Today is National Eucalypt Day. #NationalEucalyptDay.
There are more than 700 species of this tree, which are found in, and often dominate, most ecosystems across the continent. Most species of Eucalyptus are native to Australia. Many of them are under threat, from over clearing, over burning and climate change. One of those at risk is the Snow Gum, the ubiquitous tree of the mountains in the south east corner of the country.
Snow gums are the classic alpine tree of the mainland, generally growing at heights between 1,300 and 1,800 metres asl. But wildfire has been devastating large swathes of snow gum habitat, with significant fires in the Victorian High Country in 1998, 2002/3, 2006/7, 2013 and 2019/20. Much of Kosciuszko National Park was burnt in 2003 and 2019/20. South Eastern Australia suffered from a drought that lasted more than a decade and this has increased the severity of the fires that have occurred since the turn of the 21st century. It is estimated that the 2019-2020 bushfires impacted 462 km2 (33%) of mapped snow gum forest that regularly has seasonal snowpack.
The species regenerates from seed, by epicormic shoots below the bark, and from lignotubers. A lignotuber is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire.
After fire, the parent tree has been killed back to ground level, with subsequent re-shooting of leaves from epicormic shoots or lignotuber. In this way, individual trees can exist through various ‘lives’, often surviving multiple fires. However, more frequent fires is causing more death of trees.
‘We found that the lignotuber continued to re-sprout very well after one fire, but after two and three fires, the number of new sprouts significantly declined. The level of whole-tree death (that is, the stems and lignotuber dying) was fairly low following one and even two, fires; however, after three successive fires, on average half of all trees in our plots were dead. In some plots, this figure was as high as 80 per cent of all trees’. (source).
It is possible that repeated fire will lead to the localised loss of snow gum forest and woodland. They could convert to shrubby wastelands, possibly dominated by wattles. There are already areas across the Alps where the forests are starting to transition from Snow Gums to something else.
Are snow gums going to be lost to climate change?
The Victorian government is now so concerned about the threat of fire on Alpine Ash – another mountain tree species – that it has launched a seeding program to help the species survive.
As yet the government does not see the need to intervene in the same way with Snow Gums.
Who is tracking this issue? Who would make the call to intervene?
If you see loss of snow gums (conversion of snow gum woodland to scrub or wattle dominated woodlands), please report it here.
Research shows that to protect these forests, we need to reduce the frequency and intensity of fires in these communities.
To keep fire out of these systems, we need additional resources for ground and air fire fighting:
- a volunteer remote area firefighting team, as Tasmania and NSW already have,
- additional air resources – including a publicly owned air fleet, and
- additional remote area career fire fighters (to their credit, the Victorian government has increased the number of fire fighters in the last state budget).
Having extra resources means we can protect these forests from fire rather than having to focus on towns and other human assets during bad fire seasons.
Sadly, Snow Gums are also at risk from dieback, which is caused by a native beetle, but which appears to be made worse by the warming being driven by climate change.