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Understanding the relationship among environmental factors, overstory and understory is a key step for the improvement of sustainable forest management. Our aim was to understand how environmental features (topographic factors) and overstory (tree species) composition affect understory (shrub and herb species) assemblage in sub-Mediterranean coppiced woods. The study area lies in the Monti Sibillini National Park (central Italy). In 205 plots (20 × 20 m) we collected topographic features and species cover values; moreover, we defined the Social Behaviour Type (SBT — i.e. species ecological and dynamic features) of each understory species. Data were analysed using Redundancy Analysis and Generalized Linear Modeling. We found that topographic factors shaped percentage cover of different tree species and hence determined forest community type. Topography-related factors were further mediated by the tree layer composition, in filtering understory assemblage, on the basis of species SBT. We found no effect of overstory species diversity on understory species diversity. However, the presence of tree species different from the dominant ones increased understory species richness. This effect was particularly notable in evergreen woods, dominated by Quercus ilex. We conclude that, to improve the management sustainability, coppicing management should be focused on the achievement of the greater tree species diversity.
This paper focuses on the issue related to the response of beech leaves to the opening of stand canopy resulting from a shelterwood cut of various intensity. Four research plots each with a different stand density provided different conditions for the development of foliage. The research was conducted on dominant, codominant and subdominant sample trees representing the mean stand diameter of all plots. The data were compared for the upper, middle and lower layer of tree crowns (each equals to one third of crown length). As for dominant and codominant trees, mean leaf area showed a tendency to increase towards the lower crown layer. As for subdominant trees, relation between the location of leaves in the crown and leaf area was similar to dominant and codominant trees but this trend was observed only on the plot most open. Only in the case of codominant trees the leaf area was decreasing with a decreasing stand density. Greater stand opening results in a proportionally smaller leaf area. Growing conditions for subdominant tree leaves were completely different when compared to conditions for upper tree classes. On the plots with harvest cutting we observed that a decreasing stand density resulted in a general increase of leaf size. The only exception to the rule was the control plot where the parameters recorded were higher and inconsistent with the above described trend.
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