AbstractWhilst commercial forestry is unviable in the maritime climate of Orkney, SRC willow (Salix spp.) is a proven alternative woody biomass crop which can be grown as a local renewable fuel. A selection of 13 SRC clones were screened in Orkney and the most promising six clones which are recommended in Orkney are Ashton Stott, Tora, Sven, Tordis, Discover and Beagle. These clones produced an average biomass production of 6-8 ODT ha-1 a-1 in these Orkney trials. The greatest influence on SRC growth in Orkney appears to be the hyper-oceanic climate and the high levels of maritime exposure. Therefore modifications to best practice have been considered to optimise crop production in the local climate. In the Orkney the normal recommended practice of a first year cut-back lowers clone survival and does not
significantly increase biomass production and is therefore not recommended. SRC growth in Orkney is generally reduced, in comparison with other areas of the UK and therefore an increased density (20,000 plants ha-1) and short harvest cycles (2-3 years) are more probably suitable. SRC crops grown on ex-grasslands in Orkney do not require the application of additional fertilisers, in the first harvest cycle, due to the fertility of the soil. Moreover fertiliser applications increase weed competition of the crop and its susceptibility to damage by the wind. The disease willow rust (Melampsora spp.) is present but not currently at any level to cause concern.
However, as a disease prevention strategy SRC plantations in Orkney are
recommended to be grown as mixtures of at least six genotypes and rust should be continued to be monitored.
|Date of Award||30 Sep 2011|