494 



JOUKXAL OF FORESTRY 



ferior trees, such as gray birch and poplar or poorl\- formed specimens 

 of the better species. 



This kind of deterioration is so wide-spread in second-growth forests 

 and represents such an apparently preventable loss that it deserves 

 analysis as an important problem of forest management. Tlie purpose 

 of this paper is to present the results of certain experiments, computa- 

 tions, and silvicultural experiences bearing on the practical possibility 

 of increasing the final value of such forests by early weedings or im- 

 provement cuttings. In order to make comparisons significant, the 



Fig. I. — Even-aged stand mixed pine and hardwoods forty years old 



Over 1,500 sapling white pines per acre dead or suppressed under weed species or 



worthless sprouts 



study was limited to the same general association of species, namely, 

 such second-growth forest on cut-over lands as had originated with 

 (potentially) enough both pine and desirable hardwood reproduction 

 to be fairly called a mixed pine and hardwood type. The data and 

 material presented were all gathered on or near the Harvard Forest, in 

 northern Worcester County, Massachusetts. This locality, though situ- 

 ated in the main white-pine belt of the State, is characterized also by a 

 considerable number of hardwood species, due in part to a somewhat 

 heavy soil and in part to being in a transition zone between northern 

 and central forest types. The topography is, in general, a rolling up- 



