400 Forestry Quarterly 



comprising total estimated stock and increment, an excess of only 

 G per cent in the cut is found over the estimated — a very satis- 

 factory estimating. This is the error in the average on a cut of 

 about 18 million cubic feet. For single stands, to be sure, the 

 differences may be much greater, but from the standpoint of 

 yield regulation for the whole district this does not matter. Since 

 the estimator does not know the sequence of fellings and pro- 

 gress of regeneration, which the manager directs, he cannot for 

 each stand make a prognostication with any tangible amount of 

 accuracy. 



Comparing estimates for different species, the estimates in 

 spruce are most closely covered by the cut, namely only 4.2 

 per cent over the estimate, with very small deficiencies in three 

 revirs, but in single revirs the excess may go up to 14.6 per cent. 



For pine, the total cut showed an excess of 8.5 per cent ; in one 

 revir the excess reached 28.5 per cent, which is, however, sup- 

 posed to be some error. 



In beech, the accuracy of estimate is very much lower than in 

 the conifers, with an excess in the cut of 14 per cent ; and in 

 oak with 14.9 per cent, which in composite forest was stiil fur- 

 ther increased to 15.6 per cent. In the small oak timberwood 

 area, the error was only 6.1 per cent. 



These greater errors in the broadleaf species is to be referred 

 to unsatisfactory form factor and increment determinations. 



Altogether the form factor method has shown itself satisfactory 

 as regards degree of accuracy, which, comparing it in cost, is pos- 

 sessed by no other method. 



Vber Holzmassenschdtzung fiir Zwecke der Waldertragsregelung. Forstwis- 

 senschaftliches Centralblatt, April, 1915, pp. 171-176. 



Neuhaus inveighs against the use of so 



Revolutionary many unknown terms in yield calculations, 



Yield such as normal stock, normal increment, 



Regulation equalization period, rotation. The only 



really tangible, known factor is the actual 



stock. 



As to rotation, he cites Stotzer, that "no rotation can, with 

 assurance, be declared the irrefutably correct one," and Frey, that 

 practically a predetermined rotation is not, cannot, and should 



