In late May the pairs of winged keys hang on short stems. Each key is about two inches long, fuzzy green, until ripe, twice the length of the smooth keys of the red maple, which are ripening at the same time.
It is good fun to lie under a maple tree, and watch the seeds as they fall. If the wind is strong, they shower down like rain. Each key separates from its mate, and as it lets go its hold on the twig, the wind catches its thin wing, and sends it whirling round and round. The heavy seed makes for the earth, while the flat blade above it acts as a parachute, or a sail, to keep it in the air.
How far does a silver maple send its seeds in these summer days, when they are falling? It is easy to answer this question by pacing the distance from the tree trunk in a straight line to the point where the farthest key falls. Go in the direction towards which the wind is blow ing, in determining this distance. It will be in teresting to run out another line from the tree trunk to find out how far the seeds are thrown on the side that is against the wind.
From the silver maple go to a red maple, and watch the harvest of these small-winged keys. Do a little measuring here, and find out if their smaller size and weight enables these seeds to sail further in the same breeze than those of the silver maple.
The sugar maple is known also as the rock or hard maple, because its wood is harder, and therefore slower to grow, than the two quick growing soft maples just described. This is the one whose trunk is tapped in spring, and the sap boiled down in great kettles over an open fire in the woods. When the water is all evaporated, solid cakes of maple sugar remain. If you are walking in the woods in winter, and come upon any trees bored with small auger holes, several near the base of each trunk, you may suspect that this is a grove of hard maples which the New England farmer calls his " sugar bush." Look at the twigs, and you will see that the plump round buds are set opposite, and the twigs are opposite on the branch. This is the way with all maple trees. Are the branches many, and do they shoot upward rather than outward, and form an oval head? This is the typical habit of young hard maple trees. As they grow older
the heavy lower limbs become horizontal. They are clean, hardy, vigorous trees, long-lived, de pendable, able to meet the storms, and to suffer the theft of their rich sap every spring without apparent loss of strength and vitality.
The leaves come out later than those of the soft maples. They are firm, and broad, with five pointed lobes between wide fissures that reach half-way to the stem. Margins of these lobes are wavy, never saw-toothed, like those of the silver maple. They are dark green above, with paler linings. In autumn they turn to yellow, orange, and red.
The flowers open in May, shortly after the leaves appear. They are in thick, hairy, yellow ish clusters. Some are pistillate, some staminate, in the same cluster. Those with the forked pistils remain and grow into smooth fruits to wards the end of summer. The keys of sugar maples are short-winged, like those of the red maple, but have stouter, thicker seeds. They are shed in late autumn and early winter.
Hard maples are among the best of shade trees, and the glory of their autumn colouring makes them one of the most to be desired among trees planted merely for ornament. A street planted to hard maples is well planted always. But people are impatient for trees to grow up. The slow growth of the sugar maple is discourag ing. It is a good plan to plant the quick-growing soft maples, and alternate with them the slow growing species. For a few years the soft maples are pretty, and with each year's growth they give more abundant shade. By the time the wind has crippled their long arms, and made the trees unsightly, the hard maples are coming on to take their places, and they need the room which is given them by the removal of their neighbours on to the left and right.
When I went into the woods of Oregon, I found the vine maple trees, which seems not to have sufficient backbone to stand upright. These trees start to grow erect, but their weight soon over comes their strength, and they droop, but keep on growing, with their limbs prostrate on the ground. The wet land in many places was cov ered with a network of the interfering branches of these serpentine maple trees.