oF, THE FORESTS OF THE UNITED STATES: THEIR USE. 
PRESERVATIVE TREATMENT OF TIMBER. 
Of all the wood in every form now in use in the United States, 
decay, fire, insects, and salt-water borers destroy not less than the 
equivalent of 8,000,000,000 board feet each year. Of these, decay is 
far the most destructive. It is also the easiest to retard. The pre- 
servative treatment of timber will lengthen by ten to twenty years 
the life of woods now commonly used for posts, poles, ties, mine tim- 
bers, bridge timbers, and for much other construction work. It will 
also make profitable the use of many woods which untreated, decay so 
quickly that they have little or no value. If preservative treatment 
makes the life of timber in use twice or three times that of untreated 
timber, only one-half or one-third as much timber is consumed by 
that use. Nor does this take into account that large saving in the 
labor of replacing decayed timber, which in the maintenance of rail- 
road tracks, using untreated ties, is about one-third the cost of the 
new ties used each year, to keep the track in condition. 
In 1907, 1,250,000,000 board feet of timber were treated, which was 
not more than one-quarter the quantity which could have been treated 
with profit to its users. There are about 700,000,000 ties in railroad 
tracks in the United States. They represent, untreated, an average 
cost per tie of about 12 cents a year. If all were treated, the increase 
in their length of service would mean a saving of 2.3 cents per tie 
per year, or a total annual saving of about $16,000,000. More than 
$2,000,000 could be saved each year by treating all the poles, and 
nearly $2,000,000 if all the piling were treated. The saving in tim- 
ber used in the mines would be about $12,000,000. If lumber so 
exposed in use that treatment is profitable were treated, the saving 
would not be less than $15,000,000. This means a total practicable 
saving of over $47,000,000 a year. It means also that the increased 
life given these timbers would make an annual saving in wood equiva- 
lent to 4,000,000,000 board feet, or 10 per cent of the yearly lumber 
cut. 
Two preservatives are widely used in the United States. These are 
creosote and zine chlorid. The chief advantage of creosote is that 
once injected into wood it prevents decay permanently. Its chief dis- 
advantages are its cost and scarcity. Zinc chlorid is cheaper and an 
excellent antiseptic. But it will leach out if the treated wood is 
exposed to moisture. 
A farmer can treat a fence post with creosote for about 10 cents 
and make it last twenty years. Apparatus costing from $50 to $75 
will treat from 50 to 100 posts a day, depending upon the kind of 
timber. The butt of a 20-foot telephone pole can be treated for from 
75 cents to $1. The plant will cost from a few hundred to several 
thousand dollars, depending upon its capacity. Piling properly 
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