Betula nana Betula nana Betula nana, the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. It is a monoecious shrub growing up to 1–1.2 m high. The bark is non-peeling and shiny red-copper colored. The leaves are rounded, 6–20 mm diameter, with a bluntly toothed margin. The leaves are a darker green on their upper surface. Leaf growth occurs after snow melt and become red in autumn. The wind-pollinated fruiting catkins are erect, 5–15 mm long and 4–10 mm broad. "Betula nana" is native to arctic and cool temperate regions
Betula lenta male catkins pendulous, the female catkins erect. The fruit, maturing in fall, is composed of numerous tiny winged seeds packed between the catkin bracts. Seed production mainly occurs in trees that are between 40 and 200 years old, although light crops may occur as early as 15 years and as long as the tree lives. Contrary to common knowledge, the lifespan of "B. lenta" is typically around 200 years, and many individuals will reach 250 and even 300 years. The oldest known "B. lenta" has been confirmed to be 368 years old, and the species may live even longer than