| |
CRC PUBLICATIONS |
Estimating Leaf Area Index From Stem Diameter Measurements in Mountain Ash Forest
Fred Watson,
Rob Vertessy
Publication Type:
Technical Report
This is a publication of the initial CRC for Catchment Hydrology
CRC Program:
Forest Hydrology (Previous CRC)
|
Publication Keywords:
Modelling (Hydrological)
Forests
Trees
Leaves (of Plants)
Stalks
Eucalyptus regnans
Determination
Water Yields
|
Abstract / Summary:
Abstract
A model is presented enabling the prediction of the leaf area of an individual Mountain Ash ( Eucalyptus regnans ) tree given both the diameter at breast height (DBH) of the tree and the mean 1n (DBH) of all trees in the stand from which the tree came. The model was calibrated using linear regressions on natural log data obtained through destructive measurement of the leaf areas of 78 trees.
Predictions of the leaf area of individual trees and of the total leaf of a sample of trees were tested using destructive leaf area measurements from a further 88 trees. Tests of individual predictions showed that the model was able to accurately reproduce the dominant patterns of intra-stand variability in leaf area. Tests of total leaf area predictions revealed that the model could predict the leaf area index (LAI) of stands with errors ranging from 10% to 32% for trees younger than 60 years old, to a maximum of 88% for old-growth trees (225 years old).
The model was applied to a database of 2079 DBH measurements from 19 Mountain Ash stands. This application proceeded in two ways. Firstly, in a direct application of the model, individual tree leaf area predictions were made from each of the 2079 DBH measurements, and summed over respective stand areas to give LAI predictions for the 17 stands. When plotted against stand age adn adjusted for variations in stocking rate, LAI predictions followed an expected pattern peaking at just under 4 metres squared / metres squared for 10 to 20 year old forest and decreasing to less than 2 metres squared / metres squared for old-growth stands.
A more general application of the model was to anayltically combine the key model equation, predicting leaf area from DBH and mean 1n(DBH), with regression equations describing age-related variation in the stem diameters of Mountain Ash forest. In particular the variation with age of mean stand In(DBH), intra-stand distribution of DBH, and stocking rage were characterised. The combination of these equations produced an equation relating LAI to stand age which predicted a similar pattern of variation with age to the direct LAI predictions. This equation provided continuous estimates of LAI over a wide range of ages of Mountain Ash forest.
This report is available for downloading below. Printed copies can be purchased from the Centre Office.
 |
1 Download(s) |
|
|
|
|
|
|
|
|
Centre Office:
CRC for Catchment Hydrology
Dept of Civil Engineering
Building 60
Monash University Vic 3800
Tel: +61 3 9905 2704
Fax: +61 3 9905 5033
|
|
|
