Jill Marie Schwendeman, age 11, of St. Paul, Minnesota, for her question:

How can evergreens stay green through the winter?

When the winter is at its worst, everything outdoors seems to shiver with cold. Surely you would expect the frost to freeze every green leaf solid. Plants, of course, have no internal heating systems to keep themselves warm as we do. Yet through the coldest winter, the pine needles and other evergreen foliage stays the same healthy green color. Obviously these trees have built in protection from the cold.

Actually, the evergreens have several ways to protect themselves through the winter cold. The pines and other cone bearing trees are stuffed with gummy resins. Aside from discouraging insects, these tangy tacky substances help to seal out the cold from the. fragile plant cells inside the trunks and twigs. Evergreens also manufacture heavy waxes on their leaf surfaces. These waxes are coats of insulation that shield the inner cells of pine needles from the frosty air. The shape of the skinny needles also helps by making it easy for piles of frosty snow to slide down off the boughs.