中国北方林生产力变化趋势及其影响因子分析

Modeling Variation Trend of Boreal Forest NPP in China and Its Relations to Temperature and Precipitation

森林生产力是反映森林固碳能力的重要指标 ,是进行碳循环研究的重要环节 .用模拟生态系统生物地球化学循环的 CENTURY模型 ,模拟中国北方林 兴安落叶松林 近 35 a来的生产力动态 ,用 3种趋势分析方法 ,检验了其变化趋势 ,并用多元线性回归模型分析了中国北方林生产力的年际波动与气温降水年际波动的关系 ,以及气温和降水对我国北方林生产力的影响程度 .结果表明 :中国北方林生产力呈增加的趋势 ,平均年增长率为 0 .34% ;气温与森林生产力呈显著负相关 ,对森林生产力的贡献因子为 4 .0 977;降水与森林生产力呈弱的正相关 ,其对森林生产力的贡献因子为 0 .390 2 .从而说明近 35 a来森林生产力的增加除了受气温降水等非生物因素的影响外 ,还受其它因素的影响 ;另外说明以气候变暖为标志的全球变化会对森林生产力产生重要的影响 .

Forests are an important vegetation type,and play a key role in global change and terrestrial (ecosystem) cycle.Forest net primary production (NPP) reflect the quantity that forest sequestration carbon and thus NPP is an important component of the carbon cycle,and among the pools and fluxes that make up the cycle.In this study terrestrial ecosystem process model CENTURY 4.0 model was used to investigate the dynamics of boreal forest (Larix gmelinii forest) NPP in recent 35 years as well as annual mean temperature and precipitation.Based on three trend analyzing methods (average,least square fitting,slope AR(1) process),the variation trends of boreal forest NPP was tested.The results showed that increasing trends of boreal forest NPP were very significant,and the annual increasing rate of boreal forest NPP was (0.34%).The multi-regression and correlation analysises showed that a significant negative correlation existed between boreal forest NPP and annual mean temperature,but the correlation between boreal forest NPP and annual precipitation was positive correlation;the factor analyzing method suggested that the effect of temperature on boreal forest NPP be larger than that of precipitation and this indicated that climate warming would greatly influence vegetation NPP.This study might be helpful not only to evaluate the trends of vegetation NPP,but also to accurately estimate effects of climatic factors on vegetation NPP.