland Adm, Res Inst Forestry, Beijing 100091, Peoples R China;[2]Henan Xiaolangdi Forest Ecosyst Natl Observat & Re, Jiyuan 454650, Peoples R China;[3]Nanjing Forestry Univ, Collaborat Innovat Ctr Sustainable Forestry Southe, Nanjing 210037, Peoples R China

年份：2024

卷号：15

期号：9

外文期刊名：FORESTS

收录：;EI(收录号：20244017123276);Scopus(收录号：2-s2.0-85205046091);WOS:【SCI-EXPANDED(收录号:WOS:001323437600001)】；

基金：This research was funded by National Nonprofit Institute Research Grant of the Chinese Academy of Forestry (CAFYBB2022SY001) and National Natural Science Foundation of China (32301662).

语种：英文

外文关键词：light use efficiency; temporal variation; biophysical control; Chinese cork oak plantation

摘要：Light use efficiency (LUE) characterizes the efficiency of vegetation in converting photosynthetically active radiation (PAR) into biomass energy through photosynthesis and is a critical parameter for gross primary productivity (GPP) in terrestrial ecosystems. Based on the eddy covariance measurements of a Chinese cork oak plantation ecosystem in northern China, the temporal variations in LUE were investigated, and biophysical factors were examined at time scales ranging from hours to years. Our results show that diurnal LUE first increased sharply before 8:30 and then decreased gradually until 12:00, thereafter increasing gradually and reaching the maximum value at sunset during the growing season. The daily and monthly LUE first increased and then decreased within a year and showed a substantial drop around June. The annual LUE ranged from 0.09 to 0.17 g C mol photon-1, and the multiyear mean maximal LUE was 0.30 g C mol photon-1 during 2006-2019. Only GPP (positive) and clearness index (CI) (negative) had consistent effects on LUE at different time scales, and the effects of the remaining biophysical factors on LUE were different as the time scale changed. The effects of air temperature, vapor pressure deficit, precipitation, evaporative fraction, and normalized difference vegetation index on LUE were mainly indirect (via PAR and/or GPP). When CI decreased, an increased ratio of diffuse PAR to PAR produced a more uniform irradiance in the canopy, which ultimately resulted in a higher LUE. Due to climate change in our study area, the annual LUE may decrease in the future but improving management practices may slow or even reverse this trend in the annual LUE in the studied Chinese cork oak plantation.