TREES
In November or December make a study of Canadian evergreens, choosing spruce, balsam, and cedar if available. The pupils should learn to distinguish the different species by an examination of the leaves, buds, arrangement of branches, bark, seeds, and cones. The age of young trees can be determined by noting the successive whorls of branches. In this way also the age of the leaves may be determined. On some trees the leaves persist for seven or eight years. Evergreens are frequently used as Christmas trees and their branches for house decorations. On which species do the leaves persist longest? How do they compare with the pines? The leaves are always as old as the wood upon which they grow.
Have the pupils notice how the small leaves and horizontal branches resist the clinging of snow in winter. Each branch bends down enough to cause the snow to slide off on to the one next below, and so on, until it reaches the ground. The conical shape of the tree also facilitates this action of dislodging the snow. They will also notice that these trees are well adapted to withstand wind, as the top part, which is most exposed to the wind, is much smaller and more pliable than the part next the bottom. The gum, or resinous covering, of the buds protects them from injury by rain or snow. Some kinds of pine, such as the pitch pine, have a great abundance of gum and turpentine. Resin and pine tar are made chiefly from this species. Heat a piece of pine wood—a knot or root is best. The gum will be seen oozing out of the wood. Pine torches were much used in the early days of settlement in Canada. Examine the gum "blisters" in the bark of the balsam tree. From this source the "Canada Balsam" gum of commerce is taken. The gum and resin in the wood and bark help to preserve the wood from decay.