Processes of loss, recruitment, and increment in stands of a primeval character in selected areas of the Pieniny National Park (southern Poland)

Abstract

Studies were carried out during 1987–1997 in four stands situated in the lower mountain zone, and representing the association <i>Carici-Fagetum abietetosum</i> (sample plots Facimiech and Walusiówka) and the community of a transitory character between <i>Dentario glandulosae-Fagetum</i> and <i>Carici-Fagetum</i> (sample plots Gródek and Przelecz Sosnów). The greatest volume increment was found in a pure fir (<i>Abies alba</i>) stand of Facimiech (9.4 m<sup>3</sup>/ha/year, i.e. 1.4% of actual stand volume determined in 1997) being in the optimum stage, phase of aging and regeneration, and the smallest one stand of Gródek (5.3 m<sup>3</sup>/ha/year, i.e. 0.9% of actual stand volume) being in the growing up stage, phase of selection forest. The stand of Przelcz Sosnów was characterized by the greatest mortality of trees (volume of loss, i.e. 13.5 m<sup>3</sup>/ha/year). In this stand of a transitory character between the growing up and optimum stages, due to rapid mortality of fir the break up of the stand took place, and in consequence the growing up stage, phase of a little diversified stratified structure was developed. Volume of recruitment was the greatest in the stand of Facimiech, i.e. 0.05 m<sup>3</sup>/ha/year. In three fir (<i>Abies alba</i>)-beech (<i>Fagus sylvatica<i>) stands the proportions of fir and beech in stand increment differed from their proportions in stand volume. The percentage of fir in volume increment was smaller, and that of beech greater, than their percentages in stand volume. Processes of increment and mortality of fir and beech pointed to a progressive process of changes taking place in stand species composition, expressed by the increase of beech and the decrease of fir. The knowledge about values of loss, recruitment, and increment, expressed by the number of trees and volume units, may be of help in determination of the amount of cut in productive and protective forests managed according to a close-to-nature silviculture.