Relating leaf area index of natural eucalypt vegetation to climate variables in southern Australia

We address a need for a rapid technique to estimate the leaf area index (LAI) of pre-existing natural vegetation. This is required to determine the effects of agroforestry plantings on deep drainage from agricultural land. Previous work shows: (1) a relationship between the hydrologic 'footprint' of tree belts and their lineal leaf area (leaf area per metre of belt, LLA, m(2) m(-1)), relative to the LAI of natural vegetation and (2) that the LAI of natural vegetation is related to plant-available soil moisture and climate. We evaluated relationships between LAI measured at 37 sites across southern Australia and (1) annual average rainfall, P; (2) annual average pan evaporation, EO; (3)'available rainfall'-annual average rainfall, P, minus annual average pan evaporation, EO; (4) a climate wetness index P/E-0; (5) Specht's soil evaporative index, k = 0.0045 + 71.57/E-0. P was the best indicator for the data set used, i.e. LAI = 0.003P + 0.41 (r(2) = 0.80). Crown Copyright (c) 2008 Published by Elsevier B.V. All rights reserved.