THE BED SPRUCE. 



33 



Table 8.' — Diameter and age of spruce in Maine. 1 

 [(o) Averaged according to age] 



Class. 



Number 

 of trees. 



Per cent 

 of total 

 number. 



Average 

 age. 



Average 

 butt di- 

 ameter. 



Average 

 length. 



Average 

 top di- 

 ameter. 



Tiider 125 years 



125-150 years 



150-175 years 



175-200 years 



200-225 years 



225-250 years 



250-275 years 



275-300 years 



Over 300 



Average of all 



52 

 120 

 210 

 218 

 210 

 125 

 72 

 29 

 14 



4.9 



11.4 



20.0 



20.8 



20.0 



11.9 



6.9 



2.8 



1.3 



114.5 

 138.7 

 162.6 

 182.6 

 210.8 

 235.5 

 260.3 

 285.6 

 311.6 



Inches. 

 11.5 

 12.1 

 12.9 

 13.5 

 15.0 

 15.9 

 16.0 

 17.5 

 18.5 



Feet. 

 26.4 

 28.5 

 29.9 

 30.3 

 31.3 

 32.2 

 32.9 

 34.4 

 37.1 



Inches. 

 8.0 

 8.5 

 8.6 

 8.9 

 9.9 

 10.0 

 10.3 

 11.5 

 12.0 



1,050 



192.0 



14.1 



30.6 



9.2 



[(6) Averaged according to butt diameter.] 



Class. 



Number 

 of trees. 



Per cent 

 of total 

 number. 



Average 

 age. 





42 



97 



123 



158 



162 



117 



94 



76 



62 



43 



19 



57 



4.0 



9.2 



11.7 



15.1 



15.3 



11.2 



9.0 



7.3 



5.9 



4.1 



1.8 



5.4 



162.0 





170.1 





171.7 





174.0 





3 189. 1 





3 185.4 





197.7 





214.0 





217.1 





228.7 





230.1 





244.8 









1,050 













i From a special report " On the Growth of Spruce, by Austin Cary, in the Second Annual Report of the 

 Forest Commissioner of the State of Maine, 1894. In explanation of the foregoing table Mr. Cary says: 

 "In all, 1,050 spruce logs were examined for this purpose, taken on drives and mill yards. The length and 

 end diameters of each log were measured, and the rings of the butt counted to ascertain the age. About 

 two-thirds of the logs were grown in the western part of the State on the drainage of the Androscoggin. The 

 remainder were partly from the Kennebec, partly from the Aroostock branches of the Penobscot. A small 

 proportion of the logs measured were cut for pulp, which renders the selection all the more representative. 

 The tables which embody the results of the work need, it would seem, very little explanation. The trees 

 were first divided into age classes, and the dimensions of the logs in each class averaged. Then the same 

 logs were divided according to butt diameters and the average age ascertained for trees of each size. The 

 most usable result of the work is the grand average of these facts for the whole 1,050 logs. The average 

 dimensions of the logs represent a tree containing about 23 cubic feet, or say 120 board feet, and this was 

 grown on the average in 192 years. Adding to the log 2 cubic feet for stump and 7 more for the top, adding 

 also to the age 20 more years for the height growth of the stump, then dividing contents by age gives the 

 figures fifteen-hundredths cubic feet. That is to say, a spruce tree on the average and throughout its life 

 until cut, maintains a growth of 1 cubic foot in six and two-thirds years. In adult life the growth per tree 

 would be considerably greater. In young seedlings it would for many years be less. The percentage of 

 growth to stand can not be immediately derived from these figures." 



[In connection with the information just quoted.it seems evident that the words "log" and "tree" are 

 used synonymously in referring to the "used length." — Author.] 



2 A log of these average dimensions contains 23 cubic feet, or about 120 board feet. 



3 A 13i-inch tree, of course, is not as a rule older than a 14Hnch tree. The irregularity shown in the series 

 would doubtless be corrected if the larger number of trees was taken, 



Average of 50 pine logs: Age, 102.8; butt diameter, 16.1; length, 30.3; top diameter, 11. A log of these 

 dimensions contains 30 cubic feet, or about 175 board feet. 



It is in most cases of little practical value to the lumberman to 

 know the direct relation between the actual age and the diameter of 

 trees in a selection forest. A knowledge of the length of time required 

 for a tree to grow from 1 inch diameter class to the next is, however, 

 important. Tables 9, 10, and 11 show this as well as the corre- 

 sponding rate of growth per annum of each diameter class. 1 



1 Besides showing these values based on an average of all trees measured, the West Virginia and Adiron- 

 dack tables show absolute maximum and average maximum values as well. These are obtained by using 

 only values representing maximum and average minimum growth conditions, eliminating all periods which 

 show the effect of suppression. 



84949°— Bull. 544—17 3 



