Radiation-Vegetation Relationships in a 'Eucalyptus' Forest

Radiation-vegetation relationships for 12 species of 'Eucalyptus' from the south coast of New South Wales showed that the mean radiation values differed significantly between species. Confidence intervals around the mean radiation values, based on pooled standard deviation, were used as an index of species generality. There were differences in the size of the confidence intervals between species. While 'E. bosistoana' and 'E. maidenii' had large confidence intervals over all seasons, 'E. sieberi', 'E. muellerana', and 'E. globoidea' had very small confidence intervals. The species also exhibit a shift in the relative positions of their confidence intervals according to season. Clearly, radiation data are an important variable for eucalypt species delineation, and may be included as an explanatory variable when modeling the distribution of eucalypts. Solar radiation was calculated for the different seasons of the year using a model developed within a geographic information system (GIS); the input to the model is simply a digital elevation model (DEM) and the latitude of the site.