Widely hailed as a renewable natural resource, tropical timber from old-growth tropical forests is selectively logged worldwide at an unprecedented scale. But research now reveals that these sources of timber are far from sustainable and environmentally friendly.

Studies reveal that once prime tropical hardwoods – such as Brazilian cedars, ipe (Brazilian walnut), and rosewood – have been logged, they do not grow back to commercial levels and are at risk from disappearing altogether.

Slow growing and "commercially valuable" species of all kinds have been overexploited over the course of human history – just look at the whaling industry or fisheries. Yet many tropical timber species are still thought of as a renewable resource. We are only beginning to see over-exploitation parallels in tree species. Many high-value timber species are logged until their populations collapse altogether.

Timber harvests in Pará equate to almost half of all native forest roundlog production in Brazilian Amazonia – the largest old-growth tropical timber reserve controlled by any country. Brazil accounts for 85 percent of all native neotropical forest roundlog production. Researchers have found that loggers can no longer depend on areas where high-value species were formerly abundant to fetch high economic returns. This means that logging operations are continuously forced to extract timber trees from new areas of unlogged primary forests.

Even so-called ‘reduced-impact logging’ in tropical forests can rarely be defined as sustainable in terms of forest composition and dynamics in the aftermath of logging – never mind the greater susceptibility of logged forests to catastrophic fires. Environmental licensing and market certification of logging concessions need to take this into account, and review minimum preconditions in terms of volumetric quotas of roundlogs harvested per species and regeneration standards over multi-decade logging cycles.

After selective logging, there is no evidence that the composition of timber species and total forest value recovers beyond the first-cut. The most commercially-valuable timber species become predictably rare or economically extinct in old logging frontiers.

Only recent logging operations, which are furthest away from heavy-traffic roads, are the most selective, concentrating gross revenues on a few high-value species.

Managing yields of selectively-logged forests is crucial for the long-term integrity of forest biodiversity and financial viability of local industries.

Current commercial agreements could lead to ‘peak timber’ and then widespread economic extinctions across other tropical regions. We can already see a market shift, in which loggers in old depleted logging Amazonian frontiers are forced to depend on fast growing, soft-wood timber species.