Radiation-vegetation relationships for 12 species of Eucalyptus from the so
uth coast of New South Wales showed that the mean radiation values differed
significantly between species. Confidence intervals around the mean radiat
ion values, based on pooled standard deviation, were used as an index of sp
ecies generality. There were differences in the size of the confidence inte
rvals between species. While E. bosistoana and E. maidenii had large confid
ence intervals over all seasons, E. sieberi, E. muellerana, and E. globoide
a had very small confidence intervals. The species also exhibit a shift in
the relative positions of their confidence intervals according to season. C
learly, radiation data are an important variable for eucalypt species delin
eation, and may be included as an explanatory variable when modeling the di
stribution 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 t
o the model is simply a digital elevation model (DEM) and the latitude of t
he site.