OOS 32-1 - An integrated perspective of woody carbon in forests: The live to soil continuum

Wednesday, August 8, 2012: 1:30 PM
B113, Oregon Convention Center
Mark E. Harmon, Forest Ecosystems and Society, Oregon State University, Corvallis, OR

Carbon is stored in many forms of live and dead woody materials within forests ranging from wood and bark stored above- and belowground to highly decomposed soil-like residues.  Current knowledge about the production and growth of living woody plants is vastly superior to that the dead part of the system; yet understanding of forest ecosystem function depends upon a more equitable understanding that spans the entire live to soil continuum.  For example, some emergent properties at the ecosystem level can not be explained without the feedbacks between live and dead woody material.  While aspects of fine litter decomposition can be applied toward woody litter, the latter involves physical and biological aspects that are not analogous to the former. Woody materials can: 1) vary in size by at least 3 orders of magnitude leading to vastly different wetting, drying, and colonization rates; 2) be self-supporting expanding the range of microenvironments they encounter relative to fine litter, and 3) be degraded by organisms that target lignin as a substrate.  Unfortunately many existing simulation models fail to consider these differences and are unlikely to predict the kinds of phenomenon (e.g., lags) likely to significantly alter ecosystem behavior. 


To address the imbalance in knowledge of live versus dead woody material, ecological sciences will need to rapidly improve understanding of the processes of mortality, respiration, leaching, fragmentation (e.g., snag fall), and combustion as well as how climate, the chemical and physical nature of dead wood, and decomposer organisms control these processes.  While the traditional mode of many separate, small scale research efforts may eventually close this knowledge gap, there is an immediate need for predicting ecosystem behavior which suggests an integrated, coordinated broad-scale approach would likely be more fruitful.