Short Rotation Coppice (SRC)
SRC is an energy crop which usually consists of densely planted, high-yielding varieties of willow and poplar. Grant assistance is available to help plant the crops on a short rotation of 3-5 years for the production of biomass. These crops can yield 8 - 10 cubic metres of timber per year per hectare that can be harvested and chipped. These crops are harvested using specialist machinery not dissimilar to conventional agricultural combine harvesters. The coppice stools can remain productive for thirty years before they need to be replaced.
Planting SRC in place of conventional crops can increase farm diversification, reduce fertilizer and chemical inputs, improve biodiversity and add landscape amenity value. The most vigorous varieties of willow, if grown on a 5-6 year rotation can produce stems of 100 to 130 mm in diameter, which are suitable for cutting into logs. It is important that woodchips are dried before they are burnt.
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Woodchips, when produced from freshly felled trees can be up to 70% moisture. Whilst large boilers over 400kW output may be able to burn wet woodchips, smaller boilers need dry chips of a moisture content of 30% or less. Forest Research has carried out several trials on SRC and information is available at www.forestry.gov.uk/woodfuel.