title: Water-use efficiency of an old-growth forest in lower subtropical China.
abstract: Carbon and water fluxes are key properties of ecosystem processes and functions. A better understanding of their temporal dynamics and coupling mechanism between these fluxes will help us improve ecosystem management for mitigation as well as adaption to future climatic change. From 2003 to 2009, carbon and water flux data were obtained by the eddy covariance method over an old-growth forest in the lower subtropical China. The 7 years of observational data indicated that the water-use efficiency (WUE) of the old-growth forest exhibited weak inter-annual variability. The mean annual WUE ranged from 1.70 to 1.98 g C kg-1H2O. An analysis of the effects of environmental variables on the monthly gross primary productivity (GPP) and evapotranspiration (ET) indicated that solar radiation, air temperature, precipitation and vapor pressure deficit (VPD) produced similar effects on the monthly GPP and ET, which suggests that photosynthesis and ET were similarly driven by the climatic variables. At the monthly scale, the WUE decreased significantly as the precipitation and soil moisture content increased. However, a significant correlation was not detected between the WUE and the VPD at the monthly scale. Moisture conditions tend to be major drivers of the ecosystem WUE.
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Xiuzhi
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Fengling
authors.initials: F
authors.lastname: Long
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Qianmei
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Jiyue
authors.initials: J
authors.lastname: Li
mesh_terms: D018533:Biomass; D057486:Carbon Cycle; D002681:China; D065928:Forests; D006813:Humidity; D019684:Magnoliopsida / Q000254:growth & development / Q000502:physiology*; D014197:Trees / Q000254:growth & development / Q000502:physiology*; D014329:Tropical Climate; D014867:Water / Q000378:metabolism; D058438:Water Cycle
chemical_list: D014867:Water