Modelling and mapping the potential productivity of Sitka spruce from site factors in Ireland.
Keywords: Sitka spruce, productivity models, land-use, spatial modelling, site classification.
AbstractThe main objective of this study was to quantify the potential productivity of Sitka spruce (Picea sitchensis (Bong.) Carr.) in Ireland. Productivity data from 201 Sitka spruce stands were used to relate general yield class (GYC) to low resolution digitised data (climate maps, soil and subsoil maps), and easily assessable site quality variables (site and vegetation classifications). Three models were derived that explained 45-52% of the variation in GYC. A spatial model was used to derive spatial predictions of productivity and map the potential productivity of Sitka spruce throughout Ireland in a Geographical Information System (GIS). This model predicted that 73% or 5.103 million ha of the total land area in Ireland was capable of producing Sitka spruce growth of yield class 14 or greater. Furthermore, 62% of the total land area could potentially result in GYC 20 or higher yields. The results of the analysis indicated that significant potential exists for forestry development on marginal agricultural land where forestry expansion may not necessarily be in conflict with the achievement of growth targets from other agricultural subsectors (e.g. dairy and beef). A practical model was also developed, which may serve as a guide to evaluating the potential productivity of suitable sites for afforestation. Typically the confidence limits for fields with wet or dry grassland were ± 2.0 to 2.8 m3ha-1yr-1 and blanket bog was ± 2.4 to 2.9 m3ha-1yr-1. A forecasting model, developed to derive predictions of productivity on forested land, might also be used to forecast timber yields.
How to Cite
Farrelly, N., Ní Dhubháin, Áine, & Nieuwenhuis, M. (2011). Modelling and mapping the potential productivity of Sitka spruce from site factors in Ireland. Irish Forestry. Retrieved from https://journal.societyofirishforesters.ie/index.php/forestry/article/view/10055