Paper Birch

2016 April 30

Here’s a tree that may well be easier to identify in the winter (when it has no leaves) than in the summer. It is Paper Birch, Betula papyrifera, which is one of Northern Michigan’s signature trees.

Paper.birch.full.height

These can be really beautiful trees, with their characteristic snowy-white bark that peels off in thin, papery layers[1].

Paper.birch.bark.closeup

The bark doesn’t start white, though. When the tree is young, or when the branches are only a few years old, they are a dark reddish-brown that looks like any of several other common trees. But after a few seasons, the dark bark peels away and it becomes white.

Paper.birch.young.branches

When they are growing in the open, birch trees tend to send up multiple trunks and grow in a clump, like this one. You’ll sometimes see single-trunk birch trees, but those tend to be in denser woods where there is more incentive to grow up towards the light instead of outwards.

Paper.birch.trunk.base

Anyway, these are fairly closely related to the alders that I posted last week, and have practically identical flowers – male catkins, and female cones. They also grow in similar environments to the alders, which is why we have both species in our back yard.

Paper birch has a very wide native range, but this range is mostly in Canada, only dipping down into the lower 48 US states in Michigan, Wisconsin, Minnesota, and most of New England. They like the climate on the cold and humid side. They tend to be one of the first trees to colonize open spaces on the way to converting it to woodlands, so a “young” forest is likely to have a lot of them. It is only so-so as a lumber tree, although its bark is relatively famous as a material for making canoes out of. The bark is not only water-resistant, but also rot-resistant, to the point where we regularly see fallen birch trees where the wood has rotted away but left the bark intact as an empty paper tube.

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[1] I almost wrote that it is “paper-like” bark, but thinking about it, maybe it isn’t just “like” paper. What is paper? It is a thin sheet of cellulose fibers, normally made from wood. What is birch-tree bark? A thin sheet of cellulose fibers, made from wood. I think it actually is paper! Maybe with a bit of lignin and resin mixed in to make it waterproof, but paper nevertheless.

One Response
  1. Carole permalink
    April 30, 2016

    River birch is more common here in northwest Florida. The bark of your paper birch reminds me of the invasive Melaleuca, the seeds of which were distributed over the Everglades by air to help dry the River of Grass up.

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