Have you read Margaret Atwood's MaddAddam trilogy? It's one of my all-time favourite works of science fiction.

Human beings have the (rarely used) capacity to improve the quality and usability of our surroundings. If at some point in the future, we should collectively decide to rehabilitate this planet of ours, mutant poisonous kudzu and HIV-reservoir mosquitoes will not make the work any easier.

Fire is necessary for healthy forests. And although I am excited about the emerging prospects of genetic alteration I'm pretty sure it's not going to get as far as making carbon based lifeforms fireproof.