378 JOURNAL OF FORESTRY 



Table for Plot No. 2 



Before After Before After 



Thinning Thinning Thinning Thinning 



27 Years 30 Years 



Number trees per acre 1,369 1,066 1,066 660 



Basal area, sq. ft. per acre 141.1 119.9 145.6 104 



Average diameter, inches 4.3 4.5 5.0 5.4 



Average height, feet 36.6 36.7 43.2 44.7 



Volume, cu. ft. per acre 2,852.6 2,426.8 2,954.1- 2,165.3 



The mean annual growth after the first thinning was 155 cubic 

 fe'et per acre as against 105 cubic feet before the thinning, and the 

 current annual 175.4 cubic feet per acre. The current annual growth 

 will undoubtedly increase rapidly as soon as the effect of the thinnings 

 is felt. The thinning at 27 years of age removed 22.1 per cent of the 

 trees and 14.9 per cent of the volume; it increased the average 

 diameter by .2 of an inch and the average height by .1 of a foot. 

 The thinning at 30 years of age removed 38 per cent of the number 

 of trees and 26.7 per cent of the volume; the average diameter was 

 increased by A of an inch and the average height by 1.5 of a foot. 

 The basal area and the volume after the thinning increased in the 

 three years 21 per cent. 



The variation in size, as shown by the thinnings, is doubtless 

 caused by the lack of early thinnings. The smaller yield in this plot 

 than in Plot No. 1 is probably caused by the same factor, namely, by 

 heavier stocking and poorer site. The difference in quality of site is, 

 however, very small. 



Sample Plot No. 3, surrounded by an older forest and hence some- 

 what protected, has a clayey loam soil inclined to be somewhat rocky. 

 The humus conditions are good. The author places the quality of 

 the site as midway between that of 1 and 2. This plantation was made 

 in the year 1887, spacing 3 by 4 feet. 



^ The first thinning was made when the stand was 21 years old. 

 No record was kept of the volume removed. The subsequent two 

 thinnings are recorded in the table. 



T.\BLE FOR Plot No. 3 



Before After Before After 



Thinning Thinning Thinning Thinning 



25 Years 28 Years 



Number trees per acre 1,556 1,028 1,028 773 



Basal area, sq. ft. per acre 181.1 142.1 167.5 136.8 



Average diameter, inches 4.6 5.0 5.5 5.7 



Average height, feet 39 . 6 39 . 9 46 46 . 3 



Volume, cu. ft. per acre 3,895 . 7 3,067 . 3 4,186 3,535 . 8 



