Wood decay in the Ozark Highlands: variation across species, space, and time

One of the largest terrestrial biological stores of carbon is wood. 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 fungi. We established wood decay plots in ridgetops and valley bottoms in the Ozark Highlands with logs from 21 species of woody plants. These plants vary in their carbon fractions and nutrient contents, as well as size and type of water conducting vasculature. After 1 year of decay, species lost on average 27% of their biomass and by 3 years of decay species lost on average 52% of their biomass. But, variation in mass loss across species was considerable (16-92%). This variation was better predicted by plant species membership than location in the landscape. The underlying plant traits best explaining these differences were chemical rather than anatomical. 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 when they are dead.