732 JOURNAL OF FORESTRY 



Hanzlik's^ table for the growth of lodgepole pine indicates an aver- 

 age annual growth in diameter of 4.5 mm. for the years from the 

 twentieth to the twenty-fifth and 5 mm. from the twenty-fifth to the 

 thirty-fifth. The forest on which his investigations were made is in 

 east central Oregon. 



A table for Douglas fir given by Munger* shows an average annual 

 increase in diameter of 0.43 inch from the tenth to the twentieth year 

 and 0.38 inch for the following decade. This is an annual average of 

 10.12 mm. for the twenty years. His table is based on 1,807 stump 

 analyses. His data were obtained from a number of typical localities 

 all west of the Cascade Mountains and east of the Coast Range from 

 the Canadian line in Washington to Cottage Grove, Oregon, on the 

 better class of soils. He calls attention to the fact that the most rapid 

 growth is made where the soil is deep, loamy, fresh, and well drained, 

 where the growing season is long and the stand fully stocked but not 

 overcrowded. He says : "It is not unusual for trees from ten to thirty 

 years old to add 4 feet to their height and three-fourths of an inch to 

 their diameter in one year." 



The West Coast Lumberman® gives data on the growth of the Doug- 

 las fir which indicates an average growth of 8.75 mm. in diameter for 

 the years from the twentieth to the thirtieth. 



Many of the measurements made on Douglas fir by the writer were 

 on the stony soils near Silverdale, Wash. 



Annual Growth of Conifers in Diameter Outside of Bogs 



Writer's data Data of other workers Ratio 

 mm. mm. 



Western hemlock 1.56 3.6 2.2 



Western white pine 1.34 4.68 3.5 



Lodgepole pine 1.59 4.8 3.0 



Douglas fir 1.69 9.43 5.5 



The above table summarizes the foregoing results and compares 

 them with those of the writer. It is seen that all of the forest workers 

 have found these conifers growing much more rapidly than the writer 

 has, the ratio for the different species varying from 2.3 to 5.5. The 

 difference in the character of the soil, the amount of moisture in soil 

 and in air, and the age of the trees are doubtless among the most im- 

 portant factors in these differences. The comparison merely empha- 



'^ Hanzlik, E. J. : "A growth and volume study of lodgepole pine in the Ochoco 

 Mountains." Forest Club Annual, Univ. of Wash., 4:27-33, 1916. 



* Munger, T. T. : "The growth and management of the Douglas fir in the Pacific 

 Northwest." U. S. Forest Circular 175, 191 1. 



" "Douglas fir." The West Coast Lumberman, Dec. 15, 1913, p. 35. 



