Periodical Literature. 275 



Such studies as these of the Swiss Experiment Station deserve 

 to be read widely. A. B. R. 



Mittcilungcn der Schwcizcrischcn Zentralanstalt fiir das forstliche 

 Versuchswesen. Vol. X, No. 3, 1913, Zurich. Allgemeine Forst- und Jagd- 

 Zeitung, January, 1914, pp. 18-24. 



Wimmenauer, with characteristic mod- 



Volume Production esty, contributes some interesting data on 



of this question. In mixed stands of beech 



Pure and Mixed and oak in Hesse, where the beech oc- 



Stands. cupied from 88 to 35% of the total basal 



area of the stems and the oak from 12 to 



65%, investigation showed that such mixed stands yield more 



volume than pure stands, when the proportion of oak is 20% 



and over. 



In mixed stands of beech and Scotch pine in the Odenwald, 

 where the beech occupied from 63 to 15% of the total basal area 

 of the stems and the pine from 2)7 to 85%, investigation showed 

 that such mixed stands yield more volume than pure stands by 

 19% and may run as high as 34% and 37% greater volume. This 

 advantage in volume accrues when the proportion of pine is 50% 

 and over. A. B. R. 



Zur Fragc der Mischehcstandc. Allgemeine Forst- und Jagd- Zeitung, 

 March, 1914, pp. 90-93 (see also p. 109). 



Forstmeister von Gabnay brings together 

 Damage the latest information regarding the in- 



by fiuence of asphalt or other tar coverings on 



Tar. trees. He first points out that the tarring 



of trees against insects produces the death 

 of the cambium layer and, if the bark has been removed near 

 to the wood, of several layers of sap wood, which may after- 

 ward be overgrown, but leave a defect that can never be cured. 

 A number of Frenchmen were first in the field investigating 

 the influence of asphalting roads, but the most extensive investi- 

 gation is that of Professor P. Claussen, who reports in the Pro- 

 ceedings of the Imperial Biological Institute for Agriculture and 

 Forestry (Vienna). These investigations show that there is a 

 great deal of diflFerence in the tar used, some of the manufactures 

 being poisonous and others not. The vapors arising from as- 

 phalting during the operation are fotmd to be damaging the foli- 



