Heat storage in a young eucalypt forest

Abstract

Diurnal temperature changes of leaves, twigs, branches, trunks, boles, litter and air were measured in a young eucalypt forest. The distribution of biomass within the community was determined and was combined with temperature data and mass averaged heat capacities to determine the rate of change of heat storage. Different patterns of temperatures of the various components are presented. The heat storage, on clear days, was shown to be positive during the morning and negative during the afternoon. Storage fluctuated on days with broken clouds. An empirical model which related heat storage in the biomass and in the canopy air volume to the time rate of change of air temperature was determined. The model was tested with an independent data set and proved satisfactory. A 1°C h −1 air temperature rise was equivalent to approximately 0.39 W m −2 rate of change of heat storage for each kg m −2 of fresh biomass material. Heat storage computed by this model was combined with the Bowen ratio method to compute forest evaporation and it was found that the inclusion of heat storage gave better results.