Saturday, October 15, 2011

Black Birch

The birches are understated in their yellow fall colors, amidst the generally brilliant reds and oranges of the maples. This year, however, I am taking more notice of the birches as the sugar maples have succumbed to fungal diseases from wet weather in spring and again in fall. All the birches that grow here -- yellow, black, gray, and paper -- turn a soft shade of yellow.

Black birch (Betula lenta) is more common in our woods than you might expect, especially here in southern New Hampshire and parts south. It seems to grow most abundantly on moist, protected northerly or easterly slopes, although it appears on dry, rocky sites too. I see it growing commonly among red oak and white pine. Last week Kodi and I hiked along a local trail, where the black birch saplings were lit up by the midday sun.


Up close the egg-shaped black birch leaves are distinct with sharply toothed edges and a heart-shaped base.


Crush the leaves or break a branch or chew on a twig and a wonderful wintergreen aroma wafts up. The oil of wintergreen is found in the inner bark -- once the only source of wintergreen oil, which is now made synthetically. The wintergreen aroma and taste is the reason it is known by another name: sweet birch.


The bark of the tree is distinct when the tree is young -- relatively smooth, dark gray, with horizontal lenticels. As the tree matures it takes on a much rougher look. Here is the trunk of a young black birch.


The cones bear tiny winged seeds that disperse by wind in the fall.


Black birch being at the northern edge of its range in these parts, seems to have adapted well to past changes and may do well as the climate changes. Black birch has filled in some of the "holes" in the forest that American chestnut once filled before it was decimated by the chestnut blight. Where gypsy moths have knocked back oaks and where hemlock woolly adelgid has killed hemlocks, black birch has moved in.

With its attractive fall colors, sweet wintergreen aroma, strong wood - it takes on a dark shade similar to mahogany, and adaptability, black birch is quite a tree.

2 comments:

  1. Makes me want to take a hike in the woods Ellen. I remember the tree ID weekends we used to go on in the Poconos in Northeastern PA. I was always surprised by the wintergreen aroma. I've never really looked for black birches here in Philadelphia but I'll be paying more attention now.

    A very nice portrait of a lovely tree. And I love your new photo at top of blog.

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  2. Hi Ken,

    I think black birch must be common down your way. Thanks for the note. I wanted to stay and visit with the little bear that we saw last week but decided that wasn't a good idea!

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