New Guinea forests

Trees of the lowlands

Canopy trees can reach over 50 m and have straight trunks, which often are supported by buttress roots. Majestic in height and stature, they belong to the Pometia, Canarium, Cryptocarya, Terminalia, Anisoptera, Syzygium, Ficus, Celtis, Dysoxylum and Buchanania genera.
Click here to find out more about some of these species

The primitive Araucaria, a coniferous survivor of Gondwanaland, is the tallest tropical tree in the world and can be found mostly in scattered locations in isolated stands.

In eastern New Guinea, dipterocarps (tall trees with two-winged fruit) can cover large areas, in elevations up to around 500 m. Beyond that point, montane oak (Castanopsis acuminatissima) may form dense forests on ridge crests and upper slopes.

Dipterocarp trees, which account for a majority of the world’s trade in tropical hardwoods, are scarce in the lowland forests. Their relative absence is therefore a blessing for the area’s forests.²

Far below the canopy…

In the dim light of the lowland forest undergrowth, the absence of light keeps vegetation low. As in other tropical rainforests, the topsoil is so thin that trees need buttress roots to firmly anchor themselves to the ground.

At lower altitudes, tall palms are common, along with those in the shrub layer. Ferns, and tree and rattan seedlings are abundant, while woody lianas, fleshy climbers and climbing ferns are common. Climbing rattans are always present, but primarily thrive in forest openings. Epiphytes - mainly orchids and ferns - prefer the crowns of the canopy trees.

Montane forests

Beyond 1,000 m, the lowland forest gives way to montane forests. Here, the canopy is lower than the lowland forests and fewer trees rely on buttresses. Branches also grow lower on the trunks and the shrub layer is denser.

Montane forests do not have as many plant species as the lowlands. In fact, lowland species are poorly represented at higher altitudes, where they are replaced by beech (Fagaceae), laurels (Lauraceae), Elaeocarpuaceae, Cunoniaceae and conifers (Coniferae).

While palms, climbing rattans and woody lianas become rarer with altitude, other plants take dominance, such as epiphytic mosses, ferns and orchids.

Like lowland forests, montane forests are not uniform – based on the species composition and forest physiognomy, specialists divide them into lower montane, mid-montane and upper montane forest.

>Montane forests in slices

• Lower montane forests
• Mid-montane forests
• Upper montane forest