In this study, large differences in the rate of drying was found between species. The drying rate is significantly larger for Norway spruce wood than for the deciduous species. This is probably due to the higher moisture content at the time of felling and faster diffusion of water through the more porous coniferous wood. Norway spruce may be felled as late as the beginning of June and still reach a moisture content of less than 180 g kg 1 total weight for the heating season (OctobereMay) the same year. The firewood should however be placed under shelter no later than October as it will otherwise regain some of the moisture during the fall and winter. Most of the drying occurs during the summer (June and July) and very little occurs during the fall and winter (see also Ref. [16]). When firewood is felled in August or later it will not reach a suitable moisture content before the heating season.