内蒙古大兴安岭森林净初级生产力时空格局分析

目的 通过模型模拟分析内蒙古大兴安岭地区森林生产力时空分布格局及其驱动因子。 方法 利用优化率定后的生理生态过程模型Biome-BGC参数，模拟了内蒙古大兴安岭地区时间序列（2003—2012年）森林净初级生产力（NPP）。基于外业实测数据，在全区域尺度上进行NPP模拟结果验证。 结果 优化率定后的Biome-BGC模拟的该区森林NPP具有较高可靠性，实测数据验证 R2为0.81， RMSE 为48.73 g·m-2·a-1。2003—2012年间该区森林NPP为219.3~399.5 g·m-2·a-1，其中针叶林NPP为218.6~414.9 g·m-2·a-1、阔叶林为213.7~412.3 g·m-2·a-1、混交林为188.3~404.7 g·m-2·a-1。森林NPP与温度和太阳辐射的相关性较高（ R2分别为0.55和0.49），与降水量和相对湿度的相关性较低。 结论 时间序列上该区森林NPP年平均值总体呈缓慢增长趋势；空间分布呈北高南低，东部偏低的特征。"天然林保护工程"的实施是该区森林NPP增加的主要因素，而火灾则降低了森林NPP，二者造成了该区NPP呈现时空差异；不同森林类型NPP差异主要受温度和太阳辐射的影响。

Analysis of Spatial-temporal Pattern of Forest Net Primary Productivity of the Great Khingan in Inner Mongolia

Objective To analyze the spatial and temporal distribution patterns and driving factors of forest productivity in Daxing'anling of Inner Mongolia by model simulation. Method The optimized and calibrated physiological parameters of the ecological process model, the Biome-BGC, performed in a previous study were applied to simulate the long-term (from 2003 to 2012) forest net primary productivity (NPP) over the Daxing'anling region in Inner Mongolia. Based on forest dendrochronological measurements, the simulated NPPs were validated at a regional scale. Result The simulated forest NPPs from the calibrated Biome-BGC model had high reliability with R2=0.81 and RMSE =48.73 g·m-2·a-1. From 2003 to 2012, the forest NPP ranged from 219.3 to 399.5 g·m-2·a-1, of which coniferous forest NPP ranged from 218.6 to 414.9 g·m-2·a-1, broadleaved forest 213.7 to 412.3 g·m-2·a-1 and mixed forest 188.3 to 404.7 g·m-2·a-1 respectively. The correlation between forest NPP and temperature and solar radiation was higher ( R2 was 0.55 and 0.49), and the precipitation and relative humidity was lower. Conclusion In time series, the annual average of forest NPP in this area shows a slow growth trend, while the spatial distribution shows the characteristics of high in the north and low in the south and east. The implementation of "Natural Forest Conservation Project" is the main factor driving the increase of forest NPP in this area, while fire decreases forest NPP, which results in the spatial and temporal differences of NPP in this area. The differences of NPP in different forest types are mainly affected by temperature and solar radiation.