Betulaceae is the common name for the birch family, a family of nut-bearing trees that includes hazels, alders, and other types of trees. In total, more than 120 species in six genera are categorized as part of the betulaceae family. The wood of these trees is hard and sturdy and, though the wood has largely fallen out of favor in place of metal and other man-made materials, it is still occasionally used for chopping boards, tool handles, and similar items. Researchers believe all six genera originated in China. This group of trees is also believed to be around 700 million years old, with hard evidence of them existing 20 million years ago.
Birch trees are perhaps the most commonly known tree belonging to the betulaceae. This type of tree is hardy, spreads relatively quickly, and can become problematic if the spread of its seed is not controlled by grazing animals. In general, all species of birches are small to medium in size. The coloring of the tree bark differs depending on the species, ranging from yellow to black. While there is some difference in leaf shape between the species, it is subtle.
Alders also belong to the betulaceae family, growing in North America and most of Europe. It is similar in appearance to birches, but there are some key differences. For example, the female alder tree has woody catkins, which are petal-less flower clusters that can sometimes resemble small pine cones. Some species of alder are officially classified as weeds in New Zealand due to their quick growth and spreading ability.
Another member of betulaceae is the hazel genus, which has round leaves and flowers similar to birches and alders. This tree also has several natural hybrids, meaning that different hazel species can naturally reproduce with one another to create other, new species. Some botanists do not believe this tree belongs in the betulaceae family.
Yet another betulaceae member is the hornbeam genus, which has relatively small trees. These trees mostly occur in Asia, with just a couple species found in North America and Europe. Hornbeams have extremely hard wood that is sometimes referred to as ironwood. They are commonly used for flooring or turned into pegs for windmills. Hornbeam is far less popular now that metal, plastic, and other man-made materials are common. Unlike hornbeam wood, these man-made materials are easy to work with, and can be molded into different shapes.
