Mixed Dipterocarp Forest

Description: Mixed dipterocarp forest is the richest of Sarawak's major forest types, the archetypal "tropical rainforest". Mixed dipterocarp forest is the most significant forest in Sarawak, both in terms of area covered and commercial importance for logging. Its name derives from the towering dipterocarp trees (Dipterocarpaceae) which dominate this forest type.

The canopy formed by these great trees can be as high as 60m, excluding most light from the forest floor. As a result, the forest floor (or "understory") can be quite open and easy to pass through. However, a number of plants specially adapted to low-light do grow on the forest floor, along with young canopy trees - trying to break through, or waiting for an old giant to topple, leaving enough of a gap (and sunlight) to fill.

Sarawak's mixed dipterocarp forest is amongst the most diverse on the planet, with up to 1500 tree species alone (compared with only about 175 tree species in the whole of North America, and 75 in Europe!) . In addition to the dipterocarps these forests contain a huge array of palms, fruit trees such as figs, durians and mangoes, ferns, orchids, liana vines, and numerous other plant types. Many of the large trees are literally covered in various other epiphytic and parasitic plants. The famous giant rafflesia flower is one type of parasitic plant found in mixed dipterocarp forests.

This huge diversity results in an extremely complex ecosystem, with species of plants and animals adapted to living at different levels in the canopy or on the forest floor, or only on certain trees (for example most fig trees are pollinated by their own unique associated species of wasp, not even found on other fig species!).

Another consequence of the huge diversity of tree species within mixed dipterocarp forests is that any single given species may be very rare (if there are 500 tree species found within 1 hectare, that means most of them only occur once in that area). Many of the plants found in Sarawak's mixed dipterocarp forests are only found in Borneo, some only in Sarawak, and some only in certain national parks within Sarawak.

The diversity of plants in mixed dipterocarp forests is also reflected in the diversity of animals, birds, and insects found there. For example, Sarawak has an estimated 185 mammal species, 530 bird species, and 154 snake species (don't worry - they're mostly harmless), plus more than 5000 beetle species, 3000 moth species, and 900 butterfly species! Many of these are found primarily in the rich dipterocarp forests.

Various subtypes of mixed dipterocarp forest have been described, including lowland dipterocarp forest, hill dipterocarp forest, summit ridge forest and submontane forest. However, these types are not all clear-cut, and the borders between dipterocarp forest types (and borders with other forest types as well) may be diffuse and not obvious.

Best places to see: Primary mixed dipterocarp forest can be seen at most of the national parks described in this website. Lambir Hills National Park has potentially the most diverse mixed dipterocarp rainforest in Sarawak, and possibly one of the most diverse forests in the world. It is also only a 1/2 hour drive from Sarawak's second city, Miri! The facilities there (including an observation tower) also make Lambir Hills one of the better places to see into the canopy itself. In the immediate vicinity of Kuching, the mixed dipterocarp forest of Gunung Santubong is hard to beat; and because part of the trail runs along a ridge it also allows a good opportunity to see into the canopy of the trees whose bases are far below. But for sheer size and the pristine condition of the forests, Mulu National Park and Batang Ai National Park are probably the richest remaining areas of mixed dipterocarp rainforest in Sarawak.