Dendroecological Applications to Coarse Woody Debris Dynamics

Abstract

Coarse woody debris plays a crucial role in forest ecosystems. The current amount of woody debris on a given site represents a balance between additions (tree mortality) and depletions (wood decomposition, combustion, transport). Understanding woody debris dynamics has recently gained much attention, primarily because of the need to improve forest carbon accounting and modelling. Woody debris itself also holds great potential for use in dendrochronological studies, including those aimed at revealing forest stand dynamics. As such, tree-ring data from woody debris is at times used to make inferences about past stand dynamics; however, at other times tree-ring data from samples in close proximity to woody debris are used to make inferences about the dynamics of woody debris itself. Our case study provides an example of the latter application by addressing woody debris dynamics in three old-growth Picea rubens stands in Maine, USA. Our findings show striking fluctuations in woody debris mass over a 100-year period (1900-2000), with pulses in woody debris inputs corresponding to reconstructed forest disturbances. These fluctuations highlight the need to characterize woody debris dynamics for refining modelling efforts and developing restoration prescriptions in ecosystems with disturbance regimes dominated by gap- and meso-scale disturbances.