372 JOURNAL OF FORESTRY * 



those yielded by Nardiis stricta on the treeless grasslands), and 

 then cut down the trees. After 28 years, each birch yields 2.8 cubic 

 meters of wood, aside from branches. In short, these observations 

 hold out the promise of obtaining 400 cubic meters of wood in 28 

 years and at the same time good hay crops. 



These results were obtained on grasslands which were very irreg- 

 ularly planted with birch trees, the roots of which spread out near 

 the surface of the soil and deprived it of moisture. The falling oft 

 in the hay crop is probably due to shortage of water when the roots 

 of the trees interlaced in the twentieth year. If, however, instead of 

 birches the grassland is planted with deep-rooted alders, no such 

 effect was observed. Around the alders the vegetation was of better 

 appearance than around the birches, and came up close to the tree 

 trunks without any reduction in height or change in color, while 

 around the birches the vegetation was weaker and discolored. Al- 

 though the upkeep of high forest alders, as compared with that 

 demanded by birch trees, is greater, the economic advantages of 

 planting grasslands with alder were brought out clearly. With 220 

 alders per acre, a good hay crop may be maintained without manur- 

 ing and without any hindrance to the growth of the grass and the 

 use of the reaper. The trees may be replaced every 14 or 15 years 

 without injuring the grassland by planting young trees 5 or 6 years 

 old in the clear spaces 7 years before felling the old ones. 



Anticipating the objection of insufficiency of sunlight on a piece 

 of grassland planted with trees, it is stated that in a wet climate the 

 cutting ofif of the light by the trees may be a serious drawback, but in 

 a dry climate, where excessive sunshine results rather in burning the 

 grass than promoting the formation of chlorophyll, the planting of 

 trees, as has been shown, proves beneficial. 



The importance of the potassic and phosphatic substances re- 

 turned to the soil by the large quantities of dead leaves of a 17 to 22 

 vear old forest should also not be overlooked. 



