Folk traditions concerning the "right" time for felling of timber are present in the countryside and among the elderly connoisseurs of wood. The time of felling is supposed to influence important properties of wood. The objective of this research was to check whether these traditions can be professionally justified or not. We collected oral information on tradition of tree felling and wood-working, to evaluate the traditional rules in sense of modern science. Traditions concerning the tree felling were collected by an inquiry in 3 different regions of Slovenia: Selška dolina, Tolminsko, and Kozjansko. It was shown that there exist regional differences in traditional rules. According to tradition, in all the regions felling "na suš" was practiced after felling the entire tree with crown was left in the forest for up to 3 weeks, and the leaves contributed to drying of the stem wood. In Selška dolina such a practice was used for conifers felled in spring, and for beech wood felled from 15th August to 8th September. Such a procedure is not known in Tolminsko, where conifers and deciduous trees are being felled mostly in winter time. In Kozjansko the rule of felling beech wood "na suš" from 15th August to 8th September is considered. The use of lunar calendar and the lunar rules seems to be the same in all 3 regions; felling of timber was done in the period from full to new moon. Today's professional knowledge cannot confirm that following the traditional rules defining the time of felling improves relevant properties of the wood.