If you’ve ever been bushwalking in Australia you will have surely come across the damage caused by fire, whether it be the result of controlled burning or wildfire. In most cases the damage would have been relatively minor in comparison to that caused by the Black Saturday bushfires on 7 February 2009. The largest of the many fires burning on the day was the Kinglake complex, formed as the south-westerly wind change merged the Kilmore East (caused by fallen powerlines) and Murrindindi Mill fires. These fires were intensely hot; Melbourne had been suffering a heatwave having recorded three consecutive days above 43 degrees. On the 7th, temperatures peaked at 46 degrees with 100+ km/h winds from the north-west.
Small sections of the Kinglake National Park have been re-opened for public access, eight months after these fires destroyed 98% of it, including the office and most visitor facilities. Unlike the wildlife of the area, the trees didn’t have the opportunity to attempt escape but have however adapted to survive such an event. As featured in these photographs, the eucalypts have epicormic buds buried deep within their trunks. During normal growth, epicormic buds are inhibited from sprouting by hormones produced in leaves of the crown. If a fire is intense enough to remove all the leaves, the hormonal influence disappears triggering the epicormic buds to sprout thereby covering the entire tree in a new gown of leaves and branches. In a severe fire, the crown may be detroyed and even the epicormic buds on the smaller branches may be killed so the plant can only recover from the epicormic buds present on the main trunk.
Similar behaviour is exhibited by the grass-tree (Xanthorrhoea) with regards to its flowering being stimulated by fire. The fine example shown above has recovered to a flowering stage while the surrounding vegetation is struggling to make do in the seemingly now sterile topsoil. The dense and inflammable foliage surrounding the stem protect the apex of Xanthorrhoea from fire. Even though the trunk grows only a few centimetres in height per year, fire triggers rapid growth of the main shoot tip into a flowering spike. The spike grows at an average of 4 cm per day, attaining a maximum height of around 3 m in about 75 days.
Very informative and well researched post Cain – Well done ! I like the second image the best – nice work :)
i started off with two questions i didn’t know the answer to, i suppose i had them formed before i took the shots – why do trees grow shoots all over their trunks after bushfire and how fast does the flowering spike from grass trees grow? i have a grass tree on the decking at home that was purchased when it had a flower but it has never flowered since. my brother said you have to burn it to get it to happen but that sounds risky! it would have been nice to include a banksia and its exploding seed pods but i couldn’t find any at the time, didn’t know where to look. thanks Tony
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I like that second shot Cain ! Do you happen to know or have researched what that moss/vibrant green ground cover is ? I noted it grew in a number of the major fire areas in some capacity… interesting…
cheers,
the three shots were taken relatively close together – as you can see some ground areas are void of what i assume to be a moss and some are completely covered. i did a bit of a search but i didn’t take a close-up photo of it so have nothing to compare against. i’ll have to see if my brother knows
That would be great Cain – I think it’s pretty interesting that this vibrant green mossy plant came up first and in many cases seems to be still the only ground cover. Although it now appears to be dying off in the areas that I have recently seen.
cheers,
found a post the other day by Karl von Moller featuring the ground cover:
Forest regrowth in Daylesford 7 months later!