HABITATS AND VEGETATION TYPES
Malaysia is richly endowed with a variety of natural habitats. From sandy beaches to alpine forests, these habitats are conducive to plant growth and vegetation development. The country's tropical rainforests are categorized in 14 different forest formations, each one possessing a unique set of floristic characteristics and fulfilling specific ecological functions.
Climate is one factor, amongst others such as altitude, water table and water quality, rainfall and soil type, that determines the development and species distribution and composition of the forests. The Malaysian climate is wet and warm, with rainfall evenly distributed throughout the year. It is also strongly influenced by the winds that blow over the Indian Ocean in the southwest and the Pacific Ocean in the northeast. These wind systems are, respectively, the southern and northern monsoons. In most parts of the country, there is only a very short dry season, and the average temperature in the lowlands is 24–26 °C. Along the Malaysian–Thai border, however, a short but pronounced dry season is experienced annually, resulting in the development of semi-evergreen forest, where deciduous trees are present.
The quantity and quality of moisture in the soil is reflected in the location and distribution of dryland and wetland forests. Drylands comprise sandy beach and rocky shore vegetation and hill and mountain forests, whereas wetlands are made up of mangrove, freshwater and peatswamp forests. By far the most extensive dryland forest formation in Malaysia is the lowland and hill mixed dipterocarp forest. Up to 1990, this forest formation covered a total area of about 17.29 million hectares, but this has been considerably reduced as a result of conversion of forested land for other uses. Timber harvesting has also drastically altered the structure and floristic composition of this forest type.
Soil type greatly affects the vegetation that grows on it. Heath forest, for example, develops on highly acidic soil that is poor in base minerals. The Malaysian name given to heath forest, kerangas, is an Iban word that means 'land on which rice will not grow'. Ultramafic soil, on the other hand, is high in base metals and carries a distinct forest formation, which contains a high number of endemic plant species. On limestone, soil is hardly formed except in fissures and crevices and at the foot of slopes and tops of ridges, thus limiting the number of plant species that can thrive in this habitat.
As altitude increases and the atmosphere becomes cooler and moister, a shift from lowland to montane forest is observed. Montane forest is found in the highlands, in places such as Cameron Highlands and Fraser's Hill. Beyond the altitude of montane forests are subalpine and alpine forests, which occur in only one location in Malaysia—the spectacular Mount Kinabalu.
