The Tasmanian snow gum, Eucalyptus coccifera Hook.f., forms low-open woodlands on the dolerite plateau of Mt Wellington, Tasmania. The species occurs at the inverted and upper slope tree-lines, and its spatial distribution appears to be strongly influenced by soil drainage characteristics. Both experimental work and field observations indicate that water-logging is the principal agent determining the inverted tree-line limits of E. coccifera on Mt Wellington. However, deficiencies of moisture also play a role in limiting the distribution of snow gums. There was no evidence to indicate that frost influences the lower tree-line limits of the species, despite the genetic variation shown in the frost resistance of trees from various provenances. Strong ice-bearing winds influenced the morphology of E. coccifera individuals, but was not a factor in limiting the distribution of the species.