Assessing, mapping and quantifying the distribution of foliar biomass in Great Britain

This study has quantitatively mapped the distributions and peak above-ground foliar biomass of the 1000 most prevalent plant and tree species in Great Britain (GB) on a 1×1 km2 grid. Each 1×1 km2 grid cell was assigned to one of 56 land classes on the basis of environmental and land cover attributes. The mean occurrence and cover area of specific plant species within each land class was derived from the results of the Countryside Survey 1990 [Barr CJ, Bunce RGH, Clarke RT, Fuller RM, Furse MT, Gillespie MK, et al. Countryside Survey 1990 Main Report. HMSO, 1993]. Species-specific biomass conversion factors, relating above-ground living plant biomass (excluding tree timber) to a unit of ground area, were used to convert cover areas into species biomass. British totals of species cover area and biomass were then calculated.Lolium perenne (perennial rye grass), Triticum aestivum (wheat) and Calluna vulgaris Ling (heather) covered the greatest areas of GB (26,811, 25,378 and 14,359 km2, respectively). During summer (prior to harvest), L. perenne contributed 20% of the peak standing biomass in Britain (25.6 Mt), followed by T. aestivum (18.8 Mt) and Hordeum vulgare (barley) (15.5 Mt). Picea sitchensis (Sitka spruce) was the dominant tree species in GB with the fourth highest peak foliar biomass (7.3 Mt). In total, 70 species accounted for 90% of the estimated summer biomass of GB. P. sitchensis and C. vulgaris dominated winter biomass. Predictive biomass distributions can be plotted for each species and examples of lowland and upland species are given. The predictions correspond well with known habitat preferences. Monthly variations in total biomass have also been plotted.