Effects of Forestry Transformation on the Genetic Level of Biodiversity in Poland’s Forests

In this paper, the effects of Poland’s forest management evolution after 1945 on forest biodiversity at the genetic level were analysed. Forest biodiversity changes across the two politically and economically different eras (socialism, 1945–1989, and democracy, from 1990) are interpreted using three indirect indicators: forest regeneration and expansion, tree genetic resources, and threatened forest species. In the era of socialism, the total area of regeneration and reforestation gradually decreased, with these activities relying almost exclusively on cultivated reproductive material. After 1990, there was a relative stabilisation in the total area, with a noticeable increase in the use of natural processes to diversify the tree gene pool. Work on verifying and protecting the forest tree seed base, as well as on assessing the conservation status of an increasingly wide range of organisms, began in the era of socialism; however, it was intensified only in the era of democracy. In the latter case, the increase in the number of endangered species suggests a potentially negative trend. However, the actual assessment of the changes is not entirely clear due to subsequent changes in threat classification and increased knowledge of the occurrence of individual species. Dilemmas and problems related to the following issues require further discussion and resolution or implementation of further measures: the consequences of past choices regarding planted trees; the use of natural regeneration; the reduction in the forest tree gene pool as a result of artificial selection; incomplete knowledge about threats to the forest gene pool; the continued impact of threats and the possibilities for counteracting them; and securing funding for measures to protect biodiversity at the genetic level.