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亚热带森林生态系统具有巨大的固碳潜力。净初级生产力(NPP)在碳循环过程中具有重要的作用,受到气候变化、大气成分、森林扰动的强度和频度、林龄等因子的综合影响,然而目前上述各因子对亚热带森林NPP变化的贡献尚不明确,需要鉴别森林NPP时空变化的主要驱动因子,以准确认识亚热带森林生态系统碳循环。该文综合气象数据、年最大叶面积指数(LAI)、参考年NPP(BEPS模型模拟)、林龄、森林类型、土地覆盖、数字高程模型(DEM)、土壤质地、CO2浓度、氮沉降等多源数据,利用In TEC模型(Integrated Terrestrial Ecosystem Carbon-budget Model)研究亚热带典型地区江西省森林生态系统1901–2010年NPP时空动态变化特征,通过模拟情景设计,着重讨论1970–2010年气候变化、林龄、CO2浓度和氮沉降对森林NPP动态变化的影响。研究结果如下:(1)In TEC模型能较好地模拟研究区NPP的时空变化;(2)江西省森林NPP 1901–2010年为(47.7±4.2)Tg C·a–1(平均值±标准偏差),其中20世纪70年代、80年代、90年代分别为50.7、48.8、45.4 Tg C·a–1,2000–2009年平均为55.2 Tg C·a–1;随着森林干扰后的恢复再生长,江西省森林NPP显著上升,2000–2009年NPP增加的森林面积占森林总面积的60%;(3)1970–2010年,仅考虑森林干扰因子和仅考虑非干扰因子(气候、氮沉降、CO2浓度)情景下NPP分别为43.1和53.9 Tg C·a–1,比综合考虑干扰因子和非干扰因子作用下的NPP分别低估7.3 Tg C·a–1(低估的NPP与综合考虑干扰因子和非干扰因子作用下NPP的比值为14.5%,下同)和高估3.6 Tg C·a–1(7.1%);气候因子导致平均NPP减少2.0 Tg C·a–1(4.7%),氮沉降导致平均NPP增加4.5 Tg C·a–1(10.4%),CO2浓度变化及耦合效应(氮沉降+CO2浓度变化)分别导致平均NPP增加4.4 Tg C·a–1(10.3%)和9.4 Tg C·a–1(21.8%)。
Subtropical forest ecosystems have great carbon sequestration potential. Net Primary Productivity (NPP) plays an important role in the carbon cycle and is affected by the combined effects of climate change, atmospheric composition, intensity and frequency of forest disturbance, and age of the forest. However, the current NPP changes of NPP in subtropical forests Contributions are not yet clear and need to identify the main drivers of spatio-temporal changes in forest NPP in order to accurately understand the carbon cycle in subtropical forest ecosystems. In this paper, comprehensive meteorological data, annual maximum LAI, reference NPP (BEPS model simulation), forest age, forest type, land cover, DEM, soil texture, CO2 concentration, Source data, the temporal and spatial dynamic characteristics of NPP in 1901-2010 years in Jiangxi subtropical forest were studied by using In-ter Model (Integrated Terrestrial Ecosystem Carbon-budget Model). By simulating the scenario design, the climate change in 1970-2010 was mainly discussed. Effects of Nitrogen, CO2 Concentration and Nitrogen Deposition on the Dynamic Change of Forest NPP. The results are as follows: (1) The In TEC model can better simulate the spatio-temporal changes of NPP in the study area; (2) The forest NPP in Jiangxi Province from 1901 to 2010 was (47.7 ± 4.2) Tg C · a-1 Deviations), of which 50.7,48.8,45.4 Tg C · a-1,2000-2009 average 55.2 Tg C · a-1 in the 1970s, 1980s and 1990s respectively. With the restoration of forest disturbance NPP of Jiangxi Province increased significantly from 2000 to 2009, accounting for 60% of the total forest area; (3) In 1970-2010, only forest disturbance factor and only non-interference factor were considered (climate and nitrogen deposition And CO2 concentration), NPP was 43.1 and 53.9 Tg C · a-1, respectively, underestimating 7.3 Tg C · a-1 (NPP under comprehensive consideration of interference factor and non-interference factor) And non-interfering factor (NPP) ratio of 14.5%, the same below) and an overestimation of 3.6 Tg C · a-1 (7.1%). Climatic factors resulted in a decrease of average NPP of 2.0 Tg C · a -1 (4.7% The mean NPP increased by 4.5 Tg C · a-1 (10.4%), CO2 concentration and the coupling effect (nitrogen deposition + CO2 concentration change) resulted in the increase of average NPP by 4.4 Tg C · a-1 (10.3% ) And 9.4 Tg C · a-1 (21.8%).