Effects of thinning and understory removal on water use efficiency of Pinus massoniana:evidence from photosynthetic capacity and stable carbon isotope analyses

作     者：Ting Wang Qing Xu Beibei Zhang Deqiang Gao Ying Zhang Jing Jiang Haijun Zuo Ting Wang;Qing Xu;Beibei Zhang;Deqiang Gao;Ying Zhang;Jing Jiang;Haijun Zuo;Yanbo Hu

作者机构：Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationEcology and Nature Conservation InstituteChinese Academy of ForestryBeijing 100091People’s Republic of China College of Agronomy and Agricultural EngineeringLiaocheng UniversityLiaocheng 252000People’s Republic of China Department of Forest and Conservation SciencesFaculty of ForestryUniversity of British ColumbiaVancouverBC V6T 1Z4Canada 

出 版 物：《Journal of Forestry Research》 (林业研究（英文版）)

年 卷 期：2024年第35卷第2期

页      面：42-53页

核心收录：

学科分类：0710[理学-生物学] 0907[农学-林学] 08[工学] 0818[工学-地质资源与地质工程] 0829[工学-林业工程] 09[农学] 0903[农学-农业资源与环境] 0815[工学-水利工程] 0901[农学-作物学] 0714[理学-统计学（可授理学、经济学学位）] 0701[理学-数学] 

基　　金：supported by the National Key Research and Development Program of China(2016YFD0600201) the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003) the National Natural Science Foundation of China(31870716 31670720) 

主　　题：Stable carbon isotope Water use efficiency Thinning Understory removal Photosynthetic capacity Needle water potential 

摘      要：Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate ***,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management *** this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of *** capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were ***,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water *** removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water *** general,thinning may be an appropriate management measure to promote *** WUE to cope with seasonal droughts under future extreme climates.