The makers of piano frames employ red spruce for certain parts; but as material for musical instruments its most important use is as sounding boards. All the commercial spruces are so used. Wood for this purpose must be free from defects of all kinds, and of straight and even grain. The sounding board’s value lies in its ability to vibrate in unison with the strings of the instrument. Spruce has no superior for that place. Red spruce bears abundance of seeds, the best on the highest branches. The seeds are winged, and the wind scatters them. They germinate best on humus. In spruce forests, clumps of seedlings are often seen where logs have decayed and fallen to dust. Seedlings do not thrive on mineral soil, and for that reason red spruce makes a poor showing where fires have burned. It does not spread vigorously in old fields as white pine does. It must have forest conditions or it will do little good. For that reason it does not promise great things for the future. It grows very slowly, and land owners prefer white pine, where that species will grow. If spruce is to be planted, most persons prefer Norway spruce (_Picea excelsa_) of Europe. It grows faster than native spruces. It is the spruce usually seen in door yards and parks. BLACK SPRUCE (_Picea mariana_) grows much farther north than red spruce, but the two species mingle in a region of 100,000 square miles or more northward of Pennsylvania and in New England and southern and eastern Canada. Black spruce grows from Labrador to the valley of the Mackenzie river, almost to the arctic circle. It is found as far south as the Lake States where it constitutes the principal spruce of commerce. In some of the swamps of northern Minnesota and in the neighboring parts of Canada it is little more than a shrub, and trees three or four feet high bear cones. On better land in that region the tree is large enough for sawlogs. It passes under several names, among which are double spruce, blue spruce, white spruce, and water spruce. The common name black spruce probably refers to the general appearance of the crown. The small cones (the smallest of the spruces) adhere to the branches many years, and give a ragged, black appearance to the tree when seen from a distance. The wood is as white as other spruces. Trees vary greatly in size. The best are 100 feet high and two and a half feet in diameter; but the average size is about thirty feet high and twelve inches in diameter. That size is not attractive to lumbermen; but cutters of pulpwood find it valuable and convenient, and much of it is manufactured into paper. The wood weighs 28.57 pounds per cubic foot, and is moderately strong, and high in elasticity. It is pale yellow-white with thin sapwood. In Manitoba, lumber is sawed from black spruce, and it is cut also in the Lake States, but it is preferred for pulp.