334 



FORESTS 



FORESTS 



Fig. 473. Stand of pine ready for harvest. 



the same time have much in common. A discus- 

 sion of the practices employed in harvesting tim- 

 ber on a large scale will be suggestive to the 

 thoughtful reader, and will enable him better to 

 direct his efforts in a small way; and the few 

 points regarding the harvesting of the farm wood- 

 lot that need especially to be noticed will be more 

 easily comprehended. 



Methods of harvesting. 



There are two distinct methods of harvesting 

 forest crops practiced in the United States, — clean 

 cutting and selection cutting. Each has its ad- 

 vantages and advocates. 



Clean cutting has been practiced more exten- 

 sively in the past, and it is still in vogue where 

 timber is plentiful. It has the advantage of free- 

 dom of action, little or no attention being given 

 to saving young trees for future crops ; the ground 

 is gone over but once to secure the marketable ma- 

 terial ; and economy of logging and milling opera- 

 tions is eifected. Clean cutting is the most prac- 

 tical method where the trees are even-aged or are 

 of nearly the same size, all having reached a stage 

 when growth is slow or has nearly ceased, and 

 practically all are ready for the harvest. This is 

 frequently the best method in coniferous forests, 

 where there is often but little undergrowth. Some 

 lumbermen who have had wide experience in cut- 

 ting hard-woods, including broad-leaf trees, in- 

 sist that this is the most practical method even 

 under those conditions. In the case of clear plant- 

 ings that have reached the proper stage, clean 



cutting is used for final harvest, thinnings 

 having been removed from time to time. 



When this method is to be employed, in 

 order to know approximately the quantity 

 of timber, it is customary to engage a 

 timber - cruiser, who passes through the 

 timber along more or less definite lines 

 making careful observation to the right 

 and left, estimating the quantity of tim- 

 ber of each kind as he passes. Record is 

 made of the estimate of each part of a 

 section, and at the end the estimates are 

 summarized. It requires a man of much 

 experience in-a particular kind of timber 

 to be of any value as a cruiser. A man 

 habituated to the timber in the lake or 

 gulf states would be at a loss among the 

 redwoods and sugar pines of the West. 



Selection cutting consists in removing 

 the more mature trees of a given species 

 or of all species down to a certain diame- 

 ter limit. On large tracts a valuation sur- 

 vey is made at the time to determine the 

 quantity of timber in board feet above a 

 certain diameter limit. In measuring the 

 diameter it is always taken at breast- 

 height (Fig. 474), or four feet and four 

 inches from the ground, to avoid the usual 

 expansion at the base. The diameter limit 

 is any that may be determined on, but is 

 usually twelve, fourteen or sixteen inches ; 

 the lower the limit the greater the harvest 

 at the time and the longer the period that must 

 elapse before another equal harvest can be gath- 

 ered from the same land. Usually 2 to 6 per cent 

 of the timber is measured, and from this the re- 

 mainder is estimated. If the tract is small, a 

 higher percentage or even all the trees may be 

 measured. As this 

 method implies 

 making calcula- 

 tions for another 

 crop, the diameter 

 of all species down 

 to two inches is 

 frequently taken. 

 Calipers are used 

 for measuring the 

 diameter and a 

 hypsometer for 

 determining the 

 height, although 

 the height may be 

 ocularly estimated 

 for all practical 

 purposes in that 

 particular kind of 

 timber. If a hyp- 

 someter is not at 

 hand, the height 

 of a tree or any 

 point on it may be determined by triangulation, 

 according to the following diagram (Pig. 475): 



^0 " = DEi or, in figures, suppose AB equals 90, 



Fig. 474. Measuring witli calipers. 



