The dipterocarp forests of Sabah in Malaysian Borneo are home to some of the world’s tallest trees, with some Shorea species reaching over eighty meters in height. This scene, from the lower elevations of the nearly undisturbed Maliau Basin, is what we may imagine when thinking of pristine mature forests – immense cylindrical boles reaching skyward, scattered throughout an open understorey.
But the landscapes of Malaysian Borneo are not all like this one. Some of the country looks hardly like a forest at all. The trees are all gone. Their immense trunks are too attractive and easy a target for logging. Paper, plywood, and the export market for hardwoods supply the demand.
The result is large-scale deforestation. Modern techniques emphasize selective removal of the largest and most valuable trees, and sometimes preserve riverside buffers, but there is no escaping the heavy impact of logging. Steep slopes and easily crumbled soils make the problem worse.
Even in selectively logged forests like the one we are working in below, something feels wrong. Some things are missing, and new things appear in their place.
For me one of the most noticeable differences is the presence of large gaps in the canopy. Forests are naturally dynamic environments where large trees fall and expose sunlit areas in which regeneration occurs. But in these heavily logged forests, the default instead becomes large clearings of dozens of meters, brutally hot, choked by tangles of thorny lianas and spiny palms, sometimes more than two meters deep, only passable by hacking a way through with a parang. The environment is no longer friendly.
One of the other most noticeable differences is the sound of the forest. In an undisturbed forest I expect the songs of birds, the calls of monkeys, and the rustling of leaves caused by all other manner of creatures. In a heavily logged forest, the canopy goes silent, but the air comes alive with the heavy rumbling of diesel engines cutting trunks, moving timbers onto tractors, and then hauling them away. A symphony of dust.
Almost eighty percent of land in Sabah has been impacted by high-impact logging or clearing in the last two decades (Bryan et al. 2013), and virgin forest within commercial forest reserves has declined by over 90% since 1970 (McMorrow & Talip 2001). This dramatic loss of forest cover has paralleled the state’s rapid economic development and diversification (timber revenue is largely retained by the state, while oil revenue primarily goes to the Malaysian federal government), and has so potentially played an important role in lifting many out of poverty. Ceasing the economic exploitation of forests would be bad in far different ways than current usage is bad.
Yet at the same time, much of the landscape feels far more like a mining operation than a sustainable forestry operation. Rates of extraction are often too high for the regeneration rates that can be sustained, and the highly disturbed forests that remain will be incapable of producing much economic value for many decades to come. As such, overall timber production has decreased sharply in the past decade (Reynolds et al. 2011). Current conservation efforts and broader implementation of reduced impact logging may help shift the situation towards a more sustainable direction, but I cannot help but wonder if the past decades of industry have done more to steal from the future than to help build it.
In collaboration with the state and the timber industry, much research is being carried out to understand the biological consequences of this disturbance. I play a small part in the BALI / SAFE (Stability of Altered Forest Ecosystems) projects aimed at addressing these questions. These data will provide a factual basis for thinking more carefully about these forests. But only personally experiencing these landscapes can shape how I feel about them. Something is missing, and I hope we will someday find it again.
