by Kevin Strauss
While hiking on the Bass Lake Trail in the Superior National Forest last weekend, I noticed three-pronged yellow "seeds" on the sparkling winter snow. These fruits come from female paper birch trees (Betula papyrifera). The name literally means "shining paper-bearer." The Lakota name for this tree is literally "white bark tree."
Paper birch, also called "canoe birch" is one of the easiest trees to identify in the northwoods because of its papery-white peely bark. I first learned about paper birch tree as a teenager at Boy Scout camp in northern Minnesota. It was there that I learned that paper birch bark is highly flammable and a great fire starter. I also learned to only collect birch bark from dead and down trees, since peeling bark from live birches can kill the this thin-skinned tree.
These trees grow to about sixty feet in height and have branches that spread thirty feet in diameter. The average birch trunk is about 16 inches in diameter. Birches are fast-growing, relatively short-lived trees.
Usually one generation of birch trees will grown in an area before more shade-tolerant trees like Balsam fir and white spruce take over. You can see this happening across logged areas on Minnesota's north shore of Lake Superior and in logged areas of the Iron Range. Paper birch live 80-100 years, but may only last 40 years in more stressful environments like in the average household lawn. One reason that paper birch forests don’t last more than one generation is that paper birch is shade intolerant, meaning that it needs to grow in full or partial sunlight to grow. It can grow in dry to moist soil conditions, but it doesn't do well in hot or drought conditions. Paper birch is found across the northern half of North America and at higher elevations in the Appalachian and Rocky mountains, and is one of the dominant deciduous trees of the boreal forest.
Paper birch are termed a "pioneer" species, often germinating on burned over or cut-over land. Paper birch also stump sprouts from old stumps and often has more than one trunk emerging from one set of roots. Ecologists term them “nurse trees” that provide a protective canopy for the germination and growth of other species like red maple, white pine, balsam fir and white spruce.
Paper birches flower in early May and produces triangular yellow seeds in catkin-like fruiting bodies to be dispersed by the wind in fall and winter. These seeds germinate best in exposed mineral soil, free of leaf litter. By releasing their seeds in winter, paper birch can guarantee that their seeds will get plenty of moisture in the spring when they germinate.
So while winter seems like a time when plants and animals are just “waiting things out,” it is clear that some plants are already preparing for growth in the spring.
The Ely Timberjay