eam or heat in a dry kiln), checks or splits more
or less. This is due to the uneven drying-out of the wood and the
consequent strains exerted in opposite directions by the wood fibres
in shrinking. This shrinkage, it has been proven, takes place both
end-wise and across the grain of the wood. The old tradition that wood
does not shrink end-wise has long since been shattered, and it has
long been demonstrated that there is an end-wise shrinkage.

In some woods it is very light, while in others it is easily
perceptible. It is claimed that the average end shrinkage, taking all
the woods, is only about 1-1/2 per cent. This, however, probably has
relation to the average shrinkage on ordinary lumber as it is used and
cut and dried. Now if we depart from this and take veneer, or basket
stock, or even stave bolts where they are boiled, causing swelling
both end-wise and across the grain or in dimension, after they are
thoroughly dried, there is considerably more evidence of end
shrinkage. In other words, a slack barrel stave of elm, say, 28 or 30
inches in length, after being boiled might shrink as much in
thoroughly drying-out as compared to its length when freshly cut, as a
12-foot elm board.

It is in cutting veneer that this end shrinkage becomes most readily
apparent. In trimming with scoring knives it is done to exact measure,
and where stock is cut to fit some specific place there has been
observed a shrinkage on some of the softer woods, like cottonwood,
amounting to fully 1/8 of an inch in 36 inches. And at times where
drying has been thorough the writer has noted a shrinkage of 1/8 of an
inch on an ordinary elm cabbage-crate strip 36 inches long, sawed from
the log without boiling.

There are really no fixed rules of measurement or allowance, however,
because the same piece of wood may vary under different conditions,
and, again, the grain may cross a little or wind around the tree, and
this of itself has a decided effect on the amount of what is termed
"end shrinkage."

There is more checking in the wood of the broad-leaf (hardwood) trees
than in that of the coniferous (softwood) trees, more in sapwood than
in heartwood, and more in summer-wood than in spring-wood.

Inasmuch as under normal conditions of weather, water evaporates less
rapidly during the early seasoning of winter, wood that is cut in the
autumn and early winter is considered less subject to checking than
that which is cut in spring and summer.