title: Carbon: nitrogen stoichiometry following afforestation: a global synthesis.
abstract: Though carbon (C): nitrogen (N) stoichiometry has been widely studied in terrestrial ecosystems, little is known about its variation following afforestation. By synthesizing the results of 53 studies, we examined temporal and spatial variation in C: N ratios and in N-C scaling relationships of both the organic and the mineral soil horizons. Results showed that C: N ratios remained constant in the mineral horizon but significantly decreased in the organic horizon over the age sequence following afforestation. Among different climate zones, C: N ratios of the organic and the mineral horizons increased and decreased, respectively, with increasing mean annual temperature (MAT) (decreasing latitude). Pasture exhibited higher C: N ratios than cropland in the organic horizon while C: N of the mineral horizon did not change much among different land use types. For both the organic and the mineral horizons, hardwoods exhibited lower C: N ratios than pine and softwoods. Additionally, N and C in general scaled isometrically in both the organic and the mineral horizons over the age sequence and among different climate zones, land use types, and plantation species following afforestation. Our results suggest that C and N may remain coupled following afforestation.
authors.affiliation: Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China.|Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA.
authors.forename: Xia
authors.initials: X
authors.lastname: Xu
authors.affiliation: Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China.
authors.forename: Dejun
authors.initials: D
authors.lastname: Li
authors.affiliation: Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China.
authors.forename: Honghua
authors.initials: H
authors.lastname: Ruan
authors.affiliation: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA.
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Luo