361 JOURNAL OF FORESTRY 



tion is prolonged or renewed upon the area previously attacked. After 

 this interval the reproduction is usually too large to be seriously 

 injured. In two cases where the lumber was piled directly on the 

 ground from which it was cut, thereby attracting the beetles in larger 

 numbers, the destruction was practically complete over several acres. 

 (Observation of H. B. Pierson.) As a rule, however, the amount 

 of pine reproduction secured by thinning is so large that, even after 

 the beetles have taken a toll amounting to 75 per cent, enough remains 

 to form, with the hardwoods, a valuable stand. Furthermore, since 

 the beetles do not eat one year seedlings, cuttings made without pre- 

 vious thinning in seed years are followed by comparatively little loss. 



Injuries by the pine weevil begin usually in the small sapling stage. 

 Their chief drawback is that they check the height growth of the pine 

 at the very period when it is essential for keeping pace with the 

 hardwood. The weevil, however, is less numerous in the mixed 

 growth of cut-over lands than in pure pine plantations. Both weevil 

 and snout beetle seem, so far, beyond the reach of any effective 

 check, so that to provide more food than they can eat seems to be 

 the safest provision against them. 



WEEDING ESSENTIAL ^^'OR THE NEW CROP 



As a result of experience in the Harvard Forest nothing is clearer 

 than that the critical period for a forest is in the small sapling stage. 

 The money value of the final crop can be more greatly influenced by 

 proper treatment at this time than at any other stage of the rotation. 

 The young growth summarized in the table above, from the stand- 

 point of quantity and species, is potentially more than sufficient to 

 produce a full stand of good timber. Actually, if left to itself, it 

 will never reach a valuable maturity. The new crop, therefore, has 

 ^o be weeded, once when it is from 3 to 5 years old, and again when 

 it is from 8 to 10 years old. It is only after about 3 years that the 

 harmful effects of crowding begin to be apparent and the inevitable 

 damage to pine seedlings from snout beetles, and to hardwoods from 

 deer and rodents can be accurately discounted. After about 10 years 

 the pine and hardwoods of seedling origin have reached a uniform and 

 roughly equal rate of height growth. Meanwhile, however, the weed 

 elements in the stand will have again become dominant, so that the 

 cleaning has to be repeated. On light, sandy soils a satisfactory result 

 can be achieved with one weeding, applied in such cases after a longer 



