Many areas of the earth have been modified by humans but large areas of natural vegetation still exist in more inaccessible areas. The life form of a plant refers to its physical structure, size and shape. Lifeforms include trees, shrubs, lianas and herbs. Habitat refers to the conditions of slope, water drainage, and soil type that influence the vegetation cover. Water availability is one of the most important factors influencing plant growth.
Xerophytes are plants adapted to dry conditions.
Temperature affects physiological processes in plants. Plants have a temperature range within which they can survive as well as optimum temperatures for each of their functions. Ecological succession is a development sequence in which plant communities succeed one another as they progress to a stable climax, the most complex community of organisms possible in an area. Succession starts with pioneer species that can survive in harsh conditions. These pioneers moderate the harsh conditions and gradually other species move in.