Soon you will reach some tree stumps. Jump between the first four. At the fifth you need to snap the stick supporting a spiky tree ahead. Immediately jump back left to avoid it falling. Use this to cross to the next jump. Having landed on the next tree, it will begin to fall, and you need to jump off quite late to avoid getting impaled on the trunk.
Once you jump to the low, thin stump, a boulder will come swinging towards you. Jump directly up to avoid it.
Jump over the boulder.
Continue to the next tree and down the slope, jumping the spikes at the bottom. Head right and you will reach an artificial spider leg. It is controlled by some of the other characters, but it is easy to avoid its attacks. Head underneath it once the leg is raised, and jump over the watery pit. After a few seconds walking to the right, a flaming tyre will be thrown at you. Move back over the pit to get it out of the equation.
Head right again and a flaming boulder will come rolling. You can jump over this one (jump straight up to ensure you get enough height), and should immediately run to the right under the ledge ahead to avoid another tyre. Climb the two sets of ladders, beginning with the first to the right in the cave.