. An annotated list of the important North American forest insects. Forest insects. BULLETIN 1490, U. S. DEPARTMENT OF AGRICULTUEE The rejection of timber with insect defects caused in the tree, log, or green lumber before the wood is dry or seasoned is often an avoidable loss, because the insects are no longer working in the wood. This type of insect defect is analogous to " pecky^ cypress " caused by a fungus. Even though the defects are such that they materially affect the strength of the wood or otherwise unfit it for the special use intended, there are still many purposes for wh
. An annotated list of the important North American forest insects. Forest insects. BULLETIN 1490, U. S. DEPARTMENT OF AGRICULTUEE The rejection of timber with insect defects caused in the tree, log, or green lumber before the wood is dry or seasoned is often an avoidable loss, because the insects are no longer working in the wood. This type of insect defect is analogous to " pecky^ cypress " caused by a fungus. Even though the defects are such that they materially affect the strength of the wood or otherwise unfit it for the special use intended, there are still many purposes for which it can be used. The grade may be merely lowered, according to the number and size of the holes; or the defect may unfit the wood for special uses, owing to unsightly appear- ance, likelihood to cause leaks (as for barrel staves and heads for tight cooperage), or weak- ening (as for high-grade air- plane stock). Much waste can be avoided by utilizing such defective timber for other uses and in lower grades than origi- nally intended. Damaged implement or ve- liicle stock and other material in which great structural strength is required can be used for less exacting purposes, the defect being plugged and painted over; while low-grade lumber with wormholes but no living worms or decay can be used as the base for veneer if the holes are not large enough to cause depressions in the face veneer. On the other hand, the acceptance of material infested by powder-post beetles may lead to serious results through a break at a critical moment. Special reference is made in this bulletin to the protection and conservation of both crude and finished wood products, such as lumber, bolts, cooperage stock (finished and unfinished), agricultural- implement handles, tent poles, vehicle parts, timber for shipbuilding, oars, airplane stock, and other high-grade products. TYPES OF INSECT DEFECTS; DEFINITIONS The principal types of defects caused by insects may be classed in three definite groups,
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