INSECT DEPHEDATIONS IN NORTH AMERICAN FORESTS. 61 



moro or loss affected, and a lar<i:e pcrconlafre is so seriously daniafjed 

 that tile j)rodiicl is reduced to that of the lowest "friide. It is esti- 

 mated that the I'cihict ion in value of the average liunlx'i- |)ro(liict at 

 any n^iven time is not far from ;'.() per cent, thus involving; extensive 

 waste and an increased drain on the forest to sujiply the recpiire- 

 ments for clear lumber. This insect also attacks the oaks, and 

 especially the red oak, the older lree> of which are often as seri- 

 ously dama<red as are the chestnut. (Hopkins, 1894^/, 1!»04A.) 



Carpenter tcorm.s. — The oaks, especially the white oak and the led 

 oak, are seriously dama<re(l by carpenter worms of the <i:enus Prion- 

 oxystus. The holes made by these insects throuirh the heartwood of 

 the best part of the trunks are .sometimes 1..") inches in diameter one 

 way by 0.75 inch the other, thus causing; serious dama^^e to the wood. 

 These, with other lar<re wood-borinj^ beetle larvie, sometimes infest 

 the toj) i)art of the trunk and the larger branches of oak trees, where 

 their continued work results first in the dead and so-called "stag- 

 horn ■' top and subsequently in broken, decayed, and worthless 

 trunks. (Hopkins, 1894fl, 19b4/>.) 



Amhro.sia beetles. — One of the commonest defects in white oak, rock 

 oak, beech, whitewood or yellow poplar, elm, etc., is that known to the 

 lumber trade as " grease spots,"' " patch worm," and " black holes." 

 This defect is caused by one of the timber beetles or ambrosia beetles, 

 Coi'f/ii/Ji/.s eohimhianiis Ilopk., which makes successive attacks in the 

 living healthy sapwood from the time the trees are '10 or :^0 years 

 old until they reach the maxinnnn age. Thus the l)lack-hole and 

 stained-wood defect is scattered all through the wood of the best 

 part of the trunks of the trees. The average reduction in value 

 of otherwise best-grade Imnber amounts, in many localities, to from 

 25 to 75 \wv cent. The defect is conunoidy found in oak and elm 

 furniture and in interior hardwood finish in dwellings and other 

 buildings. (Hopkins, 180.V/, 18n4?>, 1004A.) 



The loriisf horcr. — The locust, as is well known, suffers to such an 

 extent from the ravages of the locust borer {('yllene rohinn- Forst.) 

 that in many localities tlie trees are rendered worthless for commei'cial 

 ])ur|)oses or (hey are reduced in value below tiie point of profitable 

 growth as a foi'cst tree, otherwise this would be one of ! he niosi piojit- 

 able trees in the natural forest or artificial plantnlion and would c(tn- 

 tribute greatly to an increased timber supply. ( lloplxin-. \'M)\\I,, 

 1907r/, l!»r)7r.) 



Turpentine heetlex and turpentine txtvers. — ^^'hile the softwood 

 trees, or conifers, suffer far less than the hardwoods from the class 

 of enemies which cause defects in the living timber there are a 

 few notable examples of serious damage. There is a connnon trouble 

 affecting the various sj)ecies of jiine throughout the country known 

 as basal wounds or basal fire wounds. It has been found that a large 



