FORESTS 



FORESTS 



335 



and ab equals 20; then AB by ab equals 1800; 

 divided by AC, supposed to equal 22, it gives 

 nearly 82 feet as the height of the tree, or DE 

 in the diagram. 



In practice, a gang of four men is frequently 

 engaged in making the survey. A half chain of 

 thirty-three feet is fastened to the belt of the 

 chain-man, vs?ho is guided by a man with a compass 

 in order to make as straight a line as possible 

 through the woods. A man on either side of the 

 chain-man calipers the trees for a lateral distance 

 of thirty-three feet, and calls out the result to the 

 chain-man, who makes record of it on a sheet 

 especially prepared for the purpose. The chain-man 

 also makes note of the direction and size of streams, 

 of hills and of inclines that may be of interest or 

 use in the harvest. The gang proceeds for twenty 

 half chains, when an acre has been covered. The 

 measured acres are tqual distances apart to the 

 right and left of a base line through the tract. 

 Sometimes circular areas of such radii as to contain 

 a certain fraction or a whole acre, considered to be 

 an average of the whole stand, are measured. 



The volume is approximated by multiplying the 

 area of the base of the tree at stump height by 

 one-half the height. Each cubic foot of saw tim- 

 ber will cut out five to seven board feet. About 

 eighty-five cubic feet of wood will pile up a stand- 

 ard cord of 4x4x8 feet, or about thirty solid 

 cubic feet will pile up a cord of sixteen-inch wood. 



As a further means of determining the most prof- 

 itable procedure, stem analyses are made by de- 

 termining the increase through decades by measur- 

 ing the thickness of each ten annual rings, begin- 

 ning at the bark. By deducting from the present 

 volume that at any year previous, the increment 

 during that period is obtained. From the average 

 increment of a sufficiently large number of trees, 

 a reasonably accurate account of what the whole 

 area has been doing can be given and a working 

 plan laid out. This method will determine for the 

 owners whether the area being exploited is large 

 enough to keep the mill running indefinitely. r\ 

 The capacity of mills is usually far too 

 large for the area, so that after a few 

 years' cut a move must be made or 

 the mill go out of the business. ,'*' 



Fellinj. (Figs. 476, 477.) y'^ 



In felling, the tree is y' 

 chipped with the axe ^^'■ 

 on the side in the ,'' 



direction in .,'' 

 which it is ,'' 

 to fall, in 



Q 



^:_,,,H;;:::~ 



13 



order to direct its course. Considerable skill in 

 this matter is often necessary in order to place the 

 tree where it is wanted on the ground. The cross- 

 cut saw is used for the remainder of the cut, 



Fig. 475. 



Diagram showing how to determine height of 

 tree by triangulaticn. 



Fig. 476. FeUing a tree. Drawn from a photograph 

 of a chopper in action. 



beginning on the opposite side from the chipping. 

 When the tree is about to fall the workmen should 

 step off at right angles to the direction the tree is 

 taking, in order to avoid falling limbs that are often 

 thrown in the line with the tree. No attempt 

 should be made to drive farm animals from danger 

 after the tree begins to fall. Failure to heed one 

 or the other of these precautions costs numerous 

 lives every year. Care is taken to avoid breakage 

 as much as possible and to have the logs in a con- 

 venient place for loading. When wood is frozen, it 

 is much more brittle than at other times. When 

 trees are small enough to permit of it, they are 

 cut close to the ground, which makes a saving of 

 timber. In felling the large trees of the West, the 

 choppers stand on a scaffolding. (Fig. 477.) 



Sawmills. (Figs. 478-480.) 



The location of the mill is one of the most im- 

 portant factors in the harvesting of a forest crop. 

 The large mills are always located on a pond, 

 stream or lake, in order to provide water for the 

 steam boilers and to have water into which the 

 logs may be rolled before they are taken into the 

 mill. The logs are taken into the mill by means of a 

 jack-ladder, — a heavy, endless chain that runs in 

 the bottom of a V-shaped groove extending into the 

 water, over which logs are floated, — or other suit- 

 able conveyance. The small portable mill, which is 

 moved about to gather up what the larger mills do 

 not take, is located in a position convenient to most 



