Besides rainforests, there are over of mangroves in Malaysia, and a large amount of peat forest. Coastal land of the peninsula is fringed by mangroves, which cause sediment build up resulting in peat bogs. These provide a base for plants that can tolerate the conditions. The peat forests of coastal Malaysia provide an important habitat for waterbirds and fish. The dipterocarps that occur in the peat forest obscure the ground, limiting ground vegetation. At higher altitudes, oaks, chestnuts, and rhododendrons replace dipterocarps.