Forest Mensuration 43 



A number of variations of this method exist, according to the custom 

 of local cruisers and according to the predilections of the lumbermen, 

 largely governed by the value of stumpage. Compare Graves' Bulletin 36, 

 page 1 1 6. 



PARAGRAPH LXVIII. 



DR. FERNOW'S "FORTY" METHOD USED AT AXTON. 



1. Each "forty" is subdivided into 16 squares of 2^2 acres each, the 

 sides of a square being 20 x 20 poles. 



2. The head estimator, stepping from the corner of the square 10 

 poles east (or west) and 10 poles north (or south) places himself in 

 the center of the square. 



3. Helpers (students) are sent out, four in number, towards the north- 

 east, northwest, southeast and southwest, each helper reporting the diam- 

 eter and species of the trees found in that one-quarter of the 2^ acres 

 which is allotted to him. 



4. The "forties" are carefully surveyed and surrounded by carefully 

 trimmed lines. The outlines of the 2j/ acre sections are merely paced. 



CHAPTER II. AGE 



PARAGRAPH LXIX. 



AGE OF TREES CUT DOWN. 



The age of trees cut down is found by counting the annual rings on 

 a cross section (preferably an oblique cut) made as low above the ground 

 as possible. Allowance must be made for the "stump years," by which 

 is understood the number of years required by the top bud of the seed- 

 ling, after sprouting, to reach the stump height ("cutting height," after 

 Circular 445). 



Ring-counting in the case of even-porous hardwoods requires the use 

 of a lens and of some coloring liquid (aniline and ferro-chloride) on a 

 disc planed with a knife, a chisel or a hollow planer. 



The difference of the ring-numbers on the stump and the ring-num- 

 bers at any place higher up indicates the number of years used by the 

 top bud of the tree to traverse the intervening distance. Endogenous 

 trees do not form any rings. 



False rings are formed under the influence of late frost, early frost, 

 drought, fire and insect pests. They do not run all around the tree. 



