192 MINNESOTA BOTANICAL STUDIES 



proved that forests of commercial value can be produced over these 

 uplands. It may be that with many more years of experimental 

 study a method may be discovered that will make the production of 

 a crop of trees in the sandhills a surety and a profitable means of 

 utilizing certain areas within this region. As a result of these activ- 

 ities there have appeared a number of publications bearing directly 

 upon the above problems and indirectly including certain more or 

 less fundamental relations that exist in connection with the native 

 vegetation of the sandhills. Bates (3) dealt primarily with the 

 problems involved in the establishment of a forest cover in the hills, 

 but among his studies he included the determination of certain eco- 

 logical factors and their relation to the native and introduced vege- 

 tation. This author recognized four principal "types" in the region 

 about the Halsey nursery. They are ridge, bottom, north slope, and 

 south slope. The different ecological conditions in these types were 

 briefly studied and compared and were found to bear a rather im- 

 portant relation to the forest-planting operations and to the success 

 that was secured in certain experiments. Kellogg studied the for- 

 est belts of western Kansas and Nebraska and published observa- 

 tions (44) that are of certain interest especially in reference to the 

 woody vegetation of the stream courses of western Nebraska. W'ol- 

 cott {77 , 78) has shown something of the inter-relations of the flora 

 and fauna in the various regions of the state including the sand- 

 hills. Warren published a brief paper (69) in which he told of 

 the abundance of certain leguminous species at a few stations in the 

 sandhills of Nebraska. The same writer included with an agricul- 

 tural survey of the state (70) considerable general data in regard 

 to the soil and climatic conditions in the sandhills, and commented 

 briefly with reference to certain forage problems. The paper, al- 

 though of a distinctly agricultural nature, contains some valuable 

 ecological data of state-wide interest. Certain forage problems were 

 studied by Yinall (68) who conducted a number of cooperative ex- 

 periments with ranchmen of the region in the hope of finding some 

 means of supplementing the natural forage yield. More or less suc- 

 cessful experiments were tried with such forage crops as alfalfa, 

 sweet clover, orchard grass, western wheat grass, millet, brome 

 grass, sorghum, etc. Shantz, working mostly in the Great Plains 

 Area of Colorado, investigated (59, 60) the possibilities of deter- 

 mining the capability of land for crop production with especial ref- 

 erence to soil water as this might be indicated by the natural plant 



