Wood Processing
High quality timber is processed by sawmills for the
construction, furniture and other industries, and this processing
produces residues and co-product such as offcuts, bark and sawdust
that are potentially suitable woodfuel. Most of this material goes
to existing markets but some material, particularly from smaller
timber processers is being used to produce energy.
Sawdust from sawmills, especially dry sawdust from sawing kiln
dried timber, is potentially highly suitable for wood pellet
production. Small scale pellet presses designed to be used
alongside sawmill operations are available in the UK, and a
portable pellet press that can travel to sawmills with insufficient
capacity to justify a dedicated press may be another
alternative.
Tree surgery - Aboricultural Arisings
Tree surgery work from utilities operations and the maintenance
of municipal and domestic gardens and verges of roads and railways
can yield large quantities of arisings and residues that are
potentially suitable for biomass fuel.
In Scotland, the recent
Aboricultural Arisings Scotland Study
commissioned by Forestry Commission Scotland estimated that around
172,000 oven dried tonnes of woody material is produced in Scotland
each year by landscaping, tree surgery and forestry services
companies. Aound half of this is brash and half is heavy timber,
which has a number of uses from horse bedding to composting. Heavy
timber, which does not compost easily, is already being used for
bioenergy and some material may be suitable for local heat
markets.
Aboricultural arisings can have a high bark and therefore high
ash content when burnt. This may may make some of the
material unsuitable or undesirable for some systems, especially
domestic and small scale systems. They also require careful
screening for foreign particles such as stones and wire.
Is it Waste?
SEPA provides guidance on "What is Waste?" (
www.sepa.org.uk/waste/waste_regulation/is_it_waste.aspx).
Untreated wood such as sawmill slabwood and arboricultural arisings
are exempted from the Waste Incineration Directive
(WID), and can be handled in the same way as other virgin
wood.