Just like animals, plants compete with each other for space and territory, though most have only a limited ability to retaliate against some asshole fern setting up camp on their lawn. But when it comes to protecting their territory, eucalyptus trees have a scorched earth policy -- they not only are immune to forest fires, but also actively encourage them.
You see, the eucalyptus itself is designed specifically to be the only tree standing after a fiery apocalypse -- they have stems hidden deep inside their trunks, ready to spring out once the smoke clears. So it basically spends its life throwing around gasoline, waiting for a spark.
"I love the smell of us in the morning."
And we're not exaggerating -- eucalyptus contains a kind of oil that is so flammable that the trees can actually explode when they catch fire, like someone uttering a one-liner before flicking a cigar into a gas station. The leaf litter from eucalyptus trees is so full of toxic napalm that bugs and fungus don't break it down -- it just dries out and covers the ground like a super-flammable carpet. If that weren't enough, the trees produce a bluish-gray cloud of evaporated gas that can go up like a fireball with one lightning bolt or thoughtlessly discarded cigarette butt.