The rate of accumulation of carbon in forests and woodlands in Norther
n 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 characte
ristics of Picea sitchensis, and upper and lower estimates of carbon s
torage were calculated assuming Yield Class 16 m(3) ha(-1) a(-1) unthi
nned and Yield Class 14 m(3) ha(-1) a(-1) thinned. Broadleaved woodlan
ds were assumed to have the carbon accumulation characteristics of Fag
us sylvatica, Yield Class 6 m(3) ha(-1) a(-1). Northern Ireland curren
tly 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 plantin
g in 1960-1975. In 1990, conifer forests contained 3-4 MtC (trees + li
tter) and broadleaved woodlands contained about 0.8 MtC (trees + litte
r + 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 mai
ntain 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 ad
dition to full restocking. Current carbon sequestration by Northern Ir
eland forests represents around 6.5-8.2 per cent of the total for UK f
orests and is greater per hectare than in Britain because the average
forest age is younger in Northern Ireland.