Other Forest Types
Hill dipterocarp forest:
This is very similar to the lowland dipterocarp forest formation and usually occurs on hilly terrain above 300m to 800m above sea level. A large percentage of lowland flora also grows here but again, this forest type has quite a number of tree and plant species that don't grow lower down.
In Peninsular Malaysia, a characteristic tree of hill forest is the seraya (Shorea curtisii) with their silver grey crowns dominating ridge crests. It usually grows in groves (an uncommon feature in rain forests) and tolerates dry conditions quite well.
This dipterocarp tree attains huge size and the thorny bertam palm (Eugeissona tristis) is often associated with it, growing in dense groves around the bases of the trees.
Lower montane forest:
Lower montane forest occurs above 800m to about 1500m above sea level; however, in small mountains or hills near the sea, the limit is much lower. The montane forest from 800m - 1200m is also called upper hill dipterocarp forest because of a certain number of dipterocarp trees that dominate the forest canopy, of which the tall dipterocarp Shorea platyclados is emminent.
All the lowland/hill dipterocarp trees have long since disappeared by the time you ascend to the montane forest because they don't grow in the moister and cooler conditions here.
S. platyclados and the other dipterocarps themselves drop out upwards at about 1200m to be replaced by lower montane oak forest dominated by trees from the Fagaceae and Lauraceae families. This montane forest is very dense and has a lower canopy height (15-30m) and few small emergant trees.
It's cool and scenic here. Clouds often develop during the day, smothering the forest and providing a good environment for mosses and epiphytes to thrive. Two good places from which to start your exploration of this forest are Fraser's Hill and Cameron Highlands, two hill resort centres in Peninsular Malaysia.
Upper montane forest:
This low stature forest (canopy height of 1.5 - 18m) is found on mountain peaks in Malaysia that tower above 1500m. It is also found at much lower elevations on small mountains near the coast, because of a weather effect known as the Massenerhebung heating effect with the temperature lapse rate lowest on the biggest mountain ranges and highest on the smallest mountains.
This means the increase with elevation of coolness and moisture is lowest in the big mountains and highest in the small mountains, especially those near the coast. Therefore, at a given elevation, small mountains are as cold as a large mountain higher up.
Conditions here promote the growth of specialized trees that are twisted and bent, with flattish crowns. Many trees are swathed in thick layers of moss, orchids, and filmy ferns. Clouds often cloak this forest, so much so that it's also called cloud forest or mossy forest, because of the abundance of mosses here.
Pitcher plants thrive here, and Malaysia is indeed the centre of pitcher plant and orchid diversity. Gunung Kinabalu in Sabah probably has half of the orchid diversity of Borneo and many species of pitcher plants too.
Peat swamp forest:
This forest type grows on peat deposited some thousands of years ago near the coast. Peat is vegetable matter that is only slowly decaying. The peat is usually 0.5 to 200m deep and supports a tall forest that is usually about 40m tall.
The peat layer is thick and usually dome-shaped. The forest are more or less entirely dependent on rain as their water source. Therefore, in drought they sometimes catch fire. In 1997, many of the peat forests in SE Asia caught fire because they had been heavily logged and drained prior to the severe drought that hit the region in that year.
This forest is best developed in Sarawak and Brunei, where several subtypes can be identified. Drainage is poor and the understory contains many pandans. Palms are uncommon; the sealing wax palm (Cyrtostachys renda) being the exception. Because of its striking colouration on its trunk, this palm is often planted in gardens.
Many animal species from the surrounding lowland dipterocarp forests are found here too. Peat swamp forests are very valuable for timber and most have been exploited. In the Peninsular, peat swamp forests can be viewed at the Paya Indah Wetlands Sanctuary. In Sarawak, virgin peat swamp forests are found at the Loagan Bunut National Park.
Mangrove forests grow near the coast and are periodically inundated by sea water. The main characteristic of mangrove forests is the stilt-like roots of most of the trees and it is usually dominated by a few species such as Rhizophora spp, Avicennia spp, and Bruguiera spp. Nipah palms are very common, forming dense thickets along the waterways. Mangrove forests are the habitat of numerous species of clams, snails, oysters, crabs, prawns, and fish.
Coastal fisheries depend on them, and they provide man with timber for firewood and charcoal, and poles for piling and scaffolding. Unfortunately, mangrove forests are often viewed as "wasteland" and much mangrove forest have been lost to provide land for industry and settlement, as well as clear felled for chips.
In the Peninsular, the most significant protected area of mangrove forest is the Matang Mangrove Forest Reserve (40,000ha). A small area of mangrove forest can be visited at the Kuala Selangor Nature Park. In Sarawak, mangrove forests can be viewed at Samunsam Wildlife Sanctuary.
Heath forest grows on soils which are high in silica, and therefore poor in nutrients, and highly acidic. The canopy is low, uniform, and usually densely closed with no trace of layering. Single emergants may occur here and there, but they are not of great height.
Under the most favourable conditions (the soil being relatively richer), they are similar in appearance to evergreen rain forest; dipterocarps are prominent among the larger trees, the emergants stand out about 27-31m high, and palms are common in the understory. At the other extreme, the canopy is only 4.5-9m and the overall diversity is much less.
The streams draining areas of heath forest are tea-coloured by transmitted light, and opaque black by reflected light owing to the presence of organic colloid minerals, acidic, and low in oxygen. More trees have small leaves than in evergreen rain forests, epiphytes are frequent and pitcher plants common in the open places.
Heath forest (or kerangas as it is known in Sarawak) is common in Borneo. Many of the National Parks in Sarawak contain at least some heath forest. In the Peninsular, heath forest can be most easily seen at various locations in the Endau-Rompin National Park. Elsewhere, they are rather rare. In Sarawak, heath forest is common; the best place to see them is at the Bako National Park, where a variety of heath forest occurs.
Fresh water swamp forest:
Freshwater swamp forest is forest that grows on low-lying land and is regularly to occasionally flooded with mineral-rich, fairly acidic water. Freshwater swamp forest varies from a low scrub with scattered 20-30m tall trees to a forest similar in structure to peat swamp forest. The ground level usually has a lot of spiny pandans, rattans, and palms.
In Peninsular Malaysia and throughout SE Asia, they used to be extensive, covering large areas along the lower river basins; now most are gone. They can be seen at Tasik (Lake) Bera and Tasik Cini (both in Pahang State). In Sarawak, some are conserved at the Samunsam Wildlife Sanctuary and in Sabah, the Kinabatangan Wildlife Sanctuary has relatively large areas.