Forest Mensuration 51 



At the stump the rings had best be counted from the inside out, allowing 

 for stump years. Instance: Age of tree, 117; stump years, 4 years; count- 

 ing on the stump, from the inside, 6 rings establishes the ring formed in 

 the year 10. Continuing, the rings of the years 20, 30, 40, 50, etc., up 

 to year no, are pencil marked. The outside seven rings are thrown off. 



At all other disk-sections, count and measure from the outside in, after 

 discarding the 7 years exceeding full decades of tree life. 



PARAGRAPH LXXXII. 

 NOERDLINGER'S PAPER WEIGHT METHOD. 



The total length of the tree is divided into 8 Huber sections, and cuts 

 are made in the midst of these sections, at the height of 1/16, 3/16, 5/16, 

 7/16 and up to 15/16 of the bole. On each cross section the radii are 

 measured, not with the rule, but with dividers. 



On a piece of paper folded 4 times and thus divided into 8 sectors the 

 measurements are entered with the help of the dividers, one sector being 

 allotted to the first cross section, the next sector to the next cross sec- 

 tion, etc. Multiplying the total weight of the zone indicating, say, the 

 year 70, by height of the tree and dividing the product by the weight of 

 a square foot of paper, the volume of the tree when 70 years old is 

 directly obtained in cubic feet. Similarly the zones corresponding with 

 the year 50, 60, etc., are cut out, weighed and multiplied. 



If the volume increment percentage p alone is to be obtained, then it 

 is enough to divide, say, the "weight" of the year 70 by the weight of 

 the year 60, and the loth root of the quotient will equal i.op. 



PARAGRAPH LXXXIII. 

 SCHENCK'S GRAPHIC TREE ANALYSIS. 

 Graphic tree analysis offers the following advantages : 



1. Mistakes are impossible, being at once noticeable on the diagram 

 paper. 



2. The volume in feet Doyle can be readily obtained for any stated 

 minimum diameter. 



3. The graphical sketch is adaptable to any o-f the 43 scales in use in 

 the United States, as well as to the metric system. 



4. The thickness of heart wood and sap wood and bark readily appears. 



5. It is immaterial whether measurements are taken in meters or in 

 feet, the graphical sketch readily allowing of transfers into other units. 



6. Height growth and diameter growth appear at the same time, and 

 from the same entries. 



7. The length of the sections taken need not be uniform. 



The method of proceeding is as follows : On millimeter paper a system 

 of co-ordinates is established; heights are entered as ordinates, diameters 



