Wild boar Sus scrofa L. winter selection among (1) different types of forest sites, (2) dominant tree species, and (3) age of stands was examined using the line transect method. The research was conducted over 125 km² of managed forest in the Myślibórz Forest District in northwestern Poland. The habitat preferences of wild boar were determined by the non−invasive method of counting tracks on line transects. Transects with a length of ~77,000 m were surveyed in January or February 2002, 2003, 2005, and 2006. Tracks of wild boar were recorded by GPS, with an automobile odometer and recorded for 6 types of forest sites, 4 classes of stand ages, and 3 dominant canopy species. The research included only those fragments of transects that had the same type of forest on both sides. Finally, wild boar tracks were counted on transects with a total length of ~24,000 m. During the winter, wild boar more often penetrated both young forest stands (up to 20 years old) and the oldest (60 years and older) stands, in association with resting sites and the availability of food in the upper layers of the soil. Middle−aged forest stands (20−60 years old), due to their structure, provide neither optimal protection nor maximum food resources, so they were the least penetrated by wild boar. In terms of canopy species, wild boar penetrated old stands dominated by oaks and beeches, where there are acorns and beech nuts in the upper layers of the litter. The greatest numbers of tracks were found in alder forests, perhaps because these provide trophic and protective conditions for wild boars during mild winters. The importance of different types of forest sites in the winter ecology of wild boar requires further research.

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