Botany Photo of the Day

In a typical year, this Tasmanian snowgum looks like this, full of foliage and flowers. However, the harsh, extended cold of last winter killed most of the exposed living tissue. This left the tree covered in grey-brown dead leaves; for a few months, it looked dead. As you can see, though, the tree is recovering.

The effect of the cold replicated a phenomenon more often seen in Eucalyptus after a severe fire — regrowth from epicormic buds (i.e., buds within the bark of the tree). The abstract from this paper, Epicormic strand structure in Angophora, Eucalyptus and Lophostemon (Myrtaceae) – implications for fire resistance and recovery by Burrows in 2002, summarizes the phenomenon tidily: “In most angiosperm trees dormant epicormic buds are present in the outer bark, a position where they could be killed by fire. By contrast, in eucalypts the greatest epicormic bud initiation potential is at the level of the vascular cambium, which is protected by the maximum bark thickness. This might explain the pronounced ability of eucalypts to produce bole and branch epicormic shoots after moderate to intense fire.” I'll repeat myself and append “or moderate to severe cold”.

I don't know how many years will be required before the plant flowers again, but it seems to be on the road to recovery. In contrast, a number of younger plants of other species of Eucalyptus in the Alpine Garden did not have thick enough bark to withstand the cold. I believe the dead plants are slated for removal.