Harvard Forest Research

Warming effects on wood decomposition and wood decomposing communities.

Principal Investigator: Aaron Ellison
Harvard Forest: Jul 01 2009 - Aug 31 2012:

Abstract:
Woody debris is an important global carbon (C) pool and decomposition may represent a positive feedback to climate change as respiration generally increases exponentially with temperature. This response could be vital to future carbon cycling as the Intergovernmental Panel on Climate Change (2007) predicts that global temperatures will increase by 1.1- 6.4 °C by 2100. Fungi likely play a large role in C and nutrient cycling in forests as enzymes excreted by fungi allow metabolism of recalcitrant organic substrates, such as lignin and cellulose to which few other organisms have access. In total, fungi produce up to 90% of soil respiration. Functional processes and community structure are not often measured at the same time in current literature; however in this study I will use a combination of methods to measure the response of both the community structure and function of wood decomposing microbial communities to increasing temperature.

I will take advantage of a manipulative warming experiment including ten 5-m open-top warming chambers at each of two sites, the Harvard Forest Long Term Ecological Research site (HFR), in Petersham, Massachussetts, and the Yates Forest at Duke University (YNC). I will install four logs of locally acquired Red Maple (Acer rubrum) in each of ten chambers; one or two living trees will be felled from hardwood stands near each site and divided into segments 30-cm long and about 5cm in diameter. Eight small A. rubrum twigs will be placed in separate 6 x18cm decomposition bags in each chamber. Mass loss, wood quality, potential enzyme activity, macroinvertibrate community structure, microbial community structure and bacteria:fungi abundance will be measured from samples removed at 0, 31, 123, 243, 427, 608, 792, 974 and 1096 days.

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