Periodical Literature. Ji 



average increment as avowedly the basis for determining the 

 rotations after the example of Hartig. But the data for such de- 

 termination seem scanty. A determination of the average incre- 

 ment of one of these 200 year old stands brought out 96 cubic 

 feet, and counting in probably unbooked thinnings, 100 cubic 

 feet may be assumed. The current increment was by a casual 

 increment per cent, calculation found to be at about the same 

 amount, so that here really the 200 year rotation seems to repre- 

 sent that of the highest average increment. In the latest German 

 yield tables of Schwappach, this rotation lies on best sites at 

 100 years. It was, however, found that under the French con- 

 ditions both current and average increment remain nearly alike 

 for a century or more, so that the greatest uncertainty arises as 

 to the proper felling age determined from this point of view of 

 volume production. 



The French Forest Administration admits the obligation of de- 

 voting its forests to growing stout sizes, hence value increment 

 enters if not in calculation, yet in general judgment the question 

 of ripeness. Stem classes formed by circumference measure- 

 ments (200, 100-200, under 100 cm.) which, translated, cor- 

 respond to 26, 13 to 26, under 13 inch diameters bring (the trees 

 are sold on the stump) $13, $9 and $6 respectively. While these 

 data are insufficient for an accurate value increment calculation, 

 in connection with the diameter increment calculations they allow 

 an estimate of at least 1 per cent, annual value increment. Other 

 calculations show that from the standpoint of value increment the 

 stands should still be left growing. 



As regards the justification of the rotation upon the basis of a 

 proper interest earning on the wood capital, while this is dis- 

 cussed in French literature, nothing tangible appears in the 

 regulation work, but general considerations lead to the belief that 

 such long rotations do not pay, and by proper thinning practice 

 the same dimensions and values can be grown in much shorter 

 time. 



The French have thoroughly recognized the fact that timber 

 growing is not a business for the private individual. Tassy says : 

 "It is not to be hoped that private owners will ever find their 

 interest in the management of their woods in the form of timber 

 forest. To lead them to this, it would be necessary not only for 

 money interest rates to sink considerably but, what is more dif- 



