304 Forestry Quarterly. 



Oder, the site classes change from I to V as lower and lower 

 levels are reached ; again proceeding in another direction the 

 opposite series is found, i. e., from higher to lower levels the site 

 improves, except that small heads above the highest plateau 

 belong to site V. The explanation is found in the fact that in 

 the first area the groundwater lies so deep that it has no effect 

 on the surface cover, while in the second area the groundwater 

 is the determining factor and the levels to which it is most acces- 

 sible are the better sites. 



The chemical analysis of the soil in the first series shows an 

 unmistakable relation between the mineral constituents and the 

 yield or site class. At the same time in mechanical composition 

 the variation is still more marked and establishes closest connec- 

 tion between yield and soil contents of clay or silt particles. It 

 should be stated that this area is located in a rain-poor district, 

 and, as it depends on the rainfall, the groundwater not being 

 available, the water capacity of the soil due to larger or smaller 

 amounts of silt particles becomes most important. In the second 

 area, which according to both chemical and mechanical analysis 

 should be ranged into the lowest site classes, the access to ground- 

 water compensates for these unfavorable conditions and pro- 

 duces stands of class I and II. Under such conditions almost 

 pure quartz soils can still be good forest soils. 



Reference is also made to the influence of humus and it is 

 pointed out that the greater humus content of the better sites is 

 due to greater foliage and litter production. On the sites of class 

 V an increase of humus through the stand or natural flora can 

 hardly be expected. Yet, by underplanting of species producing 

 more litter than the pine, even such soils could be stimulated to 

 greater production, for in this way as by addition to silt particles 

 the physical condition of the soil would be improved, notwith- 

 standing deficiency in minerals. (See following article.) 



As regards the use of mineral fertilizer the author explains that 

 many a failure in results may be explained by lack of water. It 

 is therefore more important to increase the water capacity of the 

 soil by careful preservation and increase of humus content, avoid- 

 ing severe opening, removing weed growth and by superficial soil 

 culture. 



Brtragsleisfunn und Bodenheschaffenheit bei der Kiefer. Zeitschrift 

 fiir Forst- und Jagdzeitung. Nov., 1910. Pp. 649-656. 



