Measuring the Decomposition of Down Dead-Wood

Abstract

Down and dead-wood plays an important ecological role in forest ecosystems, and the decomposition of this material may contribute significantly to forest net ecosystem production. Dead-wood decomposition can be measured in three ways: measuring variability in density over a chronosequence of dead-wood, measuring density changes during a time series of decomposition, and measuring dead-wood respiration rates in conjunction with estimates of dead-wood mass. For sites selected for intensive carbon cycle studies, we suggest a two-prong approach to measuring down dead-wood decomposition. First, initial estimates should be based on a chronosequence of samples stratified by size (1–10 cm diameter, >10 cm diameter). Radiocarbon measurements of the wood in different growth increments should be used to age the material if accurate stand history (mortality) data are not available. Second, we suggest establishing a time-series decomposition experiment to quantify rates of carbon release during the decomposition process. These samples should be stratified by diameter (as above) and by length (approximately 10-times the diameter). This combination of approaches will yield both short- and long-term values for the contribution of dead wood to net carbon sequestration in forest ecosystems, including estimates of associated uncertainty.