Identifying Quaking Aspen and Paper Birch
For the casual observer it can often be difficult to distinguish quaking aspen from paper birch. That topic came up in a conversation recently. A friend mentioned that he cannot comfortably differentiate the two species. Both species are medium sized trees with light bark, but once a person learns what to look for, differentiating the two can become quite easy.
Winter can be a good time to learn the differences between paper birch and quaking aspen because the foliage does not obscure differences in the tree’s form, bark, branches, and canopy. Perhaps the most obvious characteristic to help differentiate quaking aspen from paper birch is to observe whether the tree has multiple stems or is a single stem. Most paper birch produces multiple stems from the base. There are often three or four stems growing outward from the base of a paper birch. Quaking aspen are overwhelmingly single stemmed.
Differences in the bark are also helpful in differentiating the two species. Paper birch has a paper-white bark that characteristically peels outward in places. The bark on quaking aspen, however, does not peel like paper birch, and the bark is a generally a bit darker and may have a greenish tinge. There may be some photosynthesis going on in there. That is not the case with paper birch.
The shapes of the canopy of quaking aspen and paper birch are also different. Quaking aspen typically has a long, slender, and straight trunk, with branches spreading and forming a rather rounded crown. Paper birch on the other hand usually has a more pyramidal shape, and as the tree ages, the crown becomes more irregular. Plus, paper birch is more finely branched than aspen, particularly toward the tips. The abundance of those finely divided twigs at the ends of the branches often gives the canopy margin a distinctly noticeable and crowded look compared to that of quaking aspen. They may also retain the flower clusters or catkins well into the winter.
So, make a point to check out some quaking aspen and paper birch this winter if you can. With a few closer looks the differences between the two will likely become more apparent. And for those of you that can already identify them, you can still enjoy the interesting colors and forms of these two trees in the cold winter landscape.