Our work focuses on the natural drying of woods in winter. It aimed to compare the natural drying process of three wood species: Scots pine as coniferous species, sessile oak as ring-porous species with a marked heartwood and silver birch as a sapwood species with a diffuse-porous structure. The research was carried out in central Poland. We collected logs from a 41-year-old stand destined for thinning. We stacked the logs randomly in one pile. The experiment took place between November 30, 2016 and April 4, 2017. All the samples were measured individually every two days throughout the experiment. We found logs lost weight during the experiment, especially pine (12% of total mass), less so oak and birch (7%). We recorded the biggest decrease during the last month (in spring). The wood moisture content decreased the most in pine and the least in oak heartwood. The stepwise regression model explains the impact of weather at 58%. Relative humidity was the most significant factor (0.58), followed by temperature and wind. We observed that weight loss and diameter are related to different degrees in the tested species, which probably depends on the sapwood area. Our observations show that natural wood drying in winter is a slow process that speeds up in the spring.

Keywords: natural drying, woodpiles, wood storage, moisture content