ENVIRONMENTAL CREDENTIALS OF WOOD

Introduced by Dr Martin Ansell, University of Bath, on 24 October 1997

The presentation emphasised the sustainable nature of modern forest industries which convert
very nearly the whole tree into commercial products such as solid timber for roof trusses, wood chips and
strands for panel products, bark chips for horticulture and residues for fuel and chemicals. Forestry
practices are continually being refined to maximise wood yield through development of disease-resistant
and fast growing seed stock and effective forest management. At the same time the problems associated
with the felling of virgin forests in sensitive locations, bad clear-felling practices, the disruption of
ecological communities and the pollution of water courses are fast disappearing.
The microstructure of wood was examined to emphasise the concentric annual rings, to explain its
anisotropic mechanical properties and to differentiate between soft and hard woods. Forest practices in
various parts of Canada were reviewed and the improvement in them in Vancouver Island's temperate
rainforests noted.
The use of wood in wide-span structures using glue-laminates, laminated veneers or Parallam was
demonstrated and wind turbine blades using rotary cut veneer provide an excellent example of the
environmental credentials of wood by employing a sustainable material resource to capture energy from a
sustainable source, the wind.
During the discussion, the acceptance of timber-framed buildings was raised. Two-storey houses
are now more extensively constructed and testing of 4- and 5-storey buildings is in progress.
Tree farming to yield a crop within 10 years is being considered as a sustainable method of producing fuel.
Martin Ansell