One system of quick cruising, developed at this Center, was Godman's 

 quick, cruise method—' . It was based on averaging many plots with 

 similar number of trees per acre, average d.b.h., and number of logs. 



A more recent method consists of measuring or estimating diameters by 

 2-inch classes and the number of logs in each tree on a fifth-acre 

 plot and simultaneously accumulating volumes per acre on the plot by 

 using a special circular slide rule. The slide rule, described in 

 Alaska Forest Research Center Technical Note No. 37, was designed for 

 Sitka spruce and western hemlock of form class 82 and western redcedar 

 of form class 75. Other form classes can be used. 



Site Index Determination in Even-aged 

 Sapling and Pole Stands 



Site index determined by the usual method of height-age relationships 

 is unreliable in stands less than 30 years old in Southeast Alaska. 

 Consequently, estimates of site productivity and future yield cannot 

 be made by this method in young stands. 



A method for using internodal span for determining site index in 

 juvenile Douglas-fir stands was suggested by Wyliel.' and developed by 

 Warrack and Fraser— '. The applicability of the procedure in this 

 region is being studied using internodal span of Sitka spruce. 



The lengths of 6-node spans, beginning with the first node above breast 

 height, were measured in young-growth over 30 years old and compared 

 with site index determined by the height-age method. The indications 

 are that a fairly consistent site index determination can be obtained 

 by reference to internodal span. Initial results show that site index 

 can be determined to within 20 feet of the height-age method 83 percent 

 of the time. The tabulation below shows the range of differences in 

 site index determined by 6-node span as compared with the conventional 

 height-age method on 23 plots. 



6/ Godman, R. M. A site classification and "quick cruise" volume 

 table for climax stands. Alaska Forest Research Center, Tech. Note 

 No. 11, 3 pp. , 1951. 



l_l Wylie, N. A. Determining site index in young Douglas-fir stands. 

 Thesis submitted in partial fulfillment for requirements of British 

 Columbia Registered Foresters' Association. (Cited by Warrack and 

 Fraser, below.) 



8/ Warrack, Y. C. and A. R. Fraser. Estimation of site quality in 

 juvenile Douglas-fir stands. British Columbia Forest Service, Research 

 Note 28, 5 pp., 1955. 



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