Carbon storage and sequestration in the forests of Northern Ireland

Abstract

The rate of accumulation of carbon in forests and woodlands in Northern Ireland was estimated using the record of forest planting since 1900 and a model that calculated the flow of carbon from the atmosphere to trees, litter, soil, wood products and back to the atmosphere. It was assumed that all conifer forests had the carbon accumulation characteristics of Picea sitchensis, and upper and lower estimates of carbon storage were calculated assuming Yield Class 16 m3 ha-1 a-1 unthinned and Yield Class 14 m3 ha-1 a-1 thinned. Broadleaved woodlands were assumed to have the carbon accumulation characteristics of Fagus sylvatica, Yield Class 6 m3 ha-1 a-1. Northern Ireland currently has about 78 300 ha of forest, 83 per cent of which is coniferous, 77 per cent state-owned, mostly planted since 1945, with peak planting in 1960-1975. In 1990, conifer forests contained 3-4 MtC (trees + litter) and broadleaved woodlands contained about 0.8 MtC (trees + litter + new forest soil). In 1990, conifer forests were sequestering 0.15-0.20 MtC a-1 and broadleaved woodlands about 0.025 MtC a-1. To maintain these sink sizes, new conifer forests need to be planted at 1500-2000 ha a-1, and new broadleaved woodland at 100-150 ha a-1 in addition to full restocking. Current carbon sequestration by Northern Ireland forests represents around 6.5-8.2 per cent of the total for UK forests and is greater per hectare than in Britain because the average forest age is younger in Northern Ireland.