You should add an exotic mob that can help the player get past one of the most difficult terrains of any biome.
The dragonfly would be a passive, giant bug mob. It cannot be tamed, but the player can mount and control it if they sneak up on it with bait. They will only be able to ride them for a short time within the biome or within a related set of coordinates set into the dragonfly's data. The bait could be spider eyes, and fermented spider eyes could actually draw them towards the player. Dragonflies could make nests of eggs in the treetops of their own accord to hatch new dragonflies.