© 1996 Heron Publishing—Victoria, Canada
Long-term growth and water balance predictions for a mountain ash (Eucalyptus regnans) forest catchment subject to clear-felling and regeneration
R. A. Vertessy (1, 3), T. J. Hatton (1), R. G. Benyon (2, 3) and W. R. Dawes (1)
1. CSIRO Division of Water Resources, GPO Box 1666, Canberra, ACT 2601, Australia / 2. Melbourne Water, Box 4342, Melbourne, Victoria 3001, Australia / 3. Cooperative Research Center for Catchment Hydrology, Monash University, Clayton, Victoria, Australia / Received March 2, 1995
Summary
We used a physically based ecohydrological model to predict the water balance and growth responses of a mountain ash (Eucalyptus regnans F. Muell.) forest catchment to clear-felling and regeneration. The model, Topog-IRM, was applied to a 0.53 km2 catchment for a 3-year pretreatment period, and a 20-year period following clear-felling and reseeding of 78% of the catchment
area. Simulations were evaluated by comparing observed and predicted streamflows, rainfall interception and soil water values.
The model faithfully simulated observed temporal patterns of overstory live stem carbon gain and produced a leaf area trajectory
consistent with field observations. Cumulative throughfall was predicted within 1% of observations over an 18-year period.
Over a 4-year period, predicted soil water storage in the upper 1.5 m of soil agreed well with field observations. There was
fair correspondence between observed and predicted daily streamflows, and the model explained 76% of the variation in monthly
flows. Over the 23-year simulation period, the model overpredicted cumulative streamflow by 6%. We argue that there is a useful
role for physically based ecohydrological models in the management of mountain ash forest catchments that cannot be satisfied
by simple empirical approaches.
Keywords:
ecohydrology, forest growth, modeling, water yield.
