Spend Sunday afternoon with Steve Sader, Professor of  Forest Resources at University of Maine,  learning how to identify deciduous trees and shrubs in winter. Hand lenses and magnifying glasses helpful.

Deciduous leaves are scarce in winter, except on beech and sometimes oaks, and bark of young trees can be misleading. Not so buds and leaf scars.  Bud shapes, the number of bud scales, bud arrangement, leaf scares and twigs are features used to key out native and no-native trees and shrubs. Hirundo’s varied forests (wetland, mixed, upland) offers ample opportunity for practice.

Buds are the adaptation strategy of tree and shrubs to maximize food production and flower & seed development during the short active growing period in our northern climate. Buds, pre-formed the previous summer, hold miniature leaves or flowers, or both, depending on species. The trees and shrubs share the same quandary as Maine’s tourist industry. Spring is late, summer short and just like the tourist industry the woody plant has to replenish its depleted resources from the past winter, flower (prosper), produce seed (increase in size) AND make new buds for the next season (put up money) in just a few month!

Lucky for us, buds come in different shapes and sizes, with or without coverings (the bud scale) and are arranged opposite or alternate along the twigs. Some buds are shamelessly naked, as in the Wayfaring Tree (a non-native) and set on gray hairy twigs, with triangular leaf scar beneath. The willow wards off temperature fluctuation with one bud scale, the Red Osier dogwood with two, and the familiar silver maple, among other trees, uses several.

If two species occupy similar habitat, are alike in twig colour and have the same bud arrangement, as it is true for the Red maple and Red osier dogwood, the number of bud scales might just be the right aid for
further identification.

How do buds know when to burst open, to expose leaves to sunlight and flowers to pollination?

Ask Steve on February 19th, 2012 at 1pm.

See you then!