THE FORESTS OF ALASKA. 



19 



These logs were cut on Chena River, about 75 miles above Fair- 

 banks, and were above the average in quality. They were cut under 

 a special contract of $5 per thousand extra for long logs, and prob- 

 ably represented the used lengths of the trees. The measurements 

 show an average diameter growth at the butt of 1 inch in eight and 

 seven-tenths years, and an average height growth of 10 inches yearly, 

 which compares favorably with the rate of growth of red spruce in 

 New York and New England. The most rapid diameter growth 

 noted on any of these logs for a period of ten years was 2^ inches, and 

 the slowest growth for the same period 0.4 of an inch. The butts 

 averaged about 2 feet above the ground. The butt swell was avoided 

 in measuring the logs, so that these figures should be safe for use in 

 determining taper and volume. The bark averaged 0.15 to 0.20 of an 

 inch in thickness. 



Ring counts on white spruce stumps on the southerly and easterly 

 slopes on the west side of upper Isabelle Creek, northeast of Fair- 

 banks, are given in Table 3. 



Table 3. — Diameter growth of white spruce as shown by ring counts on stumps, 



with averages. 



Height. 



Diameter 

 outside 

 bark. 



Rings. 



Height. 



Diameter 

 outside 

 bark. 



Rings. 



Height. 



Diameter 



outside 



bark. 



Rings. 



Inches. 

 25 

 22 

 29 

 19 

 24 

 27 



Inches. 

 21.50 

 16.50 

 21.50 

 14.50 

 18.75 

 16.50 



Number. 

 125 

 110 

 120 

 133 

 130 

 130 



Inches. 

 22 

 31 

 35 

 26 

 30 

 28 



Inches. 

 17.00 

 18.00 

 16.00 

 19.25 

 19.50 

 22.50 



Number. 

 125 

 120 

 115 

 120 

 125 

 120 



Inches. 

 34 

 30 

 22 



28 



Inches. 

 17.00 

 17.50 

 15.00 

 24.00 



Number. 

 125 

 120 

 95 

 126 



27 



18.44 121 



These stumps were on a warm, sandy loam soil in a mixed forest 

 of white birch, white spruce, and aspen. They represent the best 

 development of white spruce timber in the Fairbanks region under 

 the most favorable conditions. The average diameter increase was 

 1 inch in 6.6 years. 



About 1 mile north of this place the following counts were made 

 on birch cord wood which had grown under the same conditions as 

 the white spruce. Counts were made on cord wood because it was 

 impossible to distinguish the rings on the birch stumps. 



