Journal of Geographical Sciences ›› 2011, Vol. 21 ›› Issue (3): 458-474.doi: 10.1007/s11442-011-0857-2

• Ecology • Previous Articles     Next Articles

Assessing productivity and carbon sequestration capacity of subtropical coniferous plantations using the process model PnET-CN

YAN Yuan1,2, WANG Shaoqiang1, WANG Yidong1,2,4, WU Weixing1,2, WANG Jingyuan1, CHEN Bin3, YANG Fengting4   

  1. 1. Key Laboratory of Ecosystem Network Observation and Modeling (KLENOM), Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China;
    3. School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada;
    4. Qianyanzhou Ecological Experimental Station, KLENOM, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
  • Received:2010-05-07 Revised:2010-11-20 Online:2011-06-15 Published:2011-06-15
  • Supported by:

    National Natural Science Foundation of China, No.31070438; The Key Project of CAS Knowledge Innovation Program, No.KZCX2-YW-305-3; No.KZCX2-YW-QN301; State Key Basic Research Development Project, No.2010CB833503

Abstract:

A generalized, lumped-parameter ecological model PnET-CN was calibrated and validated for a subtropical coniferous plantation in southern China. PnET-CN model describes the biogeochemical cycles of carbon (C) and nitrogen (N) and can assist in estimating carbon sequestration potential. For validation of PnET-CN, data from coniferous forest plantations in southern China was used. Simulated daily gross primary productivity (GPP) from 2005 to 2007 agreed well with observations (R2=0.56, S.D.=0.009). Simulations of monthly soil respiration (Rs) from 2005–2007 agreed well with Rs observations (R2=0.67, S.D. =0.03). Simulated annual net primary productivity (NPP) from 1998–2006 was 803±33 gCm-2a-1, about 4% higher than NPP observation (752±51 gCm-2a-1). Simulations of annual NEP from 2005-2007 only overestimate 9 gCm-2a-1 (4%), 4 gCm-2a-1 (1%) and 34 gCm-2a-1 (8%) compared to NEP observations, respectively. Simulated annual foliar N concentration (FolNCon) (1.09%) is 10% lower than observed monthly FolNCon (0.87%–1.58%). Simulated annual N leaching (0.26 gNm-2) is about 10% lower than leaching observation (0.29 gNm-2). PnET-CN model validation indicates that PnET-CN is capable to simulate daily GPP, annual NPP, annual NEP, monthly Rs, annual FolNCon and annual nitrate N leaching for subtropical coniferous plantations in southern China. The results obtained from the validation test revealed that PnET-CN model can be used to simulate carbon sequestration of planted coniferous forests in southern China to a high level of precision. Sensitivity analysis suggests that great care should be taken in developing generalizations as to how forests will respond to a changing climate. PnET-CN performed satisfactorily in comparison to other models that have already been calibrated and validated in coniferous planted subtropical forests in China. Based on PnET-CN validation and its comparison to other models, future improvement of PnET-CN should focus on seasonal foliar N dynamics and the effects of water stress on autotrophic respirations in subtropical coniferous plantations in southern China.

Key words: coniferous plantations, PnET-CN Model, validation, foliar N concentration, C sequestration