16 .lOrRXAL OK l*()Ki:STKV 



Three temporary sample plots, each 40 feet hy 100 feet, were estab- 

 lished on the r>lake lot. where the birch and other hardwoods were 

 removed from over the pine in the winter of 1917-18. Each plot was 

 representative of different degrees of density of the overwood as de- 

 termined by the number and diameter of the stumps. Plot I had the 

 least degree of density: Plot II intermediate, while Plot III had the 

 greatest degree of density. The problem was to ascertain, if possible, 

 the effect of the liardwoods, chiefly gray birch, on the density of the 

 white pine and on its rate of growth. On all three plots the birch 

 and other hardwoods were 24 years old. and for the most part from 

 sprouts following a clear cutting. The average height of the canopy 

 prior to cutting the hardwoods was approximately 28 feet, as deter- 

 mined by adjacent stands of the same age as yet uncut. 



Reducing the data derived from the sample plots to an acre basis. 

 Plot I, with the least degree of density of hardwoods, had 610 hard- 

 wood stumps per acre from one to six inches in diameter, with gray 

 birch forming practically all of the larger sizes. The white pines freed 

 by the removal of the hardwoods were 1,230 per acre, for the most 

 part of the same age as the overwood removed. Many of these pines 

 extended up into the hardwood canopy, and in time would have out- 

 stripped the hardwoods and formed a practically pure pine stand. 

 Under this density of hardwoods, chiefly gray birch 24 years of age, 

 the number of pine was adequate for a fully stocked stand and had 

 from the beginning made a very satisfactory growth, as but 2,'/2 out of 

 1,230 per acre were under eight feet in height. Although the tops of 

 some were badly whipped by the birch, the removal of the hardwoods 

 was not necessary in order to prevent loss due to shading or marked 

 decrease in growth. 



Plot II, with an intermediate density of hardwoods, chiefly gray 

 birch, when reduced to an acre basis had 2,198 hardwood stumps per 

 acre, one to six inches in diameter. The white pines freed by the re- 

 moval of the hardwoods and with only a relatively small number 

 reaching up into the birch canopy, were 2,428 per acre. They were 

 with few exceptions of the same age (24 years) as on Plot I. .Vo 

 pines were found that had been killed by competition 7i.nth the over- 

 wood. Those less than two feet in height were as old as those eight 

 or ten feet tall. The denser overwood had no apparent effect upon 

 the density of pine beneath its canopy, but compared with Plot I the 

 pine was much smaller and more slender. The foliage was less and 

 much more open. The chief effect of the increased density of the 

 birch overwood was to restrict the rate of height growth of the pines 

 and give them the appearance of being much less robust. Under a 



