© 1995 Heron Publishing—Victoria, Canada
Relationships between stem diameter, sapwood area, leaf area and transpiration in a young mountain ash forest
R. A. Vertessy (1, 4), R. G. Benyon (2, 4), S. K. O'Sullivan (3, 4) and P. R. Gribben (3, 4)
1. CSIRO Division of Water Resources, GPO Box 1666, Canberra, ACT 2601, Australia / 2. Melbourne Water, Box 4342, Melbourne, Victoria 3001, Australia / 3. Monash University, Wellington Road, Clayton, Victoria 3168, Australia / 4. Cooperative Research Center for Catchment Hydrology, Wellington Road, Clayton, Victoria 3168, Australia / Received October 20, 1994
Summary
We examined relationships between stem diameter, sapwood area, leaf area and transpiration in a 15-year-old mountain ash (Eucalyptus regnans F. Muell.) forest containing silver wattle (Acacia dealbata Link.) as a suppressed overstory species and mountain hickory (Acacia frigescens J.H. Willis) as an understory species. Stem diameter explained 93% of the variation in leaf area, 96% of the variation in
sapwood area and 88% of the variation in mean daily spring transpiration in 19 mountain ash trees. In seven silver wattle
trees, stem diameter explained 87% of the variation in sapwood area but was a poor predictor of the other variables. When
transpiration measurements from individual trees were scaled up to a plot basis, using stem diameter values for 164 mountain
ash trees and 124 silver wattle trees, mean daily spring transpiration rates of the two species were 2.3 and 0.6 mm day–1, respectively. The leaf area index of the plot was estimated directly by destructive sampling, and indirectly with an LAI-2000
plant canopy analyzer and by hemispherical canopy photography. All three methods gave similar results.
Keywords:
Acacia dealbata, Acacia frigescens, Eucalyptus regnans, heat pulse method, leaf area index, mountain hickory, silver wattle.
