Common Name: Italian Alder

General Information

Alnus cordata is a deciduous tree with a compact, dense pyramidal crown; it can grow up to 25 metres tall. The long, straight bole can be 70 - 80cm in diameter[, ].
The tree is harvested from the wild for local use as a source of wood. It is grown as a pioneer species to restore native woodland and makes an excellent shelterbelt tree. Where space is available, it is grown as an ornamental[].
This species has a limited natural range, but most of the range of this species occurs in protected areas. It also spreads readily and rapidly, and has become naturalised in much of Europe. It is therefore not considered to be threatened, however some threats have been identified, including; a reduction in clear cutting practices in protected areas which could have a negative impact on population growth, competition from other species, climate change at lower altitudes, and root rot caused by the pathogen Phytophthora alni. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

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Range

Europe - southern Italy, Corsica, Albania

Habitat

Open areas in hill and montane forests, often colonizing open Pine woods and bare soils after fires or landslides; at elevations from 300 - 1,500 metres[].

Properties

Conservation Status	Least Concern
Other Uses Rating
Habit	Deciduous Tree
Height	25.00 m
Growth Rate	Fast
Pollinators	Wind
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Alnus cordata is native to the warm temperate region of southern Italy, but also grows well in cooler regions of the temperate zone. It requires a mean annual rainfall of 1,000mm or more for it to thrive.
Prefers a sunny position in a moist, fertile soil. Thrives on poor and dryish soils, even on chalk, but prefers to be near water[, ]. Prefers a heavy soil and a damp situation[, ]. Grows well in heavy clay soils. Tolerates very infertile sites[, ].
A very ornamental tree[], it is very fast growing, reaching 12 metres tall in 20 years in an exposed maritime position at Rosewarne in N. Cornwall[]. Very tolerant of salt winds, it establishes rapidly in exposed positions[].
Trees can be coppiced with rotations of 15 - 20 years to provide biomass, pulp, fuel etc, or can be grown as high forest and cut when 70 - 80 years old for timber[].
This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

An excellent windbreak for maritime areas[], it grows quite quickly and establishes well even in very windy sites[]. Trees 5 years old from seed have reached 4 metres in height and are showing no signs of wind-shaping in a very exposed site in Cornwall[].
This is an excellent pioneer species for protecting the soil and re-establishing woodlands on disused farmland, difficult sites etc. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen - whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established[].
It has largely been utilised in central Italy for the reforestation of badly drained and wet soils, and for agro-forestry purposes. In recent decades,it has been widely used in Italy as a shelter species for walnut (Juglans regia), wild cherry (Prunus avium) and other noble hardwoods in intensive forest tree-farming programmes[].

Other Uses

The pseudo-cones are used as Christmas floral ornaments[].

The wood is a light tan to reddish brown, homogeneous, with a fine, even grain and with relatively wide annual rings. It can be used for construction purposes in wet conditions as the wood is virtually resistant to decay under water. It has been used for foundation poles for houses and bridges in Venice. The timber is also used for carving as well as for the production of moulding, furniture, panelling and plywood[, ].
The wood can also be used for firewood[].

Propagation

Seed - best sown in a cold frame as soon as it is ripe and only just covered[]. Spring sown seed should also germinate successfully so long as it is not covered[, ]. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring.
If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring[]. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them.
Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil.