One of the major limiting factors affe 

 white pine weevil. This insect attacks 

 of the tree. The resulting injury 

 lateral branches competing for the posit 

 leader inevitably produce a crook in 

 quality. The rapidity with which one la 

 the others determines the degree of 

 long enough to establish a forked tree, 

 injury also causes a loss in stem len 

 Lumber defects caused by weevil injury a 

 knots, and loose knots. 



cting the quality of white pine is the 

 and kills the terminal (central) shoot 

 seldom causes deaths of the trees, but 

 ion formerly held by the terminal 



the stem, which ultimately lowers log 

 teral shoot asserts its dominance over 

 the crook. Often two laterals compete 



In addition to causing crooks, weevil 

 gth, affecting 2 or 3 years of growth, 

 re cross-grain, red rot, large branch 



Several techniques are used for controlling white pine weevil damage. 

 Chemical sprays can be used safely provided that precautions are observed with 

 applications and dosage, and that only properly registered insecticides are 

 used. Spraying from the ground is expensive and aerial spraying in the spring 

 has not proved successful. Recent research performed on young white pine 

 plantations in Penobscot County by the University of Maine's School of Forest 

 Resources indicates that fall spraying may offer promise to greatly reduce 

 insect numbers (Cooperative Forestry Research Unit 1979). 



10 20 30 40 50 60 70 

 BREAST-HEIGHT AGE (YEARS) 



80 



90 100 



Figure 19-2. 



Site index curves for eastern white pine in New England 

 (curves corrected to breast-height age of 50) (Frothingham 

 1914). 



19-20 



