Research note. Effects of fertilizer applications on growth and nutrition of pole sized Sitka spruce on oligotrophic peat

Abstract

During the early 1990s a marked decline in health of 20-30-year-old Sitka spruce in plantations on deep oligotrophic blanket peat across Northern Ireland was reported to research foresters by local managers. This site type represents a very significant proportion of plantations in this age class managed by the Forest Service of the Department of Agriculture for Northern Ireland, and was predominantly planted with pure Sitka spruce, in contrast to similar site types in Britain and the Republic of Ireland, on which lodgepole pine was the preferred species (Edwards, 1962; O'Carroll, 1962). Within affected stands the decline in health was often more pronounced in trees adjacent to roadside or internal drains. Trees in affected plantations presented symptoms of K deficiency in pole-sized Sitka spruce described by Binns et al. (1980) and illustrated by Taylor (1991); although this nutrient is applied to spruce plantations on organic soils in Britain as a standard procedure (Mclntosh, 1981; Dutch et al., 1990), early applications in Ireland are considered unnecessary except on flushed and fen peats