Contrasting patterns of tree features, lichen, and plant diversity in managed and abandoned old-growth chestnut orchards of the northern Apennines (Italy)

In mountain regions of southern Europe, old-growth chestnut orchards maintained by traditional management were a key component of the economic, cultural, and ecological heritage. Currently, many stands are abandoned due to decreased economic sustainability even though, according to European policies, the loss of traditionally managed old-growth chestnut orchards should be contrasted to prevent biodiversity loss. In this study, we preliminarily mapped the remnants of old-growth chestnut orchards across a region of the northern Apennines (Italy) with a strong tradition of chestnut orchard cultivation. Then, we assessed the effects of management/abandonment in terms of tree features (e.g. size, crown structure, health conditions), occurrence and abundance of target epiphytic lichens, and richness and composition of understory vegetation. Our results revealed contrasting patterns of tree features, lichen, and plant diversity in managed and abandoned old-growth chestnut orchards of the northern Apennines, supporting the view that traditional management is fundamental for the long-term maintenance of healthy veteran trees, the enhancement of epiphytic lichens related to old-growth conditions, and plant diversity. This indicates that 1000 years of chestnut civilization represent a cultural heritage that benefits nature conservation, promoting a virtuous interplay between human activities and biodiversity. For this reason, policies aimed at sustaining traditional management in old-growth chestnut orchards are indispensable to avoid the degradation and loss of this habitat and its centuries-old cultural and ecological legacy.