The majority of the large trees in Borneo’s rainforest are the dipterocarp trees which play a dominant role in the ecology of the forests. Dipterocarps reproduce in gregarious "mast" fruiting events which are visually spectacular and only occur every few years.

The “trigger” for such an event has been speculated to be a period of drought and sunspot activity. When such mast flowering occurs, the forest canopy is transformed into a brilliant mosaic of yellow, brown, orange and even purple, all in varying shades of colour. The dominant hypothesis for mast events is that predators are incapable of consuming so many mast seeds so that these species successfully germinate and continue to survive.

Dipterocarp literally means ‘two-winged’ fruits and they are the distinctive seeds that look a bit like a badminton shuttle-cock that you see on the forest floor. The ratio of fruit weight to the total wing area is much higher in dipterocarps than in most other winged fruits so they spin to the ground within a few metres of the parent tree.

Dipterocarps often reach heights of 50 metres or more and Sabah is considered to have the tallest tropical trees in the world, though there are very few of these large trees left. Dipterocarps are commercially valuable species.

Rainforest biodiversity and its value to us
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