It’s a cycle, the trees grow back

MEDICAL experts are lobbying the state government to stop climate change by ending native forest logging in Tasmania. It is claimed climate change is caused by carbon emissions, which, presumably, are coming only from native forest logging.

What is the evidence for carbon emissions from native forest logging? Native forests for timber production are managed under the sustained yield principle, which ensures the volume logged each year can be sustained indefinitely. The area logged each year is regenerated, so the whole area remains as forest. The area logged is regenerated most often by burning the debris left after logging, and sowing seed of the same species as before. The rotation cycle is about 100 years, so there are forests in different stages of growth and maturity, to support animals and birds.

Most wood produced from native forest logging is used in buildings, furniture, cabinet work and such uses where the wood does not decay and produce carbon emissions. Pulpwood for paper will eventually decay and produce emissions, but unless the logging is to produce only pulpwood the emissions are minor. The other source of carbon emissions comes from the residue burnt at regeneration, but again it is not from a huge amount of wood.

Trees sown at regeneration, after a slow start, soon grow rapidly and after a few years store a lot of carbon, replacing the deficit.

Carbon emissions from native forest logging must be compared with other activities. Use of concrete and steel in construction has huge emissions, estimated to contribute 8 per cent of global carbon emissions. It would be beneficial to substitute wood in construction.

John Walsh South Hobart