Fire, climate change and the unchallenged die-back theory

Recent calls to cull koalas on the north coast due to disease, raise the question about the level of stress koalas are under the factors contributing to it. The idea is to ‘humanely euthanize’ sick koalas, so they are not passing on chlamydia to others.This could lead to an increased number of healthier koalas, if other factors aren’t at play.

Co-incidentally, the proposal was followed by another article about Manna gum die-back on the Monaro and more on Vic Jurskis new book ‘Firestick ecology‘, referred to in the die-back article.

Interestingly, researchers looking into Monaro die-back have found ” . . . absence or presence of recent fire or pasture improvement made no difference to the trees’ health.”

While there is no doubt Aboriginals used fire in grassy environments, Vic’s theory requires pre-european inhabitants to burn every where.On this occasion, die-back on the eastern side Murrabrine Mountain, between Quaama and Cobargo, was one of Vic’s examples of how things have changed, due to a lack of burning and grazing.

Formerly part of Murrabrine State Forest, the mountain and the rest of the state forest were transferred to Wadbilliga National Park in 1999. At this point it’s worth noting that this was only a year after the first extensive canopy die-back event in the Bio-region, during the El nino in 1998. Not sure if Vic refers to this in his book though.

The only reason it was State Forest is due to the size of the trees, further to the west in Wadbilliga where soils are shallower, trees become smaller. Despite this desirability, the area was never logged, because it is generally too steep, as indicated in the map of slope classes below.

murrabslp2 Based on historic observations, the lack of grass, kangaroos and steep slopes suggest it is unlikely that much hunting would have taken place. Vic also suggested forestry would have leased the area for grazing, although again the steep slopes and lack of grass would seem to rule that out.

According to the recent fire history for the area, any Aboriginal burning would have ceased over 150 years ago, most of the eastern side of the mountain was burned in a wildfire during 1980. A fuel reduction burn was undertaken over most of the eastern side in 1990 and areas within this were burned again during 2003.

Much of eastern side of the mountain is in the Narira Creek catchment, of which close to 70% has been cleared. It seems likely that the focus of aboriginal grass burning for kangaroo hunting, would have been the more gentle slopes, on the now cleared land around much of the mountain.

In addition and for many sensible reasons, Aboriginal interests in the region were mainly focused on seaside activities. Mountains invariably have cultural significance and are frequently considered to contain scared places.

While forestry has its theory, their regulators, the EPA/OEH calamity prefer the climate change theory, so everyone is responsible and change is not necessary. They both can’t be right and until the loss of  biodiversity, as agreed by all governments,  is ruled out of creating problems for  forests and koalas, the differences of opinion will remain.

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