504 JOURNAL OF FORESTRY 



wood stump sprouts at one end and the white-pine seedlings at the 

 other, there will be a large amount of other seedling and sapling repro- 

 duction, as shown in Table i, much of the best of which will be nearer 

 the normal rate of white pine than the excessive rankness of the sprouts. 

 If the best results in the form of final value are to be achieved, it is 

 plain that the first weeding must be applied earlier than the sixth year, 

 since by that time suppression of the more valuable elements in the 

 crop is already well under way. On the other hand, if the first weeding 

 is made too early, the smallness of many of the seedlings and the rank- 

 ness of herbaceous growth may render impossible a proper recognition 

 of the true composition and promise of the crop. In addition to the 

 most favorable date for the first weeding, it is also highly important for 

 the forest manager to know how often and how many times the opera- 

 tion will have to be repeated. The proper date for the first weeding 

 should coincide with the time when the reproduction is large enough to 

 be fully recognizable in detail (i. e., as to species and condition) and 

 before any of the more valuable trees have begun to be seriously sup- 

 pressed. Experience on the Harvard Forest indicates that this time is 

 during the third or fourth year. The frequency with which the crop 

 will have to be treated depends both on its composition — that is, how 

 vigorous and numerous the desirable trees are in comparison wdth the 

 undesirable — and, second, on the quality of the locality. The better the 

 site the more rapid and persistent will be the growth of the hardwoods 

 that must be eliminated. The general object should be to maintain the 

 largest possible proportion of valuable trees in favorable growing con- 

 dition until they have reached a size and rate of height growth that will 

 enable them to keep even with or ahead of the weed element in the 

 stand. 



Table 7. — Current Height Growth for last Two Years in Even-aged Sapling 

 Stand Eight Years Old and Twice Weeded 



Species 

 in mixture 



White pine i . 



White ash 



Red oak 



Sugar maple 



Red maple 



Black cherry 



Chestnut 



Paper birch 



Gray birch 



Based on measurements of 245 trees. Average number per acre, 2,500. 

 Average height, 6.4'; range of height, 4.2' to 11'. Quality, I. 



