Biomass, thermal inertia, and radiative freeze occurrence in leafless forests

Using field measurements of air temperature, wind, and relative humidity fr om a clear-cut site and two wooded sites in northern Wisconsin, we used a r adiative transfer model to simulate temperatures on seven calm, clear night s similar to those on which freezes typically occur. Each night was simulat ed twice for the wooded sites. One simulation ignored the presence of veget ation, the other approximated the vegetation's heat storage capacity and it s influence on air temperatures. The simulations including biomass heat sto rage showed smaller mean absolute temperature errors and decreased magnitud e of systematic model error when compared with the simulations ignoring veg etation. The results suggest that the thermal inertia of forest biomass may play a significant role in controlling forest temperatures on calm, clear nights and, hence, in controlling freeze occurrence.