Tuesday, Dec 10, 2013 at 20:24
Hullo mikehzz
This is a huge and complex subject, with no clear one approach "answer". So just a few points to consider.
It is interesting that you used the term "parkland". The most common descriptor used by white
explorers as they traversed this country back in the 18th and 19th centuries and reproduced in sketches and paintings was parkland - in many cases for as far as the eye could see, grasslands with large trees
well spaced throughout. How could this be? Because of the systematic and intelligent use of fire by the custodians at the time. [Ref "The biggest estate on earth" by Bill Gamage]
When the widespread use of controlled fire ceased and where the land was not used for cropping, the balance of plants and animals was upset and in many cases a thick understory developed. The fuel created as a result meant that fires started by lightning became much hotter and thus further altered the balance, in some cases causing the end of species in that area and enhancing the growth of others [plant and animal]. It is too early to know what the new balance will be, given the short time scale involved.
In the high country, the cattlemen often moved in after the original custodians and in many cases, continued with the use of patchwork fires in autumn, thus maintaining a generally clearer forest with less understory. The creation of NPs with little or no frequent cold burning has meant that a vigorous understory has developed. The result has been the recent series of devastating and frequent hot wildfires that have swept through some parts of the NPs. This new growth is no more "natural" than the previous growth of generally open forest.
Now some people might think that a landscape that is deliberately and systematically modified by man is not "natural". It could argued that man is an integral part of the natural environment, one of a number that modify the environment, for example, beavers which cut down trees, build dams, etc? I am sure biologists could think of many examples.
Now cattle grazing by itself will not solve the problem of devastating wild fires. And I would never advocate the wholesale grazing of the high country. What it might
well do is help keep the fuel loads down in selected areas such as the Wonnangatta Valley and progressively those areas where frequent cold burning might eventually lead to the re-establishment of more open treed [parkland] areas covered with native grasses.
In closing, I think it is hard to directly apply ones experiences in one part of the country to another. For example, my understanding is that the vegetation, topography, micro climate, etc of the Blue Mountains is generally not the same as that in the High Country.
Leaf litter in a forest with little or no understory can actually assist in the promulgation of cold fires in the right conditions. OTOH, high levels of understory fuel, together with high temps, low humidity and high wind speeds turn ground fires into hot crown fires with devastating impact on large mature trees.
Cheers
Andrew
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