Periodical Literature 559 



Finally, W'appes urges the closest cooperation of individual 

 investigators with the experiment station and the unfailing en- 

 couragement of the higher administrative officers, if good results 

 are to follow. Such projects as the measurement of mixed stands 

 must be decentralized, since the exact knowledge of local condi- 

 tions is of paramount importance both in getting the field data 

 and in working them up. A. B. R. 



Ueber Technik und Methode der Aufnahme von Mischbestanden. Allgemeine 

 Forst- und Jagd-Zeitung, February, March and April, 1915, pp. 33-39, 57-67, 

 81-89. 



On 43 pages Professor Dr. Schiipfer 

 Increment elaborates in great detail and somewhat 



Measurements critically the various methods of ascertain- 

 ing increment on single trees and stands. 

 There is little or perhaps nothing new in the article, but it is 

 a clear, complete exhibit of this chapter of forest mensuration 

 by an expert, the comparisons of results by various formulae 

 being sometimes in the nature of new material. 



A brief historical note to efforts at increment measuring in 

 the eighteenth century introduces the subject. The writer perti- 

 nently points out that in all forest measurements only approxima- 

 tions can be secured, yet the degree of accuracy should as far as 

 possible be realized. In the section of increment determination 

 on single trees, the method on felled trees is taken up first, and 

 the difference in results of the precise and the approximation 

 formulae is exhibited. 



The author points out that, if on every range even a modest 

 number of measurements were made with precise record of age, 

 site, length of shaft, crown and tree class, whether dominant, 

 etc., in a short time considerable knowledge could be cheaply 

 accumulated, and at the same time young foresters educated. 



In the section relating to standing trees, it is shown that the 

 condition of height growth and form change having ceased is 

 probably much rarer than believed. The author found 150-year- 

 old pines still growing at the rate of 2 inches, and 210-year-old 

 ones between 1 and 2 inches, while Hartig found oaks at 240 

 years still making up to 2-inch height growth, and even these 

 small amounts influence the increment per cents. Tabulations are 

 given of actual measurements comparing area-, volume-, form- 



