other. Where the rings are extremely narrow, the dark portion of the
ring is often wanting, the color being quite uniform and light. The
greater regularity or irregularity of the annual rings has much to do
with the technical qualities of the timber.

Spring- and Summer-Wood

Examining the rings more closely, it is noticed that each ring is made
up of an inner, softer, light-colored and an outer, or peripheral,
firmer and darker-colored portion. Being formed in the forepart of the
season, the inner, light-colored part is termed spring-wood, the
outer, darker-portioned being the summer-wood of the ring. Since the
latter is very heavy and firm it determines to a very large extent the
weight and strength of the wood, and as its darker color influences
the shade of color of the entire piece of wood, this color effect
becomes a valuable aid in distinguishing heavy and strong from light
and soft pine wood.

In most hard pines, like the long-leaf, the dark summer-wood appears
as a distinct band, so that the yearly ring is composed of two sharply
defined bands--an inner, the spring-wood, and an outer, the
summer-wood. But in some cases, even in hard pines, and normally in
the woods of white pines, the spring-wood passes gradually into the
darker summer-wood, so that a darkly defined line occurs only where
the spring-wood of one ring abuts against the summer-wood of its
neighbor. It is this clearly defined line which enables the eye to
distinguish even the very narrow lines in old pines and spruces.

In some cases, especially in the trunks of Southern pines, and
normally on the lower side of pine limbs, there occur dark bands of
wood in the spring-wood portion of the ring, giving rise to false
rings, which mislead in a superficial counting of rings. In the disks
cut from limbs these dark bands often occupy the greater part of the
ring, and appear as "lunes," or sickle-shaped figures. The wood of
these dark bands is similar to that of the true summer-wood. The cells
have thick walls, but usually the compressed or flattened form.
Normally, the summer-wood forms a greater proportion of the rings in
the part of the tree formed during the period of thriftiest growth. In
an old tree this proportion is very small in the first two to five
rings about the pith, and also in the part next to the bark, the
intermediate part showing a greater proportion of summer-wood. It is
also greatest in a disk taken from n