32 



HARDWOOD RECORD 



September 25, 1917 



Weight and Strength 



Percentage Percentage 



0/ weakest of}ightest 



Hardwoods to strongest to heaviest 



* White ash 32 59 



Persimmon 38 88 



White oak 38 69 



Hard maple 48 76 



Black walnut 51 65 



Bed oak 53 72 



White elm 55 73 



Locust 56 81 



Yellow poplar 56 79 



Basswood 58 74 



Red gum 67 89 



Cottonwood 70 67 



Beech 71 79 



Shell bark hickory 72 76 



Yellow birch 91 84 



Average 57 75 



Softwoods 



Red cedar 37 83 



Western yellow pine 37 77 



White pine 42 59 



Douglas fir . . . ; 43 62 



Longleaf pine 44 63 



Larch 48 71 



Redwood 49 59 



Hemlock 52 66 



Average 44 , 08 



It is often stated as a rule of timber physics that a wood 's strength 

 is pretty closely proportioned to its weight, when the non-essential 

 elements have been eliminated. That rule is perhaps correct, but the 

 foregoing table seems to show that woods of the same species vary 

 more in strength than in weight. The average in strength of the 

 fifteen hardwoods above is fifty-seven — that is, the fifteen weakest 

 samples had, as an average, fifty-seven per cent of the strength of 

 the fifteen strongest; but the fifteen lightest had seventy-five per cent 

 of the weight of the fifteen heaviest. The percentages for the eight 

 softwoods were respectively forty-four in strength and sixty-eight in 

 weight. 



Wood's Dorabilitt Influenced by Entironment 



The belief is quite general that the locality where a wood grows has 

 something to do with its durability. There is much evidence that this 

 belief is well founded ; but there does not seem to be so much scientific 

 information on the subject as one might suppose. Writers of books 

 on wood preservation and on the durability of timl>ers may refer 

 briefly to the effect of circumstances of growth upon the lasting 

 properties of a wood; but actual tests made by competent engineers 

 appear to be scarce. 



Nevertheless, many a farmer selects timber for fence posts upon 

 the theory that a tree's position on the top of a ridge or low in a 

 valley has much to do with the wood 's durability. Place of growth, 

 /ikewise, is credited with influencing the texture of wood ; and the 

 former abundance of that high grade white pine known as "cork 

 pine" in New England and its relative scarcity in pine regions 

 further west is pointed to as proof that the region has much to do 

 with a wood's quality. The same theory holds and seems to be 

 proved in the case of Douglas fir. That growing in the Pacific Coast 

 fog belt is commonly rated above the same species found in the dryer 

 regions of the Rocky Mountains. TJjiere is a prevailing belief among 

 manufacturers of barrels for alcoholic liquors that the white oak of 

 the wet land along the lower Mississippi is superior to the white oak 

 of the mountains on the headstreams of the Ohio rivtr. That 

 preference, however, may be due to prejudice, or it may be accounted 

 for by the fact that the mountain oak was long ago culled and the 

 best taken out, while the lowland oak has not been so culled. 



Be that as it may, the opinion that the lowland oak is the best is 

 not a new one. The following extract is interesting for the light 

 it throws on the opinion prevailing long ago.' The quotation is from 

 the writings of Edwin James in 1819, at Louisville, Ky. He says 

 of the Ohio and Mississippi river boats: 



It frequently happens that the boats built at Pittsburgh and other 

 places nc.ir the sources of the Ohio are, within three or four years after 

 they are launched, in a condition to require the planking of the hulk to 



be replaced with new timber. These boats are usually planked with 

 the upland white oak: we have been Informed that such as are built 

 lower down on the river, and of timber found on the low grounds, are 

 more durable." 



James no doubt faithfully recorded the opinion of the river boat 

 owners at that time. He was one of the foremost scientists of his day. 

 He w-as the historian of the ' ' Long Expedition to the Rocky Moun- 

 tains, " 1819 and 1820, and was on his way to Colorado when he 

 made tlie above observation on oak. He was the first white man to 

 reach the top of Pike's Peak, and was the discoverer of Long's Peak, 

 which was named for the leader of the expedition. His observations 

 are uniformly accurate and valuable, whether they relate to geology, 

 meteorology, animals, forestry, or anything else that he saw on his 

 long journey. 



Seasoning Lumber by Steam 



A large lumber company in California, which handles redwood, has 

 installed two cylinders, eachvCO feet long, and nearly seven feet in 

 diameterr, and is using them to dry lumber, about 12,000 feet to the 

 cylinder at a time. Steam is forced into the cylinders under a 

 pressure of twenty-five pounds, and that treatment forces the wood 

 to give up much of its moisture. The lumber is then taken out and 

 the seasoning may be completed in the open air, with a considerable 

 shortening of the process. 



The brief account of the operation which appeared in a recent num 

 ber of The Timberman, Portland, Ore., is not explicit as to the dura- 

 tion of the steam treatment or regarding the time required to com- 

 plete the seasoning in the open air. 



The process is not now, but this appears to be the first application 

 of the steam treatment, on a commercial scale, to the Pacific coast 

 woods. It has been tried successfully with eastern hardwoods and 

 softwoods for purely seasoning purposes, and not to soften the 

 wood to facilitate its bending. 



There has been much controversy as to just how the application of 

 steam under pressure forces the water out of the pores and cells of 

 a piece of wood. It has been argued that, since the pressure of the 

 steam is on the surface of the wood and pushing inward, it ought to 

 force moisture further into the wood instead of forcing it out; but 

 fact is bound to prevail over theory, and there is no doubting the fact 

 that some of the moisture is forced out. 



What takes place is probably this: The steam heats the moisture 

 within the wood until it is above the boiling point, and it turns to 

 steam. In changing to steam it expands several hundred fold, and 

 this expansive force drives the moisture out through small openings 

 which exist in the cells, and this expulsion is what actually reduces 

 the moisture that was in the wood when it went into the cylinder. The 

 service performed by tlie steam which enters the cylinder is to heat the 

 wood quickly. If the wood could be as quickly heated in some other 

 way, it would not be necessary to force steam into the receptacle. It 

 is heat that is needed to compel the wood to give up its moisture. 

 Doubtless the water within the wood is forced out by its own expansion 

 when it becomes heated. A piece of green wood loses some of its 

 moisture if immersed a short time in boiling water, and for precisely 

 the same reason that it loses it in a hot steam bath. 



The expulsion of water from a stick of green wood may bo witnessed 

 in full view if the stick is laid across a fire until thoroughly hot 

 within. Jets of steam may be seen issuing from the ends, often ac- 

 companied by a hissing or whistling sound. That is about what takes 

 place in a steam-heated cylinder. And it is really what occurs in a 

 dry kiln or the open air, only the process is then much slower. 



Green redwood is one of the wettest woods in the world. By weight, 

 it is more than half water, and it ought to be an ideal material for 

 seasoning in a steam cylinder, except that the wood is without pores, 

 or open channels, and the interior moisture must pass from cell to 

 cell until it reaches the surface where it can make its escape. 



Our export lumber trade to Englaurl is moving along now averaging 

 above a million dollars a month, which makes it about of normal 

 value. 



