Aspen Populus tremula. The Aspen is a Poplar that tolerates cold conditions. It is a smaller tree than most Poplars. It is a species that grows in cool regions across the whole of Europe and west Asia. (The American Aspen is a different species). It is more likely to be found in the north and west of Britain and is common in the Scottish Highlands. It is typically found in oak or birch woodland. It can spread by sending suckers up from its roots. Male and female flowers are on separate trees. Flowers are in the form of catkins.

Aspen tree

Aspen tree in early June. The Aspen is not as tall as other members of the Poplar family. It grows to a maximum height of 20m. Black Poplar can grow to 30m and Lombardy Poplar to nearly 40m.

Aspen leaf

The Aspen has a more rounded leaf than other members of the Poplar family. The stalk (petiole) of the leaf is flattened allowing the leaves to flutter in a slight breeze.

Aspen leaves in autumn

Leaves turn yellow in October/November.

aspen male catkins

Male catkins photographed at the end of February. The red anthers will soon open to release pollen grains onto the wind and fertilise the flowers of female catkins on a different tree.

Aspen female catkins

Fertilised female catkins in mid March. They stay on the tree until they release wooly seeds in April.

Aspen bark

The bark is smooth with diamond shaped pits.

Like all Poplars the Aspen has sharp buds. The terminal (end) bud seen here in winter is sharply pointed but has rounded bud scales

These are flower buds in December. Male and female flower buds look the same. Both produce catkins but male buds come out just before female buds.

Aspen tree in December