Betula neoalaskana Betula neoalaskana Betula neoalaskana (syn. "B. resinifera") or Alaska birch, also known as Alaska paper birch or resin birch, is a species of birch native to Alaska and northern Canada. Its range covers most of interior Alaska, and extends from the southern Brooks Range to the Chugach Range in Alaska, including the Turnagain Arm and northern half of the Kenai Peninsula, eastward from Norton Sound through the Yukon, Northwest Territories, British Columbia, Alberta, Saskatchewan, Manitoba, southern Nunavut, and into northwestern Ontario. This tree typically grows to tall, occasionally up to , and achieves a trunk diameter of , and sometimes
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