Eff ects of environmental factors on the temporal and spatial variations in branch and leaf CO_(2)effl ux of Larix gmelinii var.principis-rupprechtii Mayr  

作　　者：Longjie Li Xiangzhen Wang Zhongkui Jia 

机构地区：[1]Key Laboratory for Silviculture and Conservation of the Ministry of Education,College of Forestry,Beijing Forestry University,Beijing 100083,People’s Republic of China

出　　处：《Journal of Forestry Research》2023年第4期1007-1019,共13页林业研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.31870387),China Scholarship Council.

摘　　要：The CO_(2)effl ux of branches and leaves plays an important role in ecosystem carbon balance.Using a carbon fl ux system,the effl ux of Larix gmelinii var.principisrupprechtii(Dahurian larch)was investigated in 27 years(immature),31 years(near-mature),and 47 years(mature)stands at diurnal,seasonal,and spatial scales(direction and height)as well as its connection with environmental factors from May to October 2020.Diurnal variation in effl ux was a single peak,and the maximum occurring between 14:00 and 16:00.Seasonal variation also exhibited a single peak,with the maximum in late July and the minimum in early October.From May to September,effl ux on the south side was the largest among the three stands,and mean values on the south side of 27 year-old,31 year-old,and 47 year-old trees were 0.50,0.97 and 1.05μmol·m^(–2)·s^(–1),respectively.The minimum occurred on the north side.Except for the maximum in July and September in the 27 year-old stand in the middle of the canopy,the maximum effl ux in the upper canopy,and the means in the 27 year-old,31 year-old,and 47 year-old stands were 0.49,0.96 and 1.04μmol·m^(-2)·s^(-1),respectively;the minimum occurred in the lower canopy.Temperatures and relative humidity infl uenced seasonal variations in effl ux.Seasonal variation in temperature sensitivity coeffi cient(Q 10)was opposite that of temperature,increasing with decreasing temperature.At the spatial scale,maximum Q 10 occurred in the mid canopy.With the effl ux and temperature data in diff erent locations,it is possible to better estimate effl ux variations in each stand.

关 键 词：CO_(2)effl ux Temperature sensitivity coeffi cient(Q 10) Temporal and spatial variations Environmental factors 

分 类 号：S791.222[农业科学—林木遗传育种]