干扰和非干扰因子对东北地区森林碳收支的贡献

Forests play an irreplaceable role in the Earth’s terrestrial carbon sinks which retard the atmospheric CO2 buildup. Forest carbon budget is affected by both disturbance and non-disturbance factors. Quantifying the contributions of these forcing factors to forest carbon budget is the best way to understand the mechanism of forest carbon sink dynamics. Northeast China has the largest forest area in China. However, the quantitative contribution of different drivers to the trends of forest carbon budget remain unclear in this region. This study is to estimate forest carbon budget in Northeast China and evaluate their responses to disturbance (stand age, forest fires) and non-disturbance (climate change, atmospheric CO2 concentration, nitrogen deposition) factors by integrating regional data sets, the updated Integrated Terrestrial Ecosystem Carbon Cycle (InTEC) model, and factorial simulations. The main research contents include the following: (1) Examining the change characteristics of NPP with stand age to develop functions describing the NPP-age relationship for different forest types which are used to update the InTEC model; (2) Simulating the spatio-temporal distributions of forest carbon budget during the period from 2000 to 2017 with consideration of both disturbance and non-disturbance effects based on the updated InTEC model; (3) Identifying the contributions of stand age, fires, climate variability, atmospheric CO2 concentration, nitrogen deposition to forest carbon budget through a series of factorial simulations of the updated InTEC model separately quantifying the effect of each factor. This study can provide scientific guidance and reference for optimizing the estimation of forest carbon budget, maximizing the profit of forestry and enhancing forest carbon sequestration at the regional scale.

森林对陆地生态系统碳汇具有非常重要的作用，其碳收支受到干扰和非干扰因子的共同影响。定量区分这些因子对森林碳收支的驱动作用，是准确预测森林碳汇变化趋势的重要途径。东北是我国的最大林区，但不同因子对该地区森林碳收支变化的贡献尚不清楚。本项目将以东北地区森林为研究对象，通过数据集成分析、InTEC碳循环模型优化和模拟试验，明晰东北地区森林碳收支的变化特征，鉴别干扰（林龄、火灾）和非干扰（气候、CO2浓度、氮沉降）因子的驱动作用。主要研究内容包括：（1）东北地区不同森林类型NPP随林龄变化的特征，确定描述NPP-age关系的数学方法，并应用于优化InTEC模型；（2）2000-2017年东北地区森林碳收支时空变化特征；（3）林龄、火灾、气候、CO2浓度和氮沉降对东北地区森林碳收支变化的贡献。研究成果将对优化计算区域森林的碳收支、改进森林管理和增强森林碳汇功能具有重要的科学意义和参考价值。