Aspen

Short Description

Aspen can grow up to 30 m tall. It is often multi-stemmed with a leaning stem. The crown is sparse and slightly irregular.

The leaves are rounded to heart-shaped and have a stalk. The upper side of the leaves is hairless and shiny. The leaf margin is rough and bluntly serrated.

The bark is yellow-brown and smooth with large diamond-shaped cork warts. In older trees, the bark is grey-brown with vertical fissures.

Individual florets are clustered in catkins. There are male and female trees (dioecious). The male flowers are more brown, the female ones more green in colour.

The fruits are small capsules with light seeds that can be windblown. They are clustered in drooping seed heads. The seeds are embedded in downy fluff.

In the city

In an urban environment, aspens are often found in wastelands or in sunny sites in parks. They tolerate drought stress and equally well prolonged wetness. They are salt and emission tolerant. Their potential to improve urban air quality by binding particulate matter is also discussed. This makes aspen a very suitable urban tree. However, as its light requirement is quite high, it is rather unsuitable as a street tree.