Monitoring forest condition in Ireland (1988-1991).

Abstract

A range of 878-995 trees were assessed for vitality status over the years 1988-1991, in two projects equally funded by the EC and the Forest Service, Department of Energy. Four species were studied in a total of 47 plots distributed around the country: Sitka spruce (Picea sitchensis), Norway spruce (Picea abies), lodgepole pine (Pinus contorta), and noble fir (Abies nobilis). Forest damage levels, amongst the lowest in Europe, were very low in the spruces, and almost negligible in lodgepole pine and noble fir. Exposure and insects were the most common causes of damage, being influenced greatly by the position of the assessed tree (damage increasing as follows: internal> internal edge> external edge) and altitude, and less so by age, soil type, and nutrition. Forest condition in the spruces improved from 1988 to 1991, the improvement being attributed largely to relief in climatic stresses, leading especially to reductions in insect populations (green spruce aphid, Elatobium abietinum) and water deficits. There was no evidence of long-term damage and, as such, the existence in Ireland of forest decline, as defined by continental Europeans, is questioned.