Urban Jungle

February 9, 2010

An American elm twig’s heralding of spring

Between snowstorms, warmer winter days are swelling the flower buds of the American elm, one of the first trees to bloom. Inconspicuous green and purple flowers should begin to emerge by March, long before the leaves unfurl.

A close look at this twig reveals more than three years of growth, with buds present only on last year's growth.

On this tree, new branch growth tends to emerge primarily from terminal buds, but some minor branching occurs from lateral buds.

As terminal buds open, their protective scales drop off, leaving behind distinctive terminal bud scale scars that circle the twig and remain visible for years, acting as a tick mark for each year's growth.

Late last summer, buds appeared on new extensions of the twig, just above the spots where leaves were attached. In the fall, each leaf left behind a scar -- and a tightly packaged promise for the spring.