USA — An iconic eucalypt tree growing in many areas burnt out in Victorias Black Saturday fires is better at re-sprouting after fire than first thought, according to senior botanist at Charles Sturt University (CSU), Dr Geoff Burrows.
A CSU research team consisting of Burrows, David Waters and Dr John Harper found the Mountain Ash can grow back from special buds under its bark like most other eucalypts, as well as from seedlings that grow from seed in the ash covering the ground after a bushfire.
“The Mountain Ash or Swamp Gum, with the scientific name Eucalyptus regnans, is known as a fire-sensitive eucalypt that does not regenerate well after a serious bushfire,” says Burrows.
“In high intensity fires such as those seen on Black Saturday, the tree is killed and doesnt re-sprout from the base or the branches like almost all other eucalypts. Mountain Ash usually regenerate as fast-growing seedlings. This results in forests of Mountain Ash that are all the same size and age.
“Recently, however, scientists have found Mountain Ash forests with mixed aged trees, indicating older trees here had probably survived less intense fires, re-sprouted from stems and branches and continued to grow, along with seedlings.”
Forests of Mountain Ash are found in the hills and mountains of Southern Victoria and Tasmania, now mainly in national parks and state forests. The Mountain Ash is reputedly the worlds tallest flowering plant, growing to a height of 100m.
Mountain Ash put most of their energy into growing tall as seedlings, leading to slender saplings and trees and only grow thicker bark at their base later in life.
“We previously found that other eucalypts had unique fire-protected bud-forming structures deep in their bark. Other researchers had suggested that Mountain Ash was such a poor re-sprouter because it didnt have any buds in its stems and branches,” Burrows says.