Wednesday, May 18, 2005
Long-term carbon dynamics of an old-growth Douglas-fir forest
Temporal changes in forest ecosystem carbon stocks is a poorly understood process. With relevance to global change policy and carbon accounting and trading it is important for scientists to provide accurate information on this largely unknown compartment of the global carbon cycle and provide baseline data on which to establish continuous regional and continental scale monitoring programs. At the Wind River Canopy Crane Research Facility (WRCCRF) in south-central Washington state, efforts are underway to measure carbon dynamics in an old-growth Douglas-fir forest. These forests have large accumulations of biomass and exchange significant amounts of carbon with the atmosphere. Between 1997 and 2003 the WRCCRF old-growth forest stand was on average a slight carbon sink (0.8 Mg per hectare per year) and ranged from a minor source (-0.5 Mg per hectare per year) to a significant sink (2.2 Mg per hectare per year). This is counter to the long held paradigm that such old-growth forests are large and continuous sources of carbon. Three different methodologies for carbon measurement are employed at the WRCCRF: traditional biophysical measurements and allometrics, stable isotope ratio analysis, and eddy flux correlation. Each method has inherent problems; however, they represent the best available science for this important task.
Dr. Ken Bible began a career in forest ecosystem research in 1986 with the Uplands Field Research Lab in the Great Smoky Mountains NP using permanent sample plots in spruce/fir forest to assess long-term impacts of acid deposition, ozone and biological pathogens on vegetation. He has a Ph.D. in Ecosystem Science from the University of Washington College of Forest Resources and is currently Site Director of the Wind River Canopy Crane Research Facility. Dr. Bible's research interests include long-term population dynamics of tree species, mechanisms affecting forest ecosystem structural development and function, development and application of long-term environmental monitoring methods, sensor arrays, and database design.