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The Forest Energy Programme has focused primarily on researching
wood fuel supply chains from first thinnings.
In 2009, there was an opportunity to carry out a preliminary
evaluation of wood fuel from residue bundles. A Timberjack
1490D slash bundler was contracted by Coillte to produce residue
bundles on a number of sites. Two types of bundles were characterised
- Sitka spruce lop and top from clearfelled areas and lodgepole
pine small whole trees from a checked stand.
The Wood Energy Research Group at Waterford Institute of
Technology (WIT)
sampled the bundle assortments and took measurements to quantify
parameters related to the energy content of the bundles. Bundle
green weight, moisture content, dry weight and bulk volume
were assessed. The net calorific value was estimated based
on the moisture content. The data collected may be used in
assessing the financial value of the bundled fuel, the productivity
of supply chain operations - in particular the road haulage
- and to quantify the fuel requirements of a particular scale
of end-user.
Collection of residues after clearfelling is becoming a standard
practice in European and North American forestry - to reduce
reforestation costs, cut down on fire hazard and generate
income from woodfuel sales. Several countries, including the
UK, have produced best practice guidelines identifying appropriate
sites for removing bundles and planning and implementing the
operation.
The perceived benefit of bundling residues is simply to compact
an otherwise bulky material and produce an assortment that
can be extracted by standard forwarder and transported by
road using standard timber trucks.
In an Irish context many questions remain -
- Can pre-preparation of the harvesting sites to accommodate
the bundling operation increase bundler productivity and
reduce production costs?
- Can wood fuel production from residues be more cost-effective
by terrain chipping or extracting loose and chipping at
forest roadside?
- Would residues benefit from summer seasoning on site prior
to bundling? - and
- Will green residues bundled from a fresh clearfell dry
in the bundle, or will the bundled residues decompose?
It is hoped that the Forest Energy Programme can answer some
of these questions in 2010.
For further information on the Forest Energy Programme, contact
Tom Kent, Waterford Institute of Technology - email: tkent@wit.ie
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