The atoll of the Cocos Keeling Islands has evolved in isolation from a continent through the forces of vulcanism, subsidence and coral growth. The highest point among the islands is currently less than 10m above sea level. Generally, the further an island is from a large land mass the fewer the numbers of species that are present.
The plant species that can be found on the islands today are the result of a long history of chance arrival and colonisation and the recent history of environmental modification. Due to the sandy soil conditions on the islands only certain plants are able to establish themselves while others fail. As a result of the once thriving copra industry on the Cocos Keeling Islands large scales of native forest were cleared so that stands of coconuts could be planted. The atoll is now lush with pisonia, rich green thickets of octopus bush and beach cabbage and a thick, dominating coconut forest.
The majoirty of the established plant life on the Cocos Keeling Islands grows well in sandy, rocky and exposed conditions. Due to the remoteness of the islands, locals have learned to value what is available to them. The beach almond or ketapang (terminalia catappa) seeds offer an edible, almond-like kernel that often washes up on the beaches. The hardwood of the pemphis acidula which can be found on the lagoon shore is used by locals to make knife handles and walking canes due to its resistance to rot and warping. Cordia subcordata or ironwood has been harvested extensively at the time of settlement for its strong, termite-resistant wood and is also an important seabird nesting tree. Other plants and trees such as the beach calophyllum (calophyllum inophyllum) also provide shelter and food for local and vagrant animal species. White terns favour the tree for its nesting possibilities while crabs enjoy its seeds.