14 FOREST commissioner's report. 



One section of the tree schedule has not yet been referred to. That is 

 the detail of sections. The tree under discussion was cut oft at 5 points 

 between 10 and 11 feet apart, one kerf of each cut being squared. The 

 diameter of this was measured inside the bark, a pencil line drawn from 

 the heart to the bark at some point where it equalled the average radius 

 of the section, and then the rings of yearly growth were counted, begin- 

 ning with the bark and marking every tenth one. Finally the breadth 

 of these groups of rings is measured, or wliat amounts to the same thing, 

 the distance of each mark made from the bark end of the line. 



Thus turn to section 1 in tlie schedule. It was put in at 16 feet from 

 the ground, and the diameter of the wood at that height was found to be 

 7.8 inches. An average radius then is 3.9 inches and this was drawn on 

 the kei-f in pencil. Count of the yearly rings along this line show? there 

 are 77 of them. The outer 10 rings are togetlier only .2 inches thick, the 

 next 10 rings are of the same thickness, and so with the third group. 

 Inside that, the rings are thicker. Similarly with the second and higher 

 sections. Those who are willing to give the matter a little close attention 

 will find themselves amply repaid for carefuUj' comparing these measure- 

 ments. This tree I may saj' seems to be for its conditions a very typical 

 and regular one. 



Now since we know from the caliper measures and the measured thick- 

 ness of bark what the true wood volume of the tree is, since, as just noted, 

 we know also how thick a la3^er at ditlerent heights in the tree the wood 

 grown in the last 10 years amounts to, we have, it will be seen, the means 

 of calculating how much wood has grown in the last 10 years, or, what 

 amounts to the same thing, how big the tree was 10 years Mgo. The 

 process of calculation I need not explain. A man who knows enough 

 mathematics to figure out the problem if told how will be able to plan 

 his own solution. I will refer, however, to pages 85-92 of the last Maine 

 report and the diagrams there given as perhaps throwing light on the 

 whole subject. 



And if 10 years back, then 20, 30 and 40. The diameter of the tree at 

 any age at different heights, and consequently data for determining its 

 volume, are all contained in these measurements. The more sections 

 there are, the more accurate will the results be. 



Let me now give a little table showing as the result of calculation the 

 history of this tree's growth. All volumes include bark. Under 50 years 

 of age it must be said we have not sufficient data for calculating the vol- 

 ume of the tree. This part of the table was put in largely by guess. 



