Decline in tree-ring growth of Picea mongolica and its intra-annual eco-physiological responses to drought and CO_(2) enrichment in semi-arid China  

作　　者：Xiaomin Zeng Ping Ni Xiaohong Liu Wenzhi Wang Yao Li Wenchao Wang 

机构地区：[1]School of Geography and Tourism,Shaanxi Normal University,Xi’an 710119,People’s Republic of China [2]The Key Laboratory of Mountain Environment Evolution and Regulation,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,People’s Republic of China [3]CAS Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,People’s Republic of China [4]University of Chinese Academy of Sciences,Beijing 100049,People’s Republic of China

出　　处：《Journal of Forestry Research》2024年第4期89-101,共13页林业研究（英文版）

基　　金：This study was supported by the National Natural Science Foundation of China(42277448,41971104 and 41807431);the National Science Foundation of Shaanxi Province(2019JQ-325);the Fundamental Research Funds for the Central Universities(GK201903068 and GK202206032).

摘　　要：Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains unre-solved.In this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent droughts.The results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since 1960.How-ever,the decreasing trend of earlywood BAI_(res) was higher than that of latewood.Climate response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,respectively.BAI_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly affected.Decreasing stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing season.Our study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.

关 键 词：Tree growth DROUGHT Water-use efficiency Seasonal differences Stable isotopes 

分 类 号：S791.18[农业科学—林木遗传育种]