Soil carbon stabilization along productivity gradients in interior Alaska: Summer 2003

Boreal forests in a warmer future climate are likely to exhibit altered productivity levels, tightened fire return intervals, and increased decomposition rates to varying degrees across the landscape. This research focuses on mechanisms of soil C stabilization in P. mariana systems along gradients in stand productivity. Charred material in the soil will be quantified to understand the lasting effect of fire on the stabilization of soil C. The interaction between temperature and productivity in relation to the stabilization of soil C will be investigated by monitoring climate and soil temperatures along the productivity gradients and through laboratory incubations of soil. Research questions are addressed in three main areas of inquiry: 1) how the interaction between stand production and landscape position effect the stabilization of C throughout the soil profile, 2) how the contribution of burn residues to total C accumulation varies across the landscape, and 3) the relationship between aboveground productivity and burn residues across the landscape. The overall goal is to apply an understanding of the biophysical controls on C storage in the boreal forest to the landscape level.

在未来气候变暖的情景下，北方针叶林的生产力水平或将发生改变，林火轮回期将缩短，且全域景观区域的有机质分解速率将呈现不同程度的提升。本研究聚焦于沿林分生产力梯度分布的黑云杉（P. mariana）林分的土壤碳固持机制。研究将通过量化土壤中的炭化物质，厘清林火对土壤碳固持的长期影响；同时沿生产力梯度监测气候与土壤温度，并结合土壤室内培养试验，探究温度与生产力的交互作用对土壤碳固持的调控机制。本研究的核心问题涵盖三大探究方向：1）林分生产力与景观区位的交互作用如何调控整个土壤剖面的碳固持过程；2）火烧残余物对总碳积累的贡献如何随景观异质性发生变化；3）地上生产力与火烧残余物之间的关联如何随景观梯度改变。本研究的总体目标是将对北方针叶林碳储存的生物物理调控机制的认知，拓展至景观尺度。