17 



with adjoining portions of Franklin and Middlesex counties. 

 Petersham, where twenty-three sample plots were measured, is 

 the banner town of this region and of the State. 



The growth of individual pine trees, as well as the growth of 

 acre stands has been studied by making what are known to for- 

 esters as stem analyses on more than two hundred and fifty trees. 

 Where cutting is going on, trees are selected and the separate logs 

 are measured for length, diameter and the growth for ten-year 

 periods, as shown by the annual rings. The growth of the vari- 

 ous logs together with the stump and the top when put together 

 make up the growth of the entire tree. The individual trees are 

 then assigned to certain types of growth, and tables constructed 

 which will show the rate of growth of pine under varying condi- 

 tions, and its rate of growth at different ages. 



The yield tables, the growth tables and other information con- 

 cerning the white pine as it grows in this State will soon be pub- 

 lished in bulletin form. 



Yield per Acre from thinning Pure, fully stocked White Pine. 



The above table shows the yield to be obtained by thinning 

 white pine stands of different ages in cases where the stand is 

 pure, containing no other trees but white pine, and fully stocked, 

 that is, without pronounced holes or blanks. 



The table is divided into two parts, one for trees five inches or 

 more in breast-high diameter, the volumes of which are indicated 

 in broad measure. The corresponding money values are given, 

 in the second column the stumpage value at $6 per thousand, and 



