32 FOREST commissioner's REPORT. 



AGE OF SPRUCE. 



The first field work performed for the State in the interest of 

 forestry was a determination of the age and size of spruce logs. 

 This seemed worth while on its own account, and it is further prob- 

 able that whenever in the future it shall be attempted to estimate 

 closely the forest resources and growth of the State the results of 

 this work will have a very important use. 



In all. 1050 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 ihe drainage of the Androscoggin. The 

 remainder were partly from the Kennebec, partly from the Aroos- 

 took 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 1,0.50 logs. The averaged dimensions of the 

 logs represent a tree containing about twenty- tliree cubic feet, or 

 say 120 board feet, and this was grown on the average in 192 years. 

 Adding to the log two cubic feet for stump and seven more for the 

 top, adding also to the age twenty more years for the height growth 

 of the stump — then dividing contents by age gives the figure fifteen 

 cubic feet. That is to say, a spruce tree on the average and 

 throughout its life until cut, maintains a growth of one 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 cannot be 

 immediately derived from these figures. 



