koivupuu

Koivupuu, commonly known as birch in English, refers to a genus of trees and shrubs in the family Betulaceae, native to temperate regions of the Northern Hemisphere. The name "koivupuu" is derived from Finnish, where *koivu* means birch and *puu* means tree. Birches are known for their distinctive peeling bark, which ranges in color from white to silver, brown, or black, depending on the species.

There are approximately 40–60 species of birch, with the most well-known being the European white birch (*Betula pendula*), the downy birch (*Betula pubescens*), and the paper birch (*Betula papyrifera*), which is native to North America. These trees typically grow in cool, moist climates and are often found in forests, along riverbanks, or in open meadows. Birches are deciduous, meaning they shed their leaves annually, and their leaves are simple, alternate, and serrated.

Birch wood is lightweight, soft, and easily worked, making it useful for various applications such as furniture, plywood, and traditional crafts. The bark has historical and cultural significance, particularly in Scandinavian and Indigenous North American traditions, where it was used for canoes, baskets, and as a source of resin for birch tar. Birch syrup, produced from the sap of certain species, is also a traditional food source.

Ecologically, birches play a role in forest ecosystems by providing habitat for wildlife and contributing to soil health through their leaf litter. Some species are short-lived compared to other trees, often regenerating through suckers from their roots. Due to their aesthetic appeal and ecological importance, birches are sometimes planted in parks and gardens for ornamental purposes. However, they are also susceptible to pests and diseases, such as birch borers and canker, which can affect their longevity.