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

• Published in: Journal of geographical sciences Vol. 21; no. 3; pp. 458 - 474
• Main Authors: Yan, Yuan, Wang, Shaoqiang, Wang, Yidong, Wu, Weixing, Wang, Jingyuan, Chen, Bin, Yang, Fengting
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science Press 01.06.2011; Springer Nature B.V
• Subjects: Applied ecology; Bgi / Prodig; Biogeochemical cycles; Biogeography; Carbon sequestration; Climate change; Coniferous forests; Earth and Environmental Science; Ecological models; Forests; Geographical Information Systems/Cartography; Geography; Leaching; Nature Conservation; Physical Geography; Plantations; Productivity; Remote Sensing/Photogrammetry; Respiration; Seasonal variations; Sensitivity analysis; Simulation; Water stress; 亚热带森林; 总初级生产力; 生物地球化学循环; 碳吸存; 过程模型; 针叶林; Southern China; China; China, People's Rep; PnET-CN Model; coniferous plantations; C sequestration; validation; foliar N concentration; Subtropical zone; Conifer; Model; Ecology; Plantation; Nitrogen; Carbon sequestration; Experimental station
• ISSN: 1009-637X; 1861-9568
• DOI: 10.1007/s11442-011-0857-2

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）. Simu- lated 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 planta- tions 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.