Birch are deciduous trees that belong to the family Betulaceae. There are around 60 different species of birch that grow around the world. Birch require well-drained soil, enough moisture and direct sunlight for the proper growth. It usually grows near lakes and rivers. Birch is known as pioneer species because it easily populates habitats destroyed by fire. This plant is mainly cultivated because of its ornamental beauty and high-quality wood. Out of 60 birch species, 11 are listed as endangered mainly due to habitat destruction and various fungal diseases. Common birch in our area are yellow birch, river birch, white/paper birch, and the weeping birch.
Birch are medium-sized trees that can reach 30 to 50 feet in height. Some species may grow to the height of 80 feet under appropriate conditions. Birch have green leaves that are oval or elliptical in shape. Leaves are single or double serrated on the edges. Bark of the birch can be white, grey, yellow, silver or black in color. Young trees have smooth bark. Deep ridges on the bark are characteristic for the older plants. Bark of all birch species (except Grey Birch) peels off in long horizontal strips. Birch have shallow root systems which can damage sidewalks and roads in urban areas. Individual flowers are arranged in long clusters known as catkins. They hang from the branches during the summer. Birch trees produce fruit called “samara” which can release around 1 million seeds each year. Wood of birch tree is highly flammable. It can catch a fire even when it is wet. Because of that, birch tree is used as high-quality firewood. Birch tree can live from 30 to 200 years, depending on the species, quality of the soil and climate. Pollen of the birch tree is responsible for 15 to 20% cases of hay fever in northern hemisphere.
The most widespread pest on birches is the bronze birch borer. The birch leaf miner and the Japanese Beetle are also commonly found on birches. Other pests on birch trees include aphids, caterpillars, leafhoppers, sawflies and worms. Birch trees are susceptible to several fungal and bacterial diseases that cause leaf blisters, leaf spots and leaf rust.