Aspens are particularly well-suited to floodplains. Their timber is of excellent quality, although at present it is not used commercially in Scotland because the supply is so limited. More than 160 invertebrates live in or feed on aspen trees, including 60 species of moths and butterflies. Beavers Beavers once occurred throughout Europe, but their highly-prized fur and the castor oil which they produce made them a target for hunters. It is thought that the last wild beaver was sighted in the north-east of Scotland in the 15th century.
Beavers live in small family groups in or near fresh water.
They eat only broadleaved trees and are particularly fond of aspen. European beavers do not dam as extensively as their Canadian cousins and so their reintroduction is less controversial. In Germany, where one of the few European beaver colonies have survived the medieval hunters, WWF has helped to conserve their habitats on the Elbe and Isar rivers, and in the 1970s was successful in reintroducing beavers to other sites.