The Australian summer of 2019/20 has brought an unprecedented number of bush fires and at the time of writing more than 12 million hectares of bush and forests have burned. Shockingly over one billion animals have perished potentially wiping out whole species of native wildlife while reducing the habitat and food. While bush fires in Australia is a normal and regular occurrence during the hotter months, it is the huge scale of loss that has shocked the world.
The good news is that the land and trees can regenerate over time. There are many trees and shrubs that use a variety of ingenious methods to protect themselves and regenerate. In fact, some species of trees require the heat from fire in order for their seeds which are sealed with resin to melt it and sprout. Other species require the chemical signals in smoke to awaken seeds from dormancy and others rely on the tree’s underground structures for regrowth.
A good example of an Australian native tree that can regrow and thrive after being burnt in a bush fire are several species of Eucalyptus. The Euclyptus is a genus of over seven hundred flowering trees in the Myrtaceae family. These famous Koala food friendly trees have differing methods to enable regeneration depending on the species. The Eucalypt species that grow a rough bark such as Eucalyptus obliqua and Eucalyptus macrorhyncha have dormant epicormic buds that are burrowed and protected underneath the tree’s bark, when the bark burns and the foliage is removed the buds emerge to produce new branches and leaves.
There are other species of eucalypts that can regenerate from large roots underneath the tree which can sprout new growth, these are known as lignotubers. When a bush fire occurs, it may severely damage the above-ground part of the tree which often will not survive the fire, however, the lignotuber and root-system remains alive and well underground. It is important that these trees should be left alone as their removal will damage the lignotubes and may prevent the tree from successful regrowth. Lignotubers will thrive again given time and provide much needed food and habitat for wildlife in the area who have been affected by the fires.
Other smooth barked eucalypt species such as Eucalyptus regnans are often unable to withstand the heat and survive a bushfire but they have also evolved to provide a means to regenerate and ensure the survival of the species producing serontinous fruits. The gum nuts (woody fruits) contain seed and chaff which are activated by the heat and released. Once conditions are favourable for their survival they will germinate, and new trees will grow.
Other trees have developed fantastic ways to protect themselves from fire. Species such as Larches, Giant Sequoias and Grass Trees have extremely thick and fire-retardant bark which will burn but not through to the essential tissue below. Grass trees also insulate by retaining dead leaves around their stems. Other trees have moist tissues that protect against dehydration and also insulate against the heat of the fire.
A number of Pine and Eucalyptus tree species are able to keep fire damage to a minimum by growing a long trunk and tall crown so that fire does not reach the leaves and vital growth tissues and will even ‘self- prune’ dead branches to remove possible fire fuel.
If you see a tree flowering shortly after a bush fire, it is likely it is a fire stimulated species which will emerge quickly from the post-fire soil seed bank, creating a beautiful landscape of flowers and life.
For all your Tree Care needs, call Heritage Tree Care on 0737155444 or email firstname.lastname@example.org for a free, no-obligation quote, our qualified Arborists will be delighted to advise you on the best course of action for your trees and property protection. We cover Brisbane, Logan, Ipswich, Redlands, Toowoomba and Gold Coast area in Queensland, Australia.