PERIODICAL LITERATURE 377 



Th& next thinnings were made four and seven years later, with the 

 above resnits. 



The total yield, then, on the basis of the plot, at 29 years of age, 

 is 7,964.3 cubic feet per acre, of which 2,575 cubic feet consists of 

 thinnings. The intermediate yield at this early age was thus 32.5 per 

 cent of the total yield. The mean annual growth was, altogether, 274 

 cubic feet per acre, while the current annual growth for the three-year 

 period is 477 cubic feet per acre. The culmination of either yield has 

 probably not been reached as yet. It is interesting to note that, in 

 the thinning at 26 years of age, the removal of 26.7 per cent of the 

 number of trees removed 18.9 per cent of the volume. The removal 

 of these trees increased the average diameter .3 of an inch and the 

 average height .5 of a foot. The thinning made three years later 

 removed 26 per cent of the number of trees and 18.6 per cent of the 

 volume. In this case the thinning raised the average diameter .3 of 

 an inch and the average height .7 of a foot. In the three years after 

 the fourth thinning the basal area increased over 22 per cent and 

 the volume 36 per cent. 



It is interesting to note the uniformity of the stand, as shown by 

 these figures, for the two thinnings. This intensive system of thinnings 

 is very typical of Danish methods and is of wide interest because of 

 its intensiveness. 



Plot No. 2 was located in northeastern Sjaelland, with continental 

 climate. The plantation in which the plot is located is surrounded 

 by young stands of fir (Abies) and beech. The plot, consisting of a 

 little more than ^ acre, has a slight southwest exposure. The soil 

 is a moderately coarse sand, which gradually grades into a fine sand 

 sub-soil, with a considerable layer of humus; the site being classed as 

 slightly inferior to that of Plot No. 1. 



The plantation was made in the year 1885. It consisted of 1,500 

 Douglas fir seedlings spaced about 4 by 2^ feet. In the year 1890, there 

 was an attack by the root fungus Polyporus radiciperda which caused 

 quite a loss. The resulting fail places were filled with larch and spruce, 

 but practically all these were killed through suppression. 



The first thinning was made when the stand was about 26 years 

 old, when about 1,200 trees per acre were removed, with a volume of 

 about 1,271 cubic feet. This thinning, however, was more of an 

 improvement cutting than a thinning. The first real thinnings gave 

 the following data: 



