The region this took place is very bush fire prone and there were bush fires at the time.
Now from my own accounts after a bush fire, it's very common to go around and encounter big holes from where a dead tree has burnt out. In fact, sometimes these places cannot be ridden by offroad motorbike because there's too many large holes and a nasty accident is almost a given.
So the idea of locating such a hole to use as a grave is not out of the question and I am sure concealing it would not be that hard either. You could quite easily fill it in and even go as far as to transplant one of the native grass trees on top. These trees have the ability to survive bush fires and are abundant in the region from the few pictures I have seen of the forests.
Two grass-trees grow in Canadian Regional Park. Austral Grass-tree Xanthorhoea austalis is wide spread in the park with Small Grass-tree Xanthorhoea minor in a few areas. In some areas these two sp…
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Grasstree Burning
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Granted, the relocating of a grass tree may be a little difficult. So covering a hole with dirt and burnt timber would be a seemingly minimal effort and more likely option.