New England Forest Ecology

Carbon, in the form of carbon dioxide (CO₂), is an important greenhouse gas released to the atmosphere through both natural and human activity. The concentration of CO₂ in the atmosphere has increased since the start of the industrial revolution, and a continued release of greenhouse gases threatens to disrupt global climatic patterns.

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 (Fig. 1). The processes of photosynthesis and respiration are strongly affected by climatic conditions, particularily 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

In order to gain a better understanding of how forests are involved in the cycling of carbon, we have been participating in collaborative studies examining forest respiration and photosynthesis at two New England study sites: one in Howland, Maine, and one at Harvard Forest in central Massachusetts (Fig. 2). Our research effort focuses 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. Projects at Howland Forest included an investigation of how disturbance (nitrogen deposition and management) alters the carbon budget of this forest.

By studying carbon cycling in forests, we hope to 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.

To learn more about this project, see Harvard Forest study, or Howland, Maine forest study.

©Woods Hole Research Center, 2007