title: [Net carbon exchange and its environmental affecting factors in a forest plantation in Badaling, Beijing of China].
abstract: By using eddy covariance technique, a year-round (November, 2011-October, 2012) continuous measurement of net ecosystem carbon dioxide exchange (NEE) was conducted in a 4-year old mixed forest plantation in Badaling of Beijing. The forest plantation ecosystem was a net carbon sink in July and August, but a carbon source in the rest months. The monthly net carbon loss and uptake were the largest in April and July, respectively. The annual net ecosystem productivity was (-256 +/- 21) g C x m(-2) x a(-1), in which, the ecosystem respiration was (950 +/- 36) g C x m(-2) x a(-1), and the gross ecosystem productivity was (694 +/- 17) g C x m(-2) x a(-1). The nighttime NEE increased exponentially with the soil temperature at 10 cm depth, with the estimated temperature sensitivity of ecosystem respiration (Q10 ) being 2.2. During the growth season (May-September), the daytime NEE increased with photosynthetically active radiation (PAR) as described by the Michaelis-Menten rectangular hyperbola. The ecosystem quantum yield varied seasonally, ranging from 0.0219 micromol CO2 x micromol(-1) in May to 0.0506 micromol CO2 x micromol(-1) in July. The maximum carbon assimilation rate and the average daytime respiration followed the seasonal trends of PAR and air temperature. In July and August, vapor pressure deficit and soil moisture played a significant role in determining daytime NEE.
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China. t779663873@126.com
authors.forename: Xiang
authors.initials: X
authors.lastname: Tang
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Chen
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
authors.forename: Chun-Yi
authors.initials: CY
authors.lastname: Li
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
authors.forename: Tian-Shan
authors.initials: TS
authors.lastname: Zha
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.affiliation: Beijing Forestry Carbon Administration (BFCA), Beijing 100013, China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Wang
authors.affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Jia
mesh_terms: D002244:Carbon / Q000378:metabolism*; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism; D002681:China; D065928:Forests; D010788:Photosynthesis; D012621:Seasons; D014197:Trees / Q000254:growth & development / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D002244:Carbon