Coarse Woody Debris Decomposition Assessment Tool: Model validation and application

• Published in: PloS one Vol. 16; no. 7; p. e0254408
• Main Authors: Dai, Zhaohua, Trettin, Carl C, Burton, Andrew J, Jurgensen, Martin F, Page-Dumroese, Deborah S, Forschler, Brian T, Schilling, Jonathan S, Lindner, Daniel L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 09.07.2021; Public Library of Science (PLoS)
• Subjects: Betula papyrifera; Biology and Life Sciences; Biomass; Calibration; Carbon; Carbon - analysis; Carbon cycle; Carbon dioxide; Climate models; Climatic conditions; Correlation coefficient; Correlation coefficients; Debris; Decomposition; Detritus; Dissolved organic carbon; Earth Sciences; Ecology and Environmental Sciences; Environmental science; ENVIRONMENTAL SCIENCES; Forest biomass; Forest carbon; Forests; Funding; Hardwoods; Hurricanes; Hydrology; Measurement; Models, Theoretical; Nutrient cycles; Organic carbon; Physical Sciences; Pine; Pine trees; Pinus - chemistry; Pinus taeda; Populus tremuloides; Precipitation; Research and Analysis Methods; Science & Technology - Other Topics; Sea level; Simulation; Soil - chemistry; Soil conditions; Soils; Watersheds; Wood; Wood - chemistry; United States; North Carolina; California; United States > US; South Carolina; Michigan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0254408

Coarse woody debris (CWD) is a significant component of the forest biomass pool; hence a model is warranted to predict CWD decomposition and its role in forest carbon (C) and nutrient cycling under varying management and climatic conditions. A process-based model, CWDDAT (Coarse Woody Debris Decomposition Assessment Tool) was calibrated and validated using data from the FACE (Free Air Carbon Dioxide Enrichment) Wood Decomposition Experiment utilizing pine (Pinus taeda), aspen (Populous tremuloides) and birch (Betula papyrifera) on nine Experimental Forests (EF) covering a range of climate, hydrology, and soil conditions across the continental USA. The model predictions were evaluated against measured FACE log mass loss over 6 years. Four widely applied metrics of model performance demonstrated that the CWDDAT model can accurately predict CWD decomposition. The R2 (squared Pearson's correlation coefficient) between the simulation and measurement was 0.80 for the model calibration and 0.82 for the model validation (P<0.01). The predicted mean mass loss from all logs was 5.4% lower than the measured mass loss and 1.4% lower than the calculated loss. The model was also used to assess the decomposition of mixed pine-hardwood CWD produced by Hurricane Hugo in 1989 on the Santee Experimental Forest in South Carolina, USA. The simulation reflected rapid CWD decomposition of the forest in this subtropical setting. The predicted dissolved organic carbon (DOC) derived from the CWD decomposition and incorporated into the mineral soil averaged 1.01 g C m-2 y-1 over the 30 years. The main agents for CWD mass loss were fungi (72.0%) and termites (24.5%), the remainder was attributed to a mix of other wood decomposers. These findings demonstrate the applicability of CWDDAT for large-scale assessments of CWD dynamics, and fine-scale considerations regarding the fate of CWD carbon.