XATITRAI, ROTATION 117 



apt to break down fast, and leave the field practically free for young 

 growth which now gets plenty of light to start. This new stand is 

 practically even aged, trees develop and grow old together and the 

 story of decline and replacement by a new stand repeats itself. With 

 these species the pure even age stand is rather rule than exception in 

 our wild woods. 



In mixed stands of hardwoods the case is entirely different: 

 Normally the site (soil, etc.) is much better; the several species 

 differ in tolerance, growth, reproduction and they vary in longevity 

 and resistance to injury. . Here the stand does not go down together 

 (unless it is a case of windfall), is constantly reproducing, every 

 opening is filled, it rarely forms even aged stands over large areas 

 and even when it does (after accidental destruction) reproduction 

 sets in long before the old stand really breaks. We have the Selec- 

 tion Method practiced by nature. It is reasonable to assume that on 

 any one township of hardwoods in the Ohio Valley in virgin state 

 the total amount of timber remained fairly constant; growth and 

 decay balanced, old, middle aged and young stuff, i. e., the Age 

 Classes were properly represented ; rotation varied for different 

 species, but it was always the average life of the species. In this 

 way these virgin, mixed woods presented a certain regularity com- 

 parable to that attempted by the forester. On the other hand, a 

 property stocked with pure stands of even aged pine, etc., may or 

 may not be regular. In fact there are areas of Lodge Pole Pine of 

 over 100,000 acres in which certain age classes are almost wanting, 

 a fact which needs consideration in planning for a steady supply of 

 timber and income. 



g. Choice of Rotation in United States. 



Generally, Rotation should be chosen no longer than is neces- 

 sary to produce desired material, a good income from the land, with 

 full assurance that the fertility of the land is not impaired. 



On good sites, with good growth and high stumpage calculation 

 of net rental on a reasonable interest rate should never be omitted. 

 In such calculation the? following facts should have due con- 

 sideration : 



i. Sizes demanded by the Market are growing smaller, but will 

 probably not go beyond present European limits. 



