Old-growth forests: report from the plots established by Aldo Pavari.

Abstract

The canonical attributes of old-growth forests, their importance for management approaches fostering the development of structurally complex conditions are reported. The relict presence of primary forests led to withdraw from the regular silvicultural management patches of forests and assign them to a non-intervention regime. They have been referred to as “unmanaged forest reserves”. In this context, at mid 1900, A. Pavari established a network of 24 permanent plots at the purpose of “saving from anthropogenic disturbance and studying the natural evolutive pattern of different forest types to establish wellgrounded rules of management”. Most of plots set up by Pavari have nowadays lost their effectiveness because of various occurrences. Five plots are described here as for their numerical, structural and compositional dynamics. The recorded parameters draw systems that, even if far from equilibrium, show the occurrence of positive evolutive patterns. Differences to natural forests are, basically, the heritage of the previous multiple uses of forest soil and stand as well. On this basis, the component species have modified their presence in term of richness, evenness and dominance, depending on their auto-ecology,resistance or resilience. The long-term monitoring of primary forests and secondary systems left to the natural evolution finds out manifold, sound reasons today. The practice of ordinary management has been reduced greatly and the foreseeable trend is to increase further over the next period. According to its progress, many forests are experiencing a prolongation of the prearranged rotations and a post-cultivation phase is becoming the rule; stands are therefore getting older. Findings by old-growth forests and unmanaged forest areas monitoring will provide references for managing this diffuse condition.