ds
of treatment, and seasoning after treatment prevents the
rapid leaching out of the salts introduced to preserve the
timber.
3. The saving in freight where timber is shipped from one
place to another. Few persons realize how much water green
wood contains, or how much it will lose in a comparatively
short time. Experiments along this line with lodge-pole
pine, white oak, and chestnut gave results which were a
surprise to the companies owning the timber.
Freight charges vary considerably in different parts of the country;
but a decrease of 35 to 40 per cent in weight is important enough to
deserve everywhere serious consideration from those in charge of
timber operations.
When timber is shipped long distances over several roads, as is coming
to be more and more the case, the saving in freight will make a
material difference in the cost of lumber operations, irrespective of
any other advantages of seasoning.
Prevention of Checking and Splitting
Under present methods much timber is rendered unfit for use by
improper seasoning. Green timber, particularly when cut during
January, February, and March, when the roots are most active, contains
a large amount of water. When exposed to the sun and wind or to high
temperatures in a drying room, the water will evaporate more rapidly
from the outer than from the inner parts of the piece, and more
rapidly from the ends than from the sides. As the water evaporates,
the wood shrinks, and when the shrinkage is not fairly uniform the
wood cracks and splits.
When wet wood is piled in the sun, evaporation goes on with such
unevenness that the timbers split and crack in some cases so badly as
to become useless for the purpose for which it was intended. Such
uneven drying can be prevented by careful piling, keeping the logs
immersed in a log pond until wanted, or by piling or storing under an
open shed so that the sun cannot get at them.
Experiments have also demonstrated that injury to stock in the way of
checking and splitting always develops immediately after the stock is
taken into the dry kiln, and is due to the degree of humidity being
too low.
The receiving end of the kiln should always be kept moist, where the
stock has not been steamed before being put into the kiln, as when the
air is too dry it tends to dry the outside of the stock first--which
is termed "case-hardening"--and in so doing shrinks
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