The white willow is the commonest tree-size willow in Europe, attaining heights of 20 to 25 metres with trunks one metre across and living from 80 to 120 years. Old trees have thick, vertically furrowed, yellow-brown bark. The yellowish flowers, arranged in catkins, appear in April, while those borne on the female trees ripen into capsules with small, down-covered seeds in early June.

The goat willow is a shrub or small tree 3 to 10 metres high with a broad, broom-shaped crown. It reaches an age of 40 to 60 years or more. The bark is smooth and grey, with rhomboid lenticels. The twigs are stout, the buds ovoid, and the branches with their large catkins, that appear before the leaves, are popular heralds of spring, being among the first wild flowers to be sold at flower stalls. During the flowering period in March the goat willow is a very attractive ornamental, male individuals resembling a large yellow bouquet at this time.

The black walnut was introduced into Europe in 1629. It is cultivated there as a forest tree for its high quality wood. It is more resistant to frost than the common walnut, but thrives best in the warmer regions of Europe on fertile, lowland soils with a high water table. It is a light-demanding species. The wood is used to make furniture and rifle stocks, and oil is pressed from the seeds.

The centre of the walnut’s natural range is in central Asia, from where it extended as far as the Balkan Peninsula. It was cultivated by the Greeks and Romans, the boundary of its distribution shifting markedly northward. Today it is widely planted in North Eastern and central Europe, the U.S.A. and other countries. It is a tree which in central Europe does best on sheltered slopes in warm, hill country. On limestone rock it grows up to elevations of 700 to 800 metres.

Often growing alongside brooks near villages are the so-called pollarded willows, the result of cutting-back the trunk and of repeated cutting of the branches over a period of 2 to 5 years. In practice, new individuals are propagated by cuttings.

The butternut is resistant to frost and requires less fertile and moist soils than the black walnut. However, as it grows more slowly and the wood is not of high quality, it is cultivated in Europe mainly as an ornamental specimen tree in parks and gardens.