Alnus cordata woodland

Broadleaved deciduous, non-riparian forests dominated by Alnus cordata, subendemic to Corsica (North-Eastern sectors of the island) and S-Italy (Campania, Basilicata and Calabria Regions). The dominant species is a relict from the Tertiary period and is also present in other areas, where it is considered not native. Biogeographically distributed on the Central-Mediterranean mountains, from the climatic point of view these forests develop preferentially between the hilly and the montane belts, occupying a transitional area between the deciduous oaks and the beech forests. From a geo-pedological point of view, they show a preference for siliceous substrata but can also be found on limestone. Alnus cordata tends to form forests, either pure or mixed with other deciduous species, such as Quercus cerris, Castanea sativa or, at higher altitudes, Fagus sylvatica. They tend to colonize steep slopes and sides of deep valleys. The Italian alder is a strong pioneer species with great affinity for mineral soils, and could largely expand after the drastic economic changes following the Second World War, when large agricultural areas were abandoned and left to natural evolution, especially at higher altitudes. These formations are characterized by very strong pace of growth in the juvenile stage, and quickly reach maturity (Bezzi et al. 1991). Unlike the other species of the genus Alnus, the Italian alder shuns soils where water stagnates for a long time, although it still shows a certain hygrophilous ecology. Regeneration occurs quickly and seedlings can grow fast after cutting or in clearings. Furthermore, Alnus cordata can play a prominent role in improving the soil, due to the presence of radical tubercles hosting microorganisms (Frankia alni) fixing the atmospheric nitrogen (Pirazzi 1984; Ducci & Tani, 2009).

These forest types often show a high environmental quality and host rare or endangered species.

Indicators of good quality:

● Dominance of Alnus cordata

● Presence of the distinctive woody associates and field layer

● Presence of the field layer flora typical of the region

● Uneven-aged canopy with signs of regeneration of woody dominants

● Presence of a well-developed structure of the tree layer

● Woodland permanent, not a successional stage; blocked dynamism due e.g. to the steep slope, where this forests represent the potential natural vegetation

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats