At its best this tree may exceed a height of 100 feet and a diameter of three; but the average for mature timber in the best part of its range is sixty or eighty feet in height, and two in diameter. The flowers appear with the leaves in early spring, but the seeds do not ripen until autumn, when they are bright red. They are winged, and usually two grow together, but they sometimes become detached, in which case each is capable of flight with its single wing. It is characteristic of maple seeds to whirl rapidly while falling, and if a moderate wind is blowing, they glide considerable distances. They usually fly farther than the seeds of ash although their wings are no larger. The immense numbers of seeds borne by the sugar maple insure abundant reproduction in the vicinity of parent trees. The seeds sprout readily, but often so closely crowded together that most of them die the first few weeks. Not one in ten thousand can even become a large tree, and yet large trees are exceedingly abundant in extensive regions. They often form nearly pure stands, crowding to death all rivals that try to obtain a foothold. On the other hand, this maple often contents itself with a place among other forest trees. It is one of the most vigorous and dependable of trees. It does not grow fast, but it keeps steadily at it a long time, and enjoys unusually good health. Its worst enemy is coal smoke, but fortunately, most sugar maple forests are out of reach of that disturber, though shade trees near factory towns and in the vicinity of coke ovens often suffer. Woodlots of sugar maple, occupying corners of farms in the northern states from Minnesota to Maine, present pictures of health, vigor, cleanliness, and beauty which no forest tree surpasses. The intense green and the density of the crowns in summer make the trees conspicuous in any landscape where they occur, while their brilliant colors in autumn are the chief glory of the forest where they abound. The wood of this tree is hard, strong, and dense. It is three pounds lighter per cubic foot than white oak, and theoretically it rates a little lower in fuel value, but those who use both woods as fuel consider maple worth more. It is thirty per cent stronger than white oak, and fifty-three per cent stiffer. The wood is diffuse-porous, that is, the pores are not arranged in bands or rows, as they usually are in oaks, but are scattered in all parts. They are too small to be seen with the naked eye, but under a magnifying glass they are visible in large numbers. The yearly ring is not very distinct, because of the slight contrast between spring and summerwood. The medullary rays are numerous but small. In wood sawed along radial lines, from heart to sap, small silvery flecks are numerous. These are the medullary rays. They add something to the appearance of quarter-sawed maple, but not enough to induce mills to turn out much of it.