beveled or scarped to a thin edge since it will be
a. Deciduous and coniferous trees are
subject to tension only. A fishplate or scab can be
found in temperate climates and make good
fastened along the bottom of the splice to resist the
When cut into lumber,
tendency of the pieces to separate there.
deciduous trees produce hardwoods and coniferous
trees softwoods. Although no definite degree of
1-10. TYPES OF WOOD
hardness divides the two groups, woods in the
hardwood category are of higher density than those
A knowledge of the kinds and physical
classified as softwoods. Hardness is measured by the
characteristics of wood will aid the engineer officer
compression which a piece of timber can withstand
to correctly use this building material which is the
when a weight is applied to it. Oak, maple, hickory,
basis of most TO construction. We may classify
elm, beech, ash, and locust are representative
timber initially in four broad categories according to
the nature of growth:
are pine, fir, cedar, spruce, hemlock, cypress, larch,
Deciduous - broad-leafed trees which shed
and redwood. In TO construction the Army uses
mainly softwoods, principally because they are easier
to work, lighter in weight per unit volume, less
Coniferous - needle-leafed trees.
expensive, and, in general, more available.
b. Bamboo and palm trees are found in
tropical climates, and in some respects are
Figure 1-12 presents typical characteristics of wood
and its uses.
Figure 1-12. Lumber and its uses.