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The goal of this study is to assess the impact of different thinning approaches for coppice conversion into high forest of Turkey oak stands in Italy. The stand structure and the tree/shrub diversity were analyzed in 27 long-term monitoring plots from 7 experimental trials in the Colline Metallifere district (Tuscany, Central Italy) to verify the consistency of the original cultivation goals with the current stand structures. Three different approaches were applied from 1969 onwards: thinning from below, selective thinning, and no-management. Three indexes of specific diversity (Specific Richness, Shannon index and Importance Value) and two indexes of vertical diversity (Vertical Evenness and Coefficient of variation of tree height) were used to analyze and compare the outcome of management practices. The results showed a significantly higher dimensional variability and basal area, and a more complex vertical diversity in control plots and in the plots subject to selective thinning, as compared with plots subject to thinning from below. Tree species richness was high in all plots, independently of the thinning type applied. Based on our results, we suggest Turkey oak-dominated transitory stands to be initially managed by thinning from below, which is easy to be implemented and economically feasible. Selective thinning may be applied later with the aim of promoting sporadic but valuable tree species and increasing tree species diversity.

Tree-oriented silviculture is an innovative approach of forest management aimed at enhancing a limited number of early-selected crop trees whose growth is favored over the full rotation period by applying frequent thinning in their neighborhood. This approach was originally applied to high forests, but can also be applied to coppices to maintain or improve biodiversity by selecting valuable timber trees and/or minority species as target trees. The main limitation of this silvicultural option is the need of specialized and qualified operators in all the phases, from selection of crop trees to logging operations. In this study, experimental trials were established by the Forest Research Centre of Arezzo (Italy) to verify the suitability of this approach to different structural and enviromental conditions. In coppices characterized by fast growing species such as chestnut, tree-oriented silviculture has been applied to a limited number of crop trees (50-100 ha) to obtain more valuable and largersized assortments in a shorter rotation period, reducing at the same time the silvicultural costs. In mixed coppices, where the ordinary management (coppicing) was applied, the abandonment or the conversion into high forest gave rise to a progressive loss in terms of species composition. Contrastingly, thinning  focused around a few (5-20) trees of sporadic species allowed to maintain a high level of biodiversity,and led to favorable conditions for growth and regeneration of these species.