COFORD has recently published the new All Ireland Roundwood Production Forecast 2011-2028. The publication is based on the work of COFORD Roundwood Supply Group and is authored by Henry Phillips.
The report differentiates between potential standing volume (to 7 cm top diameter) and net realizable volume. Potential volume is the biological potential, while realizable volume is what can be expected to be available for wood processing, after harvesting losses and other factors have been considered.
Output of wood from forests is set to double over the period of the forecast, with almost all of the increase set to come from privately-owned forest in the Republic.
Forest (including post consumer recovered wood) energy potential is covered in the Addendum to the report. Potential output (based on volume to tip) at present is 1.1 million cubic metres, scheduled to increase to 1.8 million cubic metres by 2028.
Work in the Forest Energy research programmes has shown that if first thinnings are harvested as chipped whole trees, output can be increased by up to 50%. Not all stands are suitable for whole-tree harvesting, but nevertheless a very significant increase in harvested volume can be obtained using such a method. Similarly substantial amounts of wood for energy can be harvested on clearfells, where logging slash can be harvested for energy. Again this is not possible on all sites, because there is a need to retain a larger proportion of slash on poorer sites as a nutrient source, or due use as a brash mat on soils with a poor ground-bearing capacity.
There are other sources of woody biomass, particularly from short rotation coppice (mainly willow) with a harvesting rotation of 2-3 years, or potentially from short rotation forestry (ash, eucalyptus etc.) on a rotation of 5-15 years. Yields of 10-12 tonne dry matter/ha/yr can be expected on suitable soils.
Finally, trees in parks and alongside roads, when felled for safety or other reasons, can be a source of woody biomass fuel.