PERIODICAL LITERATURE 



SOIL, WATER, AND CLIMATE 



The retrogression of the upper hmits of vege- 

 Vegetation Limit tation in the Eastern Alps, and the decline or dis- 

 hi the Alps and appearance in many places of the dairy industry 

 Its Significance which formerly depended upon the high moun- 

 tain pastures, is due partly, perhaps, to climatic 

 changes, but the acts of man are more responsible. The cutting of the 

 Alpine forests for their timber, and the burning of brush-covered areas 

 in order to improve pasturage, exposed the Alpine meadows to the 

 winds, with the result that grass and practically all other plant growth 

 gradually disappeared. Overgrazing by cattle and, later, more serious 

 overstocking with sheep, prevented reproduction of the trees which 

 were needed to shelter the meadows, and also injured the forage cover, 

 so that many areas which once supported large numbers of stock have 

 become barren wastes. These conditions can be remedied only by 

 establishing protective belts of brush and trees, which will be a long 

 and costly task. W. N. S. 



Hauber. Der Ruckgaiig der Vegetationsgrenzen in den Alpen und ihre 

 Bcdeutung fiir die Almzvirtschaft. F'orstwiss. Centralbl.. 42:436-443, 1920. 



Fifteen stations have been installed for the 

 Temperature purpose of closer study of the relation between 

 Observations, air temperature and seed production along the 

 Forests of northern timber line in Norway. It has been 



Norway, ipig found by borings and silvical study that success- 

 ful natural reproduction periods are about 100 

 years apart, not because the seed is produced so seldom but because 

 favorable temperature conditions for blossoming and seed ripening re- 

 quire three seasons of relatively high air temperature. Dr. Hagem of 

 the Bergen Experiment Station has found by testing pine seed from 

 different parts of Norway, and that from the northern timberline in- 

 cluded, that the latter is practically worthless and that a mean air tem- 

 perature of at least 10.5° C. must prevail during the period of ripen- 

 ing. During some seed years the average temperature often falls be- 

 low this in the northern section. J. A. L. 



Krogness, C. Om tempcratunnaalingcrne i skogsdistricterne i Nord-Norge 

 sommeren 1919. Tidsskrift for Skogbruk, supplement, 28 : Nos. 9 and 10, 39-56, 

 1920. 



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