Grey alder (GAR)

Alnus incana

Native range

Native to Scandinavia and central Europe, has been planted in Britain for over two centuries, and has often been used on reclamation sites because of its nitrogen fixing capability.

Provenance choice

No provenance studies have been undertaken in Britain, so seed should be obtained from good British stands or possibly from western Sweden or Norway.

Site requirements

It is a light demanding pioneer species and cold hardy in Britain; however, it often spreads by root suckers which can be invasive. It is only moderately tolerant of exposure. It has a rather wider site tolerance than either common or red alder, being suited to moderately dry to wet soils of poor to medium nutrient regime. However, it does not tolerate alkaline soils and is not suited to peats or nutritionally very poor soils.

Pests and pathogens

It is more resistant to Phytophthora alni than A. glutinosa.

Use

Apart from its specialist role on reclaimed sites, this is likely to remain a minor species in British forestry.