In a few places the forest comes right down to the shore sea-cliffs but in most places the terraces close to the sea are colonised with salt-bush with its glossy light green leaves and small white flowers along with dense stands of Pandanus with its large pineapple-like fruit and saw-like leaves. This vegetation grows on a thin layer of soil covering the old coral reef limestone which was lifted out of the sea as the island was pushed upwards about 150,000 years ago.

Further inland the forest is a tropical jungle like many others with the exception that in many places the forest floor is clean as though swept by a caretaker and there are few vines to impede a walk through the jungle. It is not just the dense canopy limiting the amount of light that reaches the forest floor that prevents dense undergrowth forming, but the red crabs contribute by eating any seeds or small seedlings trying to grow.

The forest trees are often covered in orchids, colourful flowering trailing plants like Hoya and birds-nest ferns. Wherever you are in the jungle you will not be far from some unique species found only on Christmas Island. This could be a tree such as the Arenga Palm, an orchid like Ridley's orchid, one of the glow-in-the-dark mushrooms or the animals that live in the forest like the crabs, the small blue-tailed skinks (lizard), the small insectivorous pipistrelle bat or the larger fruit-eating bats.