PERIODICAL LITERATURE 



Owing to the irregularity and slimness of forest literature, due to 

 the war, this department must necessarily be meagre for the present. 



The planting of Douglas fir in Denmark wa.^ 



Douglas Fir begun about 1880; since then this species has 



in been planted quite extensively. During the years 



Denmark 190? to 1909 several sample plots were laid out 



in order to obtain more definite growth data. 



Three of such sample plots form the basis for the following discussion 



and comparison by Opperman. The plots used as a basis for the figures 



are rather small, 1/6 to 1/4 of an acre, and of three different degrees 



of stocking and thinning, the age varying from 25 to 30 years, dating 



from the year of germination. The seed used in the Danish plantings 



under discussion here came from the coast of California. 



Plot No. 1, located in a narrow belt of conifers, quite level and 

 quite rocky, the soil being a mixture of coarse sand and clay with a 

 good layer of humus, having been thinned when 18, 20, and 22 years 

 old, showed the following conditions before and after the fourth and 

 fifth thinning: 



Table for Plot No. 1 



Before After Before After 



Thinning Thinning Thinning Thinning 



26 Years 29 Years 



Number trees per acre 844 618 618 457 



Basal area, sq. ft. per acre 187.2 ' 150.5 183.9 148.3 



Average diameter, inches 6.4 6.7 7.4 7.7 



Average height, feet 50.5 51.0 57.4 58.1 



Volume, cu. ft. per acre 4,883.4 3,958.3 5,389.3 4,391.8 



The plantation had been made in the spring of 1885 under an 

 open stand of mature beech. The spacing used was about 3 by 4 feet. 

 About 700 Douglas fir > seedlings were planted on an area of about 

 1/3 of an acre. The sample plot, however, includes only a little over 

 1/4 of an acre, in order that the plot would be entirely surrounded by 

 Douglas firs. The mature stand of beech was removed after a year 

 or two because the Douglas fir could not endure such a dense shade. 



In the first thinning, when the stand was 18 years old, a volume 

 of 563 cubic feet was removed. The next thinning, two years later, 

 removed 674 cubic feet per acre. The third thinning, again after an 

 interval of two years, removed a yield of 413 cubic feet per acre. 



376 



