INSECT DEPREDATIONS TN NORTTT AMERTCAX FORESTS. 61 



more or loss aftVctctl, and a laiirc j)('i\'onta<;e is so seriously dainaf^cd 

 that the |)i-odiict is reduced to that of the lowest <j:i-ade. It is esti- 

 luafeti that the rr(hicti()ii in \ahie (d" the a\'era^"e huul»er proihict at 

 any <iiven time is not far from 'M) pcv cent, thus invoUini; extensive 

 waste and an increased drain on the forest to sui)ply the re<|uire- 

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

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

 ously damaged as are the chestnut. (Hopkins, 18i)4f/, VJOAh.) 



Carpenter icoimis. — The oaks, especially the white oak and the red 

 oak, are seriously daina<>;ed by cari)enter worms of the <renus Prion- 

 oxystus. The holes made l)y these insects throuLdi 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 damaire to the wood. 

 These, with other lari>:e wood-boring beetle larvie, sometimes infest 

 the top part 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. ' (Iloi)kins, 1894«, ll)'o4/y.) 



Anihrosia hcctles. — One of the connnonest defects in white oak. rock 

 oak, beech, whitewood or j'ellow poplar, elm, etc., is that known to the 

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

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

 Coi'tln/Jns cohimhianiift Ilopk., which makes successive attacks in the 

 living healthy sapwood from the time the trees are 20 or 30 years 

 old until they reach the maxinnun 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 lumber amounts, in many localities, to from 

 25 to 75 j)er cent. The defect is connnonly found in oak and elm 

 furniture and in interior hardwood finish in dwellings and other 

 buildings. (Hopkins, 1803.v, 18047>, 1004/>.) 



7^ he Jo( ust barer. — The locust, as is well known, sulfers to such an 

 extent from the ravages of the locust borer {('yllene rohhu(v Forst.) 

 that in many localities the trees are rendered worthless for commei-cial 

 purposes or they are reduced in value below the i)()int of i)rolital>le 

 growth as a forest tree, otherwise this would l>e one of the most proht- 

 able trees in the natural forest or artificial |)l:inlation and would con- 

 tribute greatly to an increM-e<] (imber supply. (IlopUin-. I'.MIC./;, 

 1907^/, ll>07r.) 



Turpentine hertlefi iin<I inr^n ni'ine Ixinrs. — Wiiile 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. Tln're is a connnon troul)le 

 affecting the various species of ])ine throughout the country known 

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



