Dinamiche evolutive di post-selvicoltura nella foresta di Vallombrosa

Abstract

Abstract: The present study aims to highlight the successional patterns of forest stands showing a simplified structure and in which the silvicultural practices have been neglected along. Surveys were carried out in the Tuscan Apennine stands of Vallombrosa (3 pure silver fir stands, 1 pure chestnut old coppice, 1 pure douglas fir stand and 1 mixed silver fir-Norway spruce stand), where records on the stand dynamics of the last forty years are available (1966, 1987, 2004). The changes in structure are synthetically expressed by means of indexes (regeneration index, both structural and floristic diversity indexes). In three areas the growth pattern of silver fir regeneration was studied: the dendrochronological analysis showed different growth rates according to the different canopy cover degree. As for management aspects, according to the results of the present research, is emphasised that the canopy reduction is the prerequisite for a silviculture style aiming to enhance the system diversity. Gradual openings of the canopy, as the ones following selection or shelterwood systems, basing on long regeneration time span, are suitable to enhance the re-naturalisation both of silver fir stands (e.g., increasing the amount of broadleaves in the understory) and chestnut old coppices (e.g., favouring the coming of silver fir in the understory). Because the undisturbed conifer stands dynamics following the abandonment of forestry practice results very often uncertain as trend and direction, it appears important to follow up the process by mean of close-to-nature silviculture interventions. In this sense, the paper finally outlines the necessity to face the interactions between forest regeneration and wild ungulate populations, which currently represents one of the most dramatic problems of sustainable management.