Woods Hole Research Center

Forests are an important component of the global carbon cycle. Each year, they withdraw carbon from the atmosphere through photosynthesis and release it to the atmosphere through both plant and microbial respiration (Figure 1). The processes of photosynthesis and respiration are strongly affected by climatic conditions, particularly temperature and precipitation. With a changing global climate, the role forests play in the uptake and release of carbon could be altered.

Figure 1: The terrestrial carbon cycle

Soil respiration is the loss of carbon in the form of CO2 from soils as a result of both microbial decomposition and root respiration. Both temperature and moisture play an important part in determining soil respiration rates. Soil temperature plays a significant role in accounting for the seasonal and daily variations in respiration rates; however, moisture plays a more complicated role, often reducing respiration rates when soils are either very wet or very dry.

Research Associate Kathleen Savage measures soil respiration at Harvard forest.

Woods Hole Research Center studies are focusing on several aspects of the forest carbon cycle, including how temperature and moisture affect the release of carbon through soil and dead-wood respiration, how standing forest biomass contributes to carbon storage, and the development of models to predict how forest carbon storage is affected by variation in temperature and precipitation.

At the Harvard Forest, in western Massachusetts, Woods Hole Research Center scientists are measuring soil respiration and examining the effects of climatic variables through long term plots and amendment experiments.

By studying carbon cycling in forests, Center scientists will be better able to judge the nature and extent of the role played by forests in alleviating global warming through the absorption of atmospheric carbon. It is already well recognized that forests provide such valuable services as timber, clean water, and wildlife habitat. But scientific evidence of the role that New England forests play in mitigating the effects of global warming could significantly bolster local, national, and global conservation efforts on behalf of these forests.