HARDWOOD RECORD 



29 



What iloes happen is the depositiou of varying amounts of resins, 

 tannin, pigments, gums and other substances. The resin or pitch 

 of pine and other softwood trees becomes oxidized into rosin, 

 which is extremely durable. Most of these substances are in the 

 cell walls, but some of them may fill up the cavities as well. It 

 is to these that heart-wood owes its greater ability to resist decay, 

 for they protect it for a time at least against the attacks of fungi. 

 Later, as the substances leach out or are chemically changed, the 

 wood slowly rots. 



It is generally true that depth of color is a safe guide to the 

 durabilit}' of wood. Thus the dark heart-wood of red cedar, 

 mesquite, redwood, Osage orange, black locust, mulberry, and 

 lignum-vitsB is very resistant to decay, while that of willow, bass- 

 wood, buckeye, gum, tupelo, maple, ash, and cottonwood is perish- 

 able. In some instances, however, as in northern white cedar, 

 sassafras, Lawson 's cypress, and yellow cedar, the infiltrated sub- 

 stances tend to prevent decay without greatly deepening the color 

 of the heart-wood. The fatty stumps and knots of pine trees 

 remain in the woods for years after every other trace of the tree 

 has disappeared. The natives esteem old snags of this kind for 

 gate posts and the knots for fuel. In fact in certain portions of 

 the South fat pine or lightwood is largely relied upon for lighting 

 the humble cabins of the mountaineers. 



There are other forms of life besides fungi and bacteria which 

 affect the durability of wood. Piling and wharf timbers and wood 

 kept under water at shipping points aie subject to the attacks 

 of certain animals, principal of which are the teredos. These are 

 mollusks which live only in salt water and bore not only the sap- 

 wood but also the heart-wood of nearly every kind of timber. 

 Ships, the bottoms of which are not covered with copper, suffer 

 greatly from teredos. The question of protecting such timbers 

 by thorough impregnation with creosote, studding with nails, and 

 covering with different compositions is still demanding much 

 attention and forms the subject of numerous experiments. 



Poles and posts are subject to attacks of insects and borers 

 which may prove more serious than fungi. In fact, the two are 

 often closely associated. The presence of bark offers a good place 

 for the hiding and development of insects and adds greatly to the 



danger of attack, llanufactured articles may be entirely destroyed 

 bj' the larvEe of powder-post beetles which honeyeoml) tie wood 

 and reduce it to powder. In tropical countries the danger from 

 ants is one of the most serious to which wooden straiSSfeTes are 

 subjected, but in temperate regions this trouble is small. 



In many uses of wood abrasion and wear of different kinds are 

 of more significance than damage from any other source. For 

 instance, chestnut is rated as a durable timber and is much cut 

 for railroad ties. On the Pennsylvania railroad such ties are 

 confined to the sidings on the main lines and to unimportant 

 branches. Local conditions affect the general policy. For example, 

 on the Pittsburgh division it is necessary to import white oak 

 ties from West Virginia and Kentucky, since that species is not 

 produced in sufficient quantity along the division. Chestnut is 

 used along the west-bound freight tracks because tli«5f<siipply is 

 abundant and also because that track carries empties mostly. On 

 the main line the high-speed traflic would cut out a chestnut tie 

 in one year. In stone ballast and under lighter traffic such a tie 

 will last about four years. As ordinarily used such ties are in 

 cinder ballast and last from ten to twenty years. Last spring 

 there were removed from the Tongascootae branch chestnut ties 

 that had been there for eighteen years. A few on the Delaware 

 division have lasted twent.y-eight years. 



Knowledge of the factors affecting durability is essential if 

 one would secure the longest life of material. It emphasizes the 

 importance of keeping material dry; it points the way to artificial 

 durability by the use of oils, paints, and preservatives for exclud- 

 ing moisture, closing up entrances for disease spores, or poisoning 

 the food supply for destructive forms of life. It is not always 

 sufficient that artificial means be employed for preserving wood 

 from natural enemies, for it must be protected from jiiechanical 

 wear as well. It would be poor business, for instance, to creosote 

 a tie to make it immune from rot for twenty years and then from 

 lack of tie plates, or screw spikes, or proper ballast, or because 

 subjected to too severe conditions, have it worn out in a fraction 

 of that time. 



In conclusion, it might be addeil that there is no ' ' wood 

 eternal. ' ' S. .J. R. 



\ i y^aiSiK;:;^ ' ^;-sroTO6cratoiH!;u^Ki>twy;;^^^ 



Crahivood and Its Uses 



t'rabwood (Carapa guiancnMs-Aubl.) is a large tree found in 

 Trinidad, Colombia, Venezuela, the Guianas, and Brazil. It is 

 commonly known as carapa, or, by corruption, crapaud or crappo, 

 andiroba, angiroba, and nandiroba. This tree is confined chiefly 

 to the dense forests along the rivers, where its timber is obtain- 

 able in sticks up to fifty feet in length and from fifteen to twenty 

 inches square. It grows very abundantly along the Demerara 

 river in British Guiana, and accordingly is often called Demerara 

 mahogany in this country. In the English markets it is known 

 chiefly as erabwood. Its principal place of export is Georgetown, 

 British Guiana. 



In grain, strength, color, and specific gravity, the wood appears 

 to be intermediate between Spanish cedar {Cedrela odorata-Linn.) 

 and mahogany (Swietenia mahogoni-Ja.eq.) . In general appear- 

 ance it reminds one somewhat of an open-grained grade of ma- 

 hogany and at times is sold and even placed on the large markets 

 for that wood. Cedar, however, is a much lighter wood, its 

 specific gravity being AH, erabwood showing .689, while true 

 mahogany is sometimes as high as .806. Crabwood is not very 

 strong, but is quite tough, moderately heavy, durable, and has a 

 pleasant brown color, rather dark, with a grain somewhat more 

 open than that of genuine mahogany. It is said to warp, check 

 and often twist in seasoning. These defects are usually observed 

 and not being characteristic of true mahogany, the purchaser's 

 suspicion is at once aroused, and upon inquiry is informed that 

 his Demerara mahogany is not mahogany at all, but is crabwood. 



The pith rays of crabwood are quite numerous, but very narrow, 

 so that the wood when quarter-sawed does not show any very 

 remarkable figure and probably is quite as handsome flat-sawed 

 as quarter-sawed; in the opinion of some it is handsomer. The 

 wood has another advantage over a number of mahogany sub- 

 stitutes, which adds to its value, in that it is easily worked. 

 This qualit}', combined with its rather pleasing color, ought to 

 commend it for inside finish as well as for cabinet-making. It 

 has been used quite extensively for that purpose in England for 

 a good many years, and just now when the favorite woods are 

 rather costly, crabwood should make a valuable addition to the 

 list of inside finishing woods of the better class. 



While crabwood is generally recognized among furniture men 

 as an inferior grade of cabinet wood, it is nevertheless employed 

 for making the less expensive furniture. AlthougK its natural 

 color is quite pleasing, it is usually stained and darkened more 

 or less so that one can not deny that it makes pretty fancy 

 looking furniture. It is a good serviceable wood and deserves to 

 be placed on the market under its own name instead of being 

 palmed oft" as mahogany. Crabwood possesses many really good 

 qualities and it may be recommended not only to the cabinet 

 maker but also to the builder of small means, who wishes a 

 substantial hardwood for interior finish. The wood has an ex- 

 tensive use in the region where it grows. It is sawn into scantling, 

 boards, and planks, and is split into shingles and staves. Its chief 

 native use is for beams, rafters, and for furniture. C. D. M. 



