Normally, a dog that had died in the wild would succumb to decay and be eaten by other foragers. However, as the dog had died inside a tree, it was unlikely that other animals could reach it – and, due to the height of the body, it was unlikely that other animals could smell it either.
Additionally, the kind of tree that the dog had lodged itself in was uniquely qualified to lend itself to the natural mummification process. Chestnut oaks contain tannins, which are used in taxidermy and tanning to treat animal pelts so that they don’t decay. The tannins from the inside of the tree seeped out into the dog and prevented it from rotting inside.