304 SUSTAINED XIELD IN CONVERSION ORGANISATIONS. 



generations of men. It is sometimes possible to attain the desired 

 result in a shorter time, but then without that same degree of cer- 

 tainty. To enlist time on one's side in creating the seed-grown foresfe 

 means to have all the natural forces in one's favour ; to run against 

 time is to run counter to them. 



Already we have in France some well-conceived Organis,atioa 

 Projects for the conversion of certain forests, which are in course of 

 execution in a manner that leaves nothing to be desired. Thus, 

 in the Department of the Ardennes, there is the State forest of 

 Slgny-l'Abbaye, which contains 7125 acres. Situated on an ex- 

 cellent forest soil formed of Oxford Clay, in which the silicious ele- 

 ment is considerable, it is stocked chiefly with hornbean, the soft- 

 woods, and birch and oak. Trees of this latter species, rising up as 

 standards above the underwood, attain a diameter of 40 inches in 

 from 150 to 200 years. But, in consequence of the great fertility of 

 the soil, the oak had already begun to disappear from this fine 

 forest, which was then worked as Compound Copse on a Rotation of 

 25 years. Certain prescriptive rights, moreover, prevented Improve- 

 ment Cuttings, that is Cleanings and Thinnings, from being made. 

 The true remedy was a return to the High Forest Regime. Its 

 conversion, ordered by Grovernment, was organised, at the same 

 time that the prescriptive rights referred to were commuted by 

 transferring a portion of the forest in full proprietorship to the 

 persons exercising those rights, and it has been in hand since 1868. 



The forest was found to be naturally divided into 3 regions ; 

 hence three High Forest Working Circles of about 2400 acres each. 

 The Rotation adopted is one of 180 years. This is the space of 

 time judged necessary to obtain from regular high forest growth 

 trees 30 inches in diameter, and it is supposed to represent the pro- 

 bable longevity of canopied crops of oak. The Rotation has been di- 

 vided into 5 Periods of 36 years each, that interval being considered 

 long enough for obtaining the complete regeneration by selfsown 

 seedlings of a whole Block, Each Working Circle is thus divided 

 into .5 Blocks, which will be successively brought under conversion 

 operations in their respective turns. 



The broad lines of work being thus laid down, it was necessary 

 to do nothing but what was certain to yield the desired results. 



