Natural loss of trees, recruitment and increment in stands of primeval character in selected areas of the Bieszczady Mountains National Park (South-Eastern Poland)

Abstract

In three investigated stands the highest increment (8.8 m3/ha per year, i.e. 1.5% of the actual stand volume, measured at the end of the control period) was reached by Jawornik I stand in the initial period of the growing up stage, and Tworylczyk stand in the advanced growing up stage (7.4 m3/ha per year, i.e. 1.2% of the actual stand volume). Jawornik II stand, in the optimum stage, the aging phase, had the lowest increment (3.9 m3/ha per year, i.e. 0.7% of the actual stand volume). The process of a natural volume loss was the most intensive in Tworylczyk stand (7.6 m3/ha per year), a little less intensive in Jawornik II stand (7.1 m3/ha per year), and the least intensive in Jawornik I stand (5.8 m3/ ha per year). The analysis of tree loss, recruitment, and increment, and the relations between these processes, can form the basis for a conclusion that stable stands developed in the Carpathian primeval beech forests in the years 1988–1998. Such steady processes can be used for the development of a stable, multifunctional model of the forest managed by the selection system, or the Swiss irregular shelterwood system in the Carpathian beech stands of a similar structure.