ition of lumber and square timber, such as results from
close or solid piles, with the bottom layers on the ground or on
foundations of old decaying logs or near decaying stumps and logs,
offers especially favorable conditions for the attack of white ants.

Seasoned Products in the Rough

Seasoned or dry timber in stacks or storage is liable to injury by
powder post borers (Fig. 28). The conditions favoring attack are: (1)
The presence of a large proportion of sapwood, as in hickory, ash, and
similiar woods; (2) material which is two or more years old, or that
which has been kept in one place for a long time; (3) access to old
infested material. Therefore, such stock should be frequently examined
for evidence of the presence of these insects. This is always
indicated by fine, flour-like powder on or beneath the piles, or
otherwise associated with such material. All infested material should
be at once removed and the infested parts destroyed by burning.

Dry Cooperage Stock and Wooden Truss Hoops

These are especially liable to attack and serious injury by powder
post borers (Fig. 28), under the same or similiar conditions as the
preceding.

Staves and Heads of Barrels containing Alcoholic Liquids

These are liable to attack by ambrosia beetles (Figs. 22, _a_, and 23,
_a_), which are attracted by the moist condition and possibly by the
peculiar odor of the wood, resembling that of dying sapwood of trees
and logs, which is their normal breeding place.

There are many examples on record of serious losses of liquors from
leakage caused by the beetles boring through the staves and heads of
the barrels and casks in cellars and storerooms.

The condition, in addition to the moisture of the wood, which is
favorable for the presence of the beetles, is proximity to their
breeding places, such as the trunks and stumps of recently felled or
dying oak, maple, and other hardwood or deciduous trees; lumber yards,
sawmills, freshly-cut cordwood, from living or dead trees, and forests
of hardwood timber. Under such conditions the beetles occur in great
numbers, and if the storerooms and cellars in which the barrels are
kept stored are damp, poorly ventilated, and readily accessible to
them, serious injury is almost certain to follow.

SECTION VI

WATER IN WOOD

DISTRIBUTION OF WATER IN WOOD