From barren to bushy
This is how the bare planting beds looked on the 6th of March in 2008, some six weeks prior to planting.
The trial, part of a wider project designed to investigate the potential for biomass production on the Western Isles, utilised a range of species and varieties including, Alder, Sycamore, Willow hybrids, and Poplars.
In autumn of 2012 the Trust started work on coppicing the plots (cutting the trees off some 100 to 150mm above ground level). Whilst the weather conditions over the winter of 2012 and spring of 2013 were milder than normal the resultant re growth from the coppiced stumps has been very encouraging, even from the smaller and less vigorous trees. Supported by the evidence from last year’s work the Trust will now proceed with the coppicing of fifty percent of each of the remaining plots. The un-coppiced half of each plot will be allowed to grow on for several more years to test whether delayed coppicing results in a more vigorous re-growth and a greater production of biomass.
So called “specimen” trees on each plot have been tagged and will be used as a source of future planting material, to re-plant the failed areas within the trial and for new planting elsewhere.
The photograph below, taken on the 8th of August 2013 shows the vigorous re-growth of trees coppiced 10 months previously. The real test will come later this autumn and winter when the soft re-growth will be subject to harsh salt-laden winds.
It will be a few years before we will have conclusive evidence of the potential for biomass production. However if the early indications are anything to go by, if appropriate species are chosen and established well, there would seem to be definite potential for biomass production under a suitable regime of coppice management. Whether or not the annual production of biomass dry-matter would be sufficient on its own to make it economic to fuel a biomass boiler remains to be seen, though the indications so far suggest that production would usefully supplement proprietary solid fuel in a suitable boiler.