PRINCIPLES OF FOREST ECONOMY. 



303 



Market conditions may be snck that the small demand for the first-mentioned class of products 

 would make it unprofitable to cut the growth, and again while, other things being equal, the larger 

 dimensions are not only more valuable and in greater demand, but permit a greater and greater 

 intensity of exploitation, 1 yet the long time during which the capital represented in the standing 

 timber is tied up, and must therefore produce at compound interest, may have a disadvantageous 

 influence upon the balance sheet. 



The determination, therefore, of the length of time during which the growth is to be allowed 

 to accumulate, which is called rotation, requires not only consideration by the teehnicist, but very 

 close and complicated calculations by the manager. According to the point of view from which 

 this period of rotation is determined, we can distinguish and designate these time periods by 

 various names which explain themselves, namely, as silvicultural rotation, lotation of greatest 

 material production, financial rotation of highest harvest value, rotation of highest forest rev- 

 enue, etc. 2 



USTow, if an owner of land should stock it all with forest growth at the same time, he would 

 have to wait twenty, forty, sixty, one hundred years or more, according to the rotation which he 

 has recognized as most desirable, before he would have any returns, or else, if he should have a 

 tract of virgin growth, all ripe tor the ax, and cut it all, he would again have to wait many decades 

 without income until the new growth can be profitably cut. 



Such an intermittent revenue is not only undesirable for private enterprise, but also impracti- 

 cable, since the cost of caring for the property would have to be provided for without any direct 

 income during a long period. 



For small holdings, such as the wood lot of a farmer, attached to the farm and readily super- 

 vised by him while attending to his regular business, the objection to the intermission of revenue 

 is not serious altogether he manages his wood lot mainly for his own use. But in growing wood 

 crops for the market as a business it is necessary to change the intermittent into an annual revenue, 

 or at least one returning in short periods. 



This is done by gradually bringing the forest into such condition that each year, or at least 

 during each short period of the rotation, a portion or parcel, as nearly as possible producing the 

 bame amount of material or revenue, becomes ready for the harvest, until finally the whole forest 

 area assumes the condition of what may be called the normal forest, or at least a regulated forest 



Ideally such a forest when so regulated would yield every year or short period of years the 

 same amount of material and approximately the same money revenue, the amount to be cut 

 annually or periodically being as nearly as possible the amount annually growing. 



If, for instance, we have a pine forest which we propose to manage under a rotation of one 

 hundred years, which means that we expect to return for a new crop within one hundred years to 

 the same acre we have just cut, and finding from our measurements that all our acres are of a 

 uniformly producing capacity, we would have it divided into 100 equally large compartments, each 

 stocked with trees just one year older than the preceding, and successfully representing 100 age 

 classes, so that we could cut each year one compartment with the same amount of wood just one 

 hundred years old. 



1 How, with, the increase m the si/o of the log, the amount of lumber that can he obtained from it increases or 

 the necessary waste decreases disproportionately may be seen from the subjoined table of output, based upon the 

 results of the average sawmill practice: 



. 



Real contents 

 ot log in feet, 

 B M or one 

 twelfth cubic 

 loot allow- 

 ing no waste 



Contents m 



Waste as a 



Diameter ol log (10 fctt lon^)— 



feet B M as 

 per Scribner 



per cent of 

 real contents 





or Boyle's 

 rules 



deduced by 

 Doyle 





65 



2} 



65 





327* 



62 



51 





167 



90 



46 





211 



122 



42 





261 



160 



39 





376 



250 



34 



30 inches.... ». 



588 

 847 



422 



640 



28 

 25 







1,046 



810 



23 





1,635 



1, 322 



20 



2 Note from page 332, Report 1893, "Determining rotation." 



