11-25-2018
From SeanKroll "is it about correct that stand-replacing bush fires wipe out eucs with a fire-return interval of about 80 years on average, so eucs haven't evolved a lot of CODIT capacity, as fire doesn't care about decay-stopping chemicals?"
I can't really answer your question but I'll give my understanding. E. regnans (mountain ash) and E. delegatensis (alpine ash) are fire dependant species. They are there because of fire. Cool fires reduce ground material. Hot fires raise them to the ground. Wet gullies and slopes are less affected by the fire especially south and East facing. In very wet gullies especially up high it gives rise to non fire dependant ecosystems. They are essentially pockets of rainforest. The vague boundaries between them ebb and flow depending on the vigour of fire or extended wet. These sections are taped out of our coupe and not to be logged or burnt.
We recognise the age of the bush from the fire that created it. 1939 was the very big fire, before that 26, 08 and one in the late 1890's. I can sometimes be felling 39 and strike a pocket of 26. It is that obvious. Since 39 the larger fires were 68, 83 and 09. There are many more fires throughout these times so it is difficult to place a time span on the cycle of fire.
There are still some sections of mature ash forests and I took Gerry up to have a look. We have seen the best of them and they are ready to burn when the time is right. I was part of the filming crew for BBC at Wallaby Creek. One tree I climbed was 150' to the first dead peg and still about 6' diameter at that point. Logging those trees was stopped some time ago. The shame is that they burnt in 09. I don’t suggest logging them all but it seemed a terrible waste of timber. It was always going to burn just a matter of when.
Back to your question, being fire dependant I wonder if cool fires are in fact an important mechanism that exploits defect to the improvement of the gene pool. We may need to consider where CODIT fits in.
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