THE RED SPRUCE. 



39 



136 * board feet. A 16. 25-inch tree similarly is 66 feet tail and has a 

 volume (interpolated) of 188 board feet. Thus the increased growth 

 during the 15 years is 52 board feet, equivalent to 38 per cent. 

 When the future yield of whole stands is to be computed a tabular 

 arrangement of such values will be found convenient. 2 



Inch 



diameter 



class. 



1 



Corre- 

 sponding 

 height. 



2 



Corresponding 

 volume. 



Diameter. 



Corresponding volume value 

 from (4). 1 



Direct 



from 



volume 



table. 



3 



Values 



in (3) 



curved. 



4 



10 years 

 hence. 



5 



20 years 

 hence. 



6 



30 years 

 hence. 



7 



10 years 

 hence. 



8 



20 years 

 hence. 



9 



30 years 

 hence. 



10 



8 

 9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18 



Feet. 

 47 

 50 

 53 

 56 

 58 

 60 

 62 

 64 

 66 

 68 

 70 

 71 

 73 



Board ft. 



34 



43 



55 



82 



97 



120 



130 



150 



200 



230 



2C0 



290 



320 



Board ft. 



31 



43 



58 



75 



95 



118 



143 



170 



200 



230 



2C0 



295 



Inches. 

 10.2 

 11.2 

 12.1 

 13.0 

 13.8 

 14.7 

 15.5 

 16.3 

 17.1 

 17.9 



Inches. 

 12.5 

 13.4 

 14.2 

 14.9 

 15.7 

 16.4 

 17.0 

 17.6 

 18.2 

 18.9 



Inches. 

 14.7 

 15.6 

 16.3 

 16.9 

 17.5 

 18.0 

 18.5 

 18.8 

 19.3 

 19.8 



Board ft. 



61 



77 



97 



118 



138 



162 



185 



209 



233 



257 



Board ft. 

 107 

 128 

 148 

 167 

 191 

 212 

 230 

 218 

 267 

 291 



Board ft. 

 162 

 188 

 209 

 227 

 245 

 260 

 278 

 288 

 306 

 324 



19 















20 



331 





























1 Interpolated, 



It will be noted that in column 3 the values have not been interpolated, although they might well have 

 been. Instead they have been read directly from the volume table and the irregularities evened off in 

 column 4 by curving. The values in columns 8, 9, and 10 are interpolated from column 4 in order to eliminate 

 the irregularity that would otherwise result from rounding off the diameter values in columns 5, 6, and 7 

 and reading direct from column 4. Curving of the values in 8, 9, and 10 may in some instances be necessary. 



The figures contained in Tables 15 and 16 show the comparative 

 development of spruce in the Adirondacks and West Virginia under 

 "average maximum" growth conditions. Unfortunately, the data 

 were insufficient upon which to extend the New York table above 120 

 years. An inspection of the height and diameter tables upon which 

 this is based, however, shows the growth of each very much slack- 

 ened. Inspection of Table 15 itself shows that the periodic annual 

 growth cuhninated in the ninetieth year, while the mean annual 

 would unquestionably culminate under 150 years. In West Virginia, 

 on the other hand, the periodic annual growth does not begin to 

 slacken until the one hundred and fiftieth year, while the mean annual 

 growth continues unabated until the two hundred and fiftieth year. 



i Under ordinary circumstances it would be sufficiently accurate to use the value corresponding to a 

 14-inch tree 60 feet in height which, according to Table 29, is 130 board feet. In computations of this sort 

 however, the volume table values had better be interpolated so as to secure a closer reading. Thus, it 

 may be assumed that if a 14-inch tree has a volume of 130 board feet when 60 feet tall and 160 board fe?t 

 when 70 feet tall, when it is 62 feet tall its volume will be 136 board feet (130 (160-130) by 0.2). 



2 The tabular form indicates all the steps to be taken in making up such a table of values for red spruce in 

 New York under "average maximum" growth conditions. 



