title: Recovery time of soil carbon pools of conversional Chinese fir plantations from broadleaved forests in subtropical regions, China.
abstract: The conversion from natural forest to plantation has been widely applied, with consequences on ecosystem carbon pool. The experimental results of changes of soil carbon stocks after forest conversion are often contradictory. Moreover, the recovery time of soil carbon stocks after forest conversion varies among different sites. To examine the changes of soil carbon stocks following the forest conversions in the long-term and to estimate the recovery time, we selected 116 subtropical forests, including 29 pair-wise replicates for evergreen broadleaved forests (EBF, 40-100-year-old), young Chinese fir plantations (Cunninghamia lanceolata) (YCP, 4-8-year-old), middle-aged Chinese fir plantations (MACP, 13-20-year-old), and mature Chinese fir plantations (MCP, 23-32-year-old), and estimated soil carbon stocks. Soil carbon stocks of YCP and MACP decreased in average 12.5 and 28.7Mgha-1compared with EBF, and showed no variation between MCP and EBF. Soil carbon stocks were positively correlated to soil total nitrogen stocks and C:N ratio. Our results showed that the forest conversions didn't cause a variation of soil carbon stocks in the long-term, although there was a short-term decline after conversion. The recovery time of soil carbon stock is 27years. These results indicate that the conversion from evergreen broadleaved forests to Chinese fir plantations in subtropical region of China causes soil carbon release in early stage, but has no effect on soil carbon stocks in the long-term. Prolonging the rotation period (>27years) would offset the adverse effects of the forest conversion on soil carbon stocks, and be critical in alleviating global climate change.
authors.affiliation: Huitong Experimental Station of Forest Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China. Electronic address: lcchen@iae.ac.cn.
authors.forename: Long-Chi
authors.initials: LC
authors.lastname: Chen
authors.affiliation: College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China. Electronic address: wangchina926@163.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: Huitong Experimental Station of Forest Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.affiliation: Huitong Experimental Station of Forest Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Zhang
authors.affiliation: Huitong Experimental Station of Forest Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: Xiao-Tao
authors.initials: XT
authors.lastname: Lü
authors.affiliation: Huitong Experimental Station of Forest Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Huitong National Research Station of Forest Ecosystem, Huitong 418307, China. Electronic address: slwang@iae.ac.cn.
authors.forename: Si-Long
authors.initials: SL
authors.lastname: Wang
keywords: Chinese fir plantation; Evergreen broadleaved forest; Forest conversion; Soil carbon stock; Soil total nitrogen stock