Timber: an elementary discussion of the characteristics and properties of wood by Roth Filibert 1858-1925

Author:Roth, Filibert, 1858-1925. [from old catalog]
Language: eng
Format: epub
Tags: Wood
Publisher: Washington, Govt. print. off.
Published: 1895-03-25T05:00:00+00:00

(H«rtlg)

light

esyed woot or pu k il laf«r ot ] ng aporu t b«B r old Ulled paporel bu / d ted npiwr (urrace ot Ihe rru t ng

'»dj- of Ihe fungo*, whitt gatA ilA food through a great number uf Bn« tbreada (the inycelinm), iu vegeUtive 11b-■ ue penetratiag thowoodaud

discernible.

Cutting yflf a disk of loblolly pine, wnshing it, and then laying it in a clean, shady place in the sawmill, its sapwooil will be found stained in a few days. Nor is this mischief confined to the sur- <■"•*•"» •^•'•••'•^• face; it penetrates tbe sapwood of the entire disk. From this it appears that the spores must ha,ve been in the air about tbe mill, and also that their germination and tbe growtli of the threads or mycelium is exceedingly rapid. (Watching tlie progress of mold on a piece of bread teaches the same thing.) Placing a fresli piece of sapwood on ice, another into a dry kiln, and soaking a few others iu solutions of corrosive sublimate {mercuric chloride) nnd other similar salts, we learn that the fungus growth is retarded by cold, prevented and killed by temperatures over 150° F,, and that salts of mercury, etc., have the same effect. The fact that seasoned pieces if exposed are not so readily attacked by fungi shows that tbe moistnre in air-dry wood is insufficient for

Uio* break down the wood fungUS grOWth.

fltmctnre. From this.it appears that warmth, preferably

between 60o and 100° F., combined with abuntlance of moisture (but not immersion), is the most important condition favoring decay, and that the defense lies in the proper regulation or avoidance of these

Fid. 3S.--FiingD« Ibreadi li pine wood, (Hartlg.) a ceU wall of tbe wood fibers

In tbe oell wall* n» tbe fUDKua threada, gradiull; diaaolve

TIHBEB.

conditions, or else in the use of poisonous salts, ■which prevent the propagation of fangi.

It is also apparent, therefore, why wood decays faster iu Alabama tlian in Wisconsin, faster in the swamps than on the plains, and wby the presence of large quantities of decaying wooil about the yard, constantly producing fresli suppUes of spores, stimulates decay. Covering with tar or impregnating with creosote, salts of mercury, copper, etc., enables even sap-wood to last under the most trying conditions. Contact with the I iS ground assures most favorable moisture conditions for fungus growth, and the higher temperatures near the surface of the ground, together with the ever-present supply of 8i>ore8, cause rot in a post to start at the surface more readily than 30 inches below.

The use of means to prevent decay is therefore desirable where timber is placed iu positions favorable to fungus growth, as in railway ties; and all joists and timber in contact with damp brick walls, as also all building material whose perfect seasoning is prevented by the absence of proper circulation of air, should be specially protected. In the former cases it is economy to apply preservative processes; in the latter a sanitary necessity. Wood covered with paint, etc., before it is perfectly seasoned,

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