Brad Oberle, Marissa R. Lee, Jonathan A. Myers, Oyomoare L. Osazuwa-Peters, Marko J. Spasojevic, Maranda L. Walton, Darcy F. Young, Amy E Zanne

Deadwood is a large aboveground carbon (C) pool that regulates how forests respond to global change. Due to slow decomposition, CWD delays C emissions following major forest disturbances so predicting how carbon balance will respond to changing disturbance regimes requires identifying factors that influence the full temporal trajectory of wood decay from senescence to complete mineralization. However, typical experiments only examine how wood decay begins with unknown consequences for scaling short-term results up to long-term forest ecosystem projections. Using a 7-year experiment that captured complete mineralization among 21 temperate tree species, we demonstrate that (1) wood traits are more important than environmental drivers, (2) trait effects fade with advancing decay and (3) permeability-related traits control how decay rates change through time. Only long-term data and a time-varying model yielded accurate predictions of both mass loss in a concurrent experiment and naturally-recruited deadwood structure in a 32-year old forest plot. Given the importance of forests in the carbon cycle, and the pivotal role for wood decay, accurate ecosystem projections are critical and they require experiments that go beyond enumerating potential mechanisms by identifying the temporal scale for their effects.