More than 80% of Guyana is still covered by forests, those forest also contains the world's rarest orchids ranging from dry evergreen and seasonal forests to montane and lowland evergreen rain forests. These forests are home to more than a thousand species of trees. Guyana's tropical climate, unique geology, and relatively pristine ecosystems support extensive areas of species-rich rain forests and natural habitats with high levels of endemism. Approximately eight thousand species of plants occur in Guyana, half of which are found nowhere else.