Since lower caves levels are frequently full of exposed lava, especially if Yung's Better Caves is also installed, large scale fire spreading across cave can cause serious lag. I propose to replace Vanilla vines and leaves on the lower levels of caves system with some new fire-proof analogues. Alternative solution might include removing vines and leaves from lower levels all together.

Make all burnable greenery below like y 33 get a grey tint and get the "petrified" tag, With that tag it acts like stone, and when broken drops stone.