A willow tree is a tree in the genus Salix, which contains around 400 distinct species of trees and shrubs native to the Northern hemisphere. While the weeping willow is one of the most common species, there are many other varieties, all sharing several things in common. They have a number of commercial uses, and the trees are also frequently planted as ornamentals, since some species have quite attractive growth habits.
Willow trees are scientifically classified in the genus Salix, of the larger family Salicacae, which also encompasses poplar and aspen. They typically have narrow leaves, while their cousins, the poplar, have rounded leaves. There are approximately 400 distinct species of these trees worldwide. Among the approximately 75 species found in North America. All are woody, meaning they occur as trees or shrubs.
A willow which has evolved in cooler regions of the world tends to take the form of a creeping shrub, rather than a tree, reflecting a desire to protect itself from severe weather and cold. Willows which develop in warmer regions will be much larger, often with very delicate branches which easily snap off, allowing the tree to propagate itself.
The trees prefer cool, moist soil. They are commonly found near streams, rivers, ponds, wetlands and floodplains. They occur in a wide range of climate zones, but are most common in the temperate zones of the Northern Hemisphere up to the arctic regions. They can occur farther north than any other angiosperm tree.
Willow wood can be used in a wide variety of projects, and the bark has historically been used to make medicines, as it contains salicylic acid, the original aspirin. Because they grow quickly and establish extensive root systems, they have also historically been used to control erosion. The trees are also quite popular among butterflies, leading some people to plantm the trees to attract butterflies to their yards and gardens. 1,4-Dimethoxybenzene, also called as hydroquinone dimethyl ether having the molecular formula C8H10O2, occurs naturally in willow and it appears to attract bees as it has a powerful response in their antenna.
Willow wood is too soft for lumber usage, but the pulp is occasionally used for paper. The branches are frequently used for baskets and wickerwork. Historically, the bark of trees have also been used for medicinal purposes as a predecessor to aspirin. Today, many willow varieties are used for ornamental landscaping. Additionally, they are sometimes purposely planted along riverbanks for erosion control.