450 forestry Quarterly. 



gard to the present stocking of Douglas fir stands in western 

 Washington and Oregon: — 



1. The immature stands contain from 25-50% too many stems. 

 Heavy thinnings are necessary for increased increment and will 

 give a fairly good money return, at the same time benefiting the 

 stand silviculturally. Stands on the better quality soils require 

 very little thinning after 70 to 100 years of age. 



2. Mature stands of the better qualities are probably very little 

 overstocked ; on the poorer qualities the stocking is too heavy 

 due to an excessive number of trees under 12 inches D. B. H., 

 which no doubt retards the growth of the larger trees. 



3. In even-aged mature stands (over 100 years of age) of the 

 first quality a stocking of about 100 trees per acre at maturity will 

 produce the greatest yield in board measure as practically all 

 the trees in the stand are of a merchantable size (12 inches or 

 more in D. B. H.). 



6. Comparison', of Yield on Bench and Bottom Land. The con- 

 clusion is reached that land which is considered as first class agri- 

 cultural soil will not always yield as large a forest crop as land 

 which is classed as inferior for agricultural crops. Mr. Hanzlik 

 also shows that Douglas fir makes its best growth on a slope 

 rather than on level land and that one of its requirements is that 

 the land be well drained. 



7. Methods of Determining Site Qualities of Douglas Fir 

 Stands. Mr. Hanzlik compares the four chief methods of de- 

 termining site quality: i) by optical inspection. 2) by the use of 

 the height growth of the dominant trees, 3) by the growth of the 

 stand in cubic volume, 4) by the density factor (based upon the 

 assumption that the height, basal area and the age of a stand are 

 related by a constant factor). Except for some slight discrep- 

 ancies, this factor agrees with the site quality as determined by 

 the growth of the stand in cubic volume. The factors are be- 

 tween 200 and 500; for division between Quality I and Quality 

 n 400 is an appropriate number, while 300 separates the second 

 quality from the third (on scale of five qualities H-HI and HI-V). 



Dr. Adam Schwappach has briefed Mr. Hanzlik's report in 

 the October, 1913, number of the Zeitschrift fiir Forst-und Jagd- 



