title: Light use efficiency of a warm-temperate mixed plantation in north China.
abstract: Light use efficiency (LUE) is one of the important parameters on calculating terrestrial gross primary productivity (GPP) and net primary productivity (NPP). Based on 5-year (2006-2010) carbon flux and climatic variable data of a mixed plantation in north China, the seasonal and interannual variation of LUE was investigated and the biophysical controls were examined. Our results show that LUE had a distinct seasonal course, and peaked in the vigorous growing season with a value of 0.92-1.27 g C MJ-1. During the period of 2006-2010, annual mean LUE ranged between 0.54 and 0.62 g C MJ-1, and it was linearly correlated with annual GPP. In the growing season, LUE was significantly linked with the water availability variables (including monthly mean vapor pressure deficit (VPD), precipitation, evaporative fraction (EF), and the ratio of precipitation to evapotranspiration (P/ET)) and canopy conductance (gc). However, EF was a better estimator of LUE compared with other biophysical variables. LUE decreased with an increase of the clearness index (CI), indicating that LUE was higher under cloudy sky conditions than that under sunny sky conditions in the mixed plantation.
authors.affiliation: College of Forestry, Beijing Forestry University, Beijing, 100083, China. tongxj@bjfu.edu.cn.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Tong
authors.affiliation: Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Meng
authors.affiliation: Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zheng
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D002681:China; D019684:Magnoliopsida / Q000502:physiology; D010788:Photosynthesis; D018526:Plant Transpiration; D012621:Seasons; D013472:Sunlight; D013696:Temperature; D014197:Trees / Q000502:physiology
chemical_list: D002245:Carbon Dioxide
keywords: Clearness index; Gross primary productivity; Light use efficiency; Mixed plantation