La gestione dei rimboschimenti di pino nero appenninici. I diradamenti nella strategia di rinaturalizzazione

Management of black pine stands in the Appennines. Thinning for renaturalisation - The first stages of management and renaturalisation of black pine plantations are founded on thinnings, which are primarily aimed at increasing physical stability and creating favourable ecological conditions for the natural regeneration of autochthones species. The research aims at experimenting two different intensities in the first thinning of a black pine young stand of good fertility in the area of Pratomagno (Arezzo). The effects of the thinning on the main dendrometric parameters have been evaluated by means of three different inventories: i) 1998 before and after thinning, ii) 2002, iii) 2006. In particular the dynamics of horizontal structure (permanent transects) and the trend of stability indicators (height – diameter ratio, crown depth, crown area, crown diameter – stem diameter ratio) have been investigated. Thinning intensity is strictly related to increasing of the pine forest functionality. In a thirty years old stand in good fertility conditions a “strong thinning” (reduction of about half the number of trees and 35% of basal area) is proved to be effective in increasing stability and stimulating crown growth.