Assessing and promoting old-growthness of forest stands: Lessons from research in Italy

Due to a long-standing history of human impact, it is rare to find in Europe old-growth stands associated to primary forests; the term "old-growthness" is more appropriate to assess old-growth forests in European countries: i.e. the degree to which forest stands, which may or may not have been impacted by humans, express the structural variability commonly found in old-growth forests. The paper focuses on operational methods to assess and promote old-growthness in countries, like Italy, where old-growthness detection is a difficult task because of the scarcity of "relatively old" forest stands. Lessons learnt from research experiences carried out in Italy are reviewed; research findings mostly come from unmanaged tracts of previously managed forest stands that have reached structural and compositional traits typical of the mature stage of forest dynamics. A commentary discussion is provided on the following topics: (i) how to operationally assess old-growthness of forest stands, by coupling remote sensing based approaches and snapshot inventories of structural features; (ii) what forest structural attributes appear to be more strictly related to old-growthness in Mediterranean forests and (iii) how to promote old-growthness in managed forest stands. The paper concludes pointing out open research questions and pragmatic considerations for managing forests for old-growthness.