 found 32 tonnes more carbon per hectare (13 tonnes per acre) under a 14 year old miscanthus field than in the control site, suggesting a combined (C3 plus C4) mean carbon accumulation rate of , or 38% of total harvested carbon per year.Likewise, Milner et al.suggest a mean carbon accumulation rate for the whole of the UK of 2.28 tonnes per hectare per year (also 38% of total harvested carbon per year), given that some unprofitable land (0.4% of total) is excluded.