GERMAN COMMENT ON FRENCH FORESTRY 483 



this in its practical bearing is expressed in the questions of whether and how high a 

 rate of interest should be expected on the forest capital invested. This question is, 

 indeed, thoroughly discussed in the French Uterature. Its^treatment is of particular 

 interest to the German forest owner, who is occupied with the theory of net income. 

 A very clear discussion of the theoretical and practical problems and objects of the 

 same is given by Tassy, I. c. He lays special emphasis on the nature of forest capital, 

 offers explanations of the differences which exist in the relation of revenue to value of 

 the wood in comparison with other branches of domestic economy, and advances the 

 following propositions: "The rotation period which gives the greatest interest on the 

 investment is almost always shorter than that which corresponds to the greatest mean 

 annual increment. The less valuable the species concerned and the less likelihood there 

 is of its increasing in technical value and in price as it grows older, the earlier does 

 this age occur. The lower the rate of interest the more closely does the rotation yield- 

 ing the greatest interest correspond to the rotation which produces the most valuable 

 product." As opposed to this idea, however, it should be noted that not the greatest, 

 but a suitable interest on the forest working capital is demanded by the German advo- 

 cates of the theory of net returns. 



From these three propositions are drawn defin^e policies for economic management 

 (I. c). Among these it is of special interest to note that by proper thinning the age 

 of maturity is advanced while at the same time the production of the stands is increased, 

 and that the capital, upon which the income is dependent, is diminished by the same. 

 The increasing value of timbers justifies more intensive utilization. The question of 

 underwood and the increased length of rotation are justified by that fact. The in- 

 fluence of the rate of interest is exhibited in the fact that a reduction of it results 

 in a longer financial rotation in such a way, however, that the rotation period corre- 

 sponding to the highest mean value increment, and that corresponding to the greatest 

 net revenue are equal only when the rate of interest is equal to zero. 



In spite of the simphcity and clarity of the arguments whose chief points have been 

 rehearsed, no adequate basis can be derived from the literature cited, for the rotation 

 period which can be considered correct for a given forest region and given species. 

 The examples cited rest mainly upon hypothetical suppositions; they give very in- 

 definite results. The first of these three propositions, namely, that the rotation corre- 

 sponding to the maximum yield culminates just before the culmination of the mean 

 annual increment, allows very wide variation. For the maximum mean annual incre- 

 ment occurs, as has been mentioned under (a) not at any one definite age, but somewhere 

 within a long period comprising or exceeding an entire century. 



More definite inferences as to the rotation period for the French State forests can be 

 drawn from' the actual condition of the forests themselves than from the Uterature. 

 The oak stands under consideration, in the forests of Bellime and Berc6 as well as the 

 stands of fir in the Vosges, can serve as admirable examples from which to deduce more 

 definite economic principles. Both are typical of the kind of stand to which a consistent 

 observance of the principles of the greatest net forest revenue or of the greatest mean 

 value increment will lead; moderate degree of thinning, dense stocking, long rotation 

 period. The volume and value resulting from this system are of a definite amount. 

 Restricted to the revenue at maturity the mean value increment of the stands men- 

 tioned, which consists of 34,255 cubic feet valued at 40 francs ($7.70), amoimts to 

 39,000 -5- 210 = (in round numbers) 180 francs per hectare ($14 per acre) ; this is one 

 of the highest which has hitherto resulted under management anywhere, or been ex- 

 tensively described. The figures given above, however, indicate that, in spite of this, 

 the mean value increment has not yet attained its maximum. Even when the annual 

 volume increment amounts to only 0.5 per cent, and the annual increase in value like- 



