The plant afterlife: How wood construction determines deadwood carbon flux

Background/Question/Methods Woody plant stems provide a large biological carbon store. As plants senesce and decay, this carbon returns to the atmosphere. Studies have shown environmental conditions affect decay rates; however, we know much less about how anatomical and chemical construction of plant species affects these rates, especially how different constructions control colonization by different saprobes. We monitored deadwood decay in rot plots in the Ozark Highlands from 21 species of woody plants. These plants vary in their phylogenetic history, as well as chemical and anatomical construction.

Results/Conclusions Within 3 years of decay, species lost on average ~50% of their biomass, but variation across species was considerable (13-92%). By 5 years of decay, stems of some species were no longer recognizable. This variation was better predicted by plant species membership than location in the landscape with gymnosperms and angiosperms showing considerable differences. The underlying plant traits best explaining these differences were chemical rather than anatomical, with differences in carbon fractions being especially important. Fungal communities varied considerably among plant species leading to differences in fungal enzyme expression. Hydrolases were higher in logs with high mass loss, while differences in peroxidases were less clear. Taken together, construction of plants while they are living places strong controls on who colonizes them and how they decay once they are dead.