Letter: Letters: Green wood

From STEPHEN GUEST

I must, alas, take issue with one part of John Emsley’s analysis in
his piece ‘On being a bit less green’ (Forum, 17 October). He says human
activities generate carbon dioxide in five main ways. One of these, he says,
is ‘using wood’. Whoa! That depends how it’s used.

The carbon in wood fibre is already part of the atmospheric CO₂
cycle: the destruction of a tree cannot introduce any more CO₂
into the atmosphere than it has previously extracted from it. Trees simply
act as temporary carbon store or sink. This is in contrast to the burning
of fossil fuels, the carbon in which would not otherwise be available to
be added to the CO₂ already in the atmospheric cycle.

Clearly, the failure of humans to replace the trees they cut down reduces
the total size of the carbon store and this means more CO₂ actually
in the atmosphere (as distinct from the cycle). The overwhelming majority
of tree felling is done not because humans want to ‘use’ the wood, but because
they don’t. They want the land used by the trees so they can use it for
something else.

When it comes to using wood, the situation is different. If a tree is
milled into hard products such as construction and furniture timbers, the
product continues to function as the living tree did: as a carbon store.
Assuming logging involves allowing the continued existence of the forest
and that every tree felled is replaced by another, then ultimately an equilibrium
is reached.

Given that all the alternatives to using timber – bricks, cement, steel,
aluminium – are products which require the burning of fossil fuels in prodigious
volumes, the choice of timber whenever possible is the environmentally correct
one.

Stephen Guest Carlton Victoria, Australia