Fourteen birch stands at the age of 55-60 years, in the Dretyń, Miastko and Niedźwiady forest divisions, were investigated as well as diversity of environmental conditions of their occurrence with reference to the requirement of conversion into beech, beech-oak or oak forests. It was stated that variation of natural conditions of the analysed birch stands includes three forest site types (deciduous mesic forest, deciduous mixed mesic forest and coniferous mixed mesic forest), five soil types and subtypes (podzolic soils, rusty soils, brown rusty soils, brown lessive soils, pseudogley lessive soils), five different surface geological formations (outwash sands, fluvioglacial sands of crack formations, moraine sands, moraine clays, tertiary clays), four site moisture content levels (sites with a very poor inflow of ground water, sites with a very poor inflow of precipitation water, sites with a small inflow of ground water, sites with a small inflow of precipitation water), six current vegetation communities (birch communities with no distinct phytosociological classification, communities from the group of acidophilous communities representing Trifolio Geranietea sanguinei and Rubetum idaei class, a community related to Calamagrostio arundaceaea-Quercetum petraeae, community related to Fago-Quercetum petraeae, a community related to Galio odorati-Fagetum) and four communities of potential vegetation (Galio odorati-Fagetum, Fago-Quercetum, Calamagrostio arundinaceae- -Quercetum petraeae, Potentillo albae-Quercetum).

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