The Mechanical Properties of Wood: Including a Discussion of the Factors Affecting the Mechanical Properties, and Methods of Timber TestingRecord, Samuel J. (Samuel James)
Science
The Mechanical Properties of Wood: Including a Discussion of the Factors Affecting the Mechanical Properties, and Methods of Timber Testing
Record, Samuel J. (Samuel James)
Wood; Wood -- Testing
" ... It is clear that as all localities have their heavy and
their light timber, so they all share in strong and weak, hard
and soft material, and the difference in quality of material is
evidently far more a matter of individual variation than of soil
or climate." _Ibid._, p.22
"A representative committee of the Carriage Builders'
Association had publicly declared that this important industry
could not depend upon the supplies of southern timber, as the
oak grown in the South lacked the necessary qualities demanded
in carriage construction. Without experiment this statement
could be little better than a guess, and was doubly unwarranted,
since it condemned an enormous amount of material, and one
produced under a great variety of conditions and by at least a
dozen species of trees, involving, therefore, a complexity of
problems difficult enough for the careful investigator, and
entirely beyond the few unsystematic observations of the members
of a committee on a flying trip through one of the greatest
timber regions of the world.
"A number of samples were at once collected (part of them
supplied by the carriage builders' committee), and the fallacy
of the broad statement mentioned was fully demonstrated by a
short series of tests and a more extensive study into structure
and weight of these materials. From these tests it appears that
pieces of white oak from Arkansas excelled well-selected pieces
from Connecticut, both in stiffness and endwise compression (the
two most important forms of resistance)." Report upon the
forestry investigations of the U.S.D.A. 1877-1898, p. 331. See
also Rep. of Div. of For., 1890, p. 209.
"In some regions there are many small, stunted hickories, which
most users will not touch. They have narrow sap, are likely to
be birdpecked, and show very slow growth. Yet five of these
trees from a steep, dry south slope in West Virginia had an
average strength fully equal to that of the pignut from the
better situation, and were superior in toughness, the work to
maximum load being 36.8 as against 31.2 for pignut. The trees
had about twice as many rings per inch as others from better
situations.
"This, however, is not very significant, as trees of the same
species, age, and size, growing side by side under the same
conditions of soil and situation, show great variation in their
technical value. It is hard to account for this difference, but
it seems that trees growing in wet or moist situations are
rather inferior to those growing on fresher soil; also, it is
claimed by many hickory users that the wood from limestone soils
is superior to that from sandy soils.
Public-domain text, read in full here on John Shaqi.
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