Nature Notes

Vol. X December, 1932 No. 12

Do You Know Your Trees in Winter? Cottonwood, Willow, Sycamore branches

The coming of fall, the falling of the leaves from the deciduous woody plants and their preparation for the long winter months does not necessarily signify the end of botanical interest for the season.

Yet, with the first chill of winter and the denudation of our deciduous trees and shrubs many familiar arboreal friends lose their identity. But why? Examine them. They still posses many characters by which they may be recognized and those are as decisive as those with which we are familiar in the summer. The buds, leaf, stipule and vascular bundle scars; character of the twig itself; the bark; the form of the tree - these and many others serve to make positive identification far from difficult. We need but to examine them with such characters in mind. Mt. Rainier National Park does not possess a great number of deciduous tree species. To be exact there are but five genera of such trees native to this region - Cottonwood, Willow, Maple, Alder and Dogwood - though our woody deciduous shrubs are more numerous. And so, with those as a nucleus, the next few issues of Nature Notes will attempt to describe a few of the more common trees and shrubs - many of them native to this park - in the hope that you will better understand the opportunity for study that lies in winter botany.

(See also "Trees of N.Y. State" by Brown; "Winter Botany" - Trelease and "New England Trees in Winter" - Blakeslee and Jarvis)

Walnut branch

Beech branch

Alder and Catalpa branches

One would scarcely fail to recognize the Cottonwood, once its winter characters were firmly fixed in mind. The leaf scars are prominent and these, likewise, possess prominent vascular bundle scars while the buds themselves are possessed of several scales overlapping each other - having a decided "gummy" character. These characters differ considerably from those of another group of trees in the same family - the willows. Here one finds the bud possessed of but one scale instead of several - a most important character - while the leaf scar is narrow. Only one other common tree has buds protected by one scale. That is the Sycamore, familiar in many parts of the country either native or naturalized. But the winter characters of the Sycamore differ considerably from those of the Willow particularly in the case of the stipule scars which, in the latter case, encircle the twig. The walnut group would be readily recognized even without its most conspicuous character - the chambered pith. The stout twigs, large shield-shaped leaf scars and other characters proclaim it for what it is but it is the pith that is the most interesting. With your pocket knife split a walnut twig lengthwise. The pith, instead of being solid, is composed of numerous sections or chambers.

The long, slender, light brown buds which are oblique over the leaf scars and the slender, zig-zag twigs identify the beech. It is in the alder though that we find another striking character. As the willow has one bud scale; as the Sycamore has a stipule scar encircling the twig; as the walnut has chambered pith -- so the alder has buds that are stalked and the scales, instead of over lapping, are valvate - that is meeting at the edges.

Now all the tree groups mentioned had leaves that are arranged alternate on the twig consequently the leaf scars were alternate. Many trees and shrubs have leaf scars that are not alternate being opposite (as in the Dogwood and Maple) or whorled as in the case of the catalpa. This tree has large leaf scars in whorls of three along the twigs. The scars vary in size - one being larger or smaller than the other two in the whorl - and are possessed of numerous vascular bundle scars.

So study your trees and shrubs this winter. And when you come to the park for a winter outing take a few moments to examine this region botanically also. In either case you will find your time well spent and your knowledge of natural history enriched by a bit of understanding in winter botany.


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