Periodical Literature. 481 



and surface layers of soil of higher water capacity prevent pene- 

 tration. On the other hand, the naked soil can derive use of the 

 lightest precipitation and thus in the very most dangerous sea- 

 son supplies moisture to the roots. On this area the drying 

 out, but also the watering is most intensive, hence in very dry 

 years, the moss cover is a disadvantage, the interception being 

 more dangerous than the prevention of evaporation effective. 



Hence, as briefed before, the raked area had in the dry year 

 1904 shown less loss in increment than the unraked. Yet the 

 damage of moss cover in dry years appears much greater than 

 its advantage in wet years. 



Vergleichende Bodenfenchtigkeitsbestimmungen, etc. Centralblatt f. d. 

 g. Forstwesen, May, 191 1, pp. 187-269. 



The large and growing area of bog land 

 Cause in northern Sweden seriously lowers the 



of productivity of the forests in that region. 



Bog Formation. It is according to H^sselmann, not the 

 water which prevents vigorous forest 

 growth on these bogs, but the fact that the bog-water carries 

 very little or no oxygen in solution. What oxygen is absorbed 

 from the air is fixed by the humus the water contains. It has 

 been shown that humus, especially when wet, absorbs oxygen 

 very rapidly; also that trees grow well in those bogs where con- 

 ditions permit a normal amount of oxygen in the water. Re- 

 moval of the water by drainage is being undertaken to remedy 

 this condition. 



Ueber den Sauerstoffgchalt dcs Bodenzvassers und dessen Einwirkung 

 auf die Versumpfung dcs Bodens und das Wachstum des Waldes. Silva 

 IV. Pp. 65-6. (March, 1911.) 



SILVICULTURE, PROTECTION AND EXTENSION. 



As a result of an inspection visit of a 



Selection number of prominent forest managers to 



Strip Gaildorf, the district in which Wagner de- 



Method. veloped his now well known method of 



regeneration a somewhat detailed report of 



their findings is given by Miiller. 



The main object of Wagner's method is to obviate large felling 

 areas and progress as far as possible by use of natural regener- 



