No. 1, August, 1921] FORESTRY 31 



195. Reuter, M. Die Waldweider. [Forest grazing.] Allg. Forst- u. Jagdzeitg. 96: 

 40-45. 1920. — As a consequence of the feed shortage during the i)eriod of the war, as was also 

 the case in the dry summers of 1893 and 1911, there was a marked increase in forest grazing. 

 The author enumerates the damage to forest growth by grazing animals, and the effect of 

 the latter upon other destructive agents. It is the author's belief that forest grazing will 

 again be reduced to a minimum when normal economic conditions are restored. — Joseph iS. 

 Illick. 



196. RuBNER, K. Baumkronenform und Schattenfestigkeit. [Crown form and tolerance.] 

 Forstwiss. Centralbl. 42: 249-258. 1920. — Mayr's law, that a given species needs less light 

 in a warmer climate and more light in a cool climate, is not entirely true. Several trees, 

 notably Scotch pine, spruce, larch, and oaks, increase in tolerance eastward and northward 

 from western Germany, and are also more tolerant at the higher elevations than on the plains. 

 There appears to be a fairly constant relationship between tolerance and form of crown, 

 not only for the species mentioned but also for others, such as the birch, aspen, and Austrian 

 pine. Toward East Prussia and western Russia the crowns become narrower, the trees stand 

 closer together, their boles are more cylindrical, and height growth is more rapid. Moreover, 

 in contrast to conditions prevailing in western Germany, natural reproduction is abundant 

 under the shade of the old stands. — W. N. Sparhawk. 



197. RuBNER, K. Die Krisen am Holzmarkt. [Crises in the timber market.] Forstwiss. 

 Centralbl. 42 : 353-360, 405-415. 1920. — The author discusses the relation of the timber market 

 to general economic conditions, and traces the fluctuations in timber imports and in timber 

 prices in the important German states, in relation to cycles of general prosperity and depres- 

 sion. This relationship began with the development of a world trade in timber, in the 1860 

 decade. Timber has certain advantages over coal, iron, or wheat as an indicator of economic 

 conditions, because coal and iron production and prices, being manipulated by syndicates, 

 do not respond readily to changes in the ratio of demand to supplj', while wheat production 

 and prices depend very largely on crop conditions and to some degree upon the tariff. Tim- 

 ber does not have to be marketed if conditions are unfavorable except in certain cases, such 

 as forced cuttings due to wind or other damage. — W. N . Sparhawk. 



198. RuBNER, K. [Rev. of: Bjorkenheim. Beitrage zur Kenntnis einiger Waldtypen 

 in den Fichtenwaldungen des deutschen Mittelgebirges. [Studies of forest types in the spruce 

 forests of central Germany.] Helsingfors, 1917.] Forstwiss. Centralbl. 42: 457-463. 1920. — 

 Bjorkenheim, working along the same lines as Cajander, presents the results of studies of 

 more than 200 spruce stands in the mountain forests of central Germany. He classifies the 

 stands on the basis of the characteristic predominant plants in the surface vegetation 

 {Oxalis, Oxalis-Myrtillus, Aira, Myrtillus, Calamagrostis). This vegetation, being a resultant 

 of the various site factors, is a very good index of the wood-producing power of the site, as 

 the author shows by correlating height, diameter, and basal area growth of the spruce with 

 the sub-types described. These different sub-types call for different silvicultural treat- 

 ment. — Rubner says that such conclusions are more applicable to the extensive virgin forests 

 of Finland, northern Scandinavia, and northern Russia, than to the artificial forests of Ger- 

 many where the natural vegetation has been greatly modified by neighboring cultivation 

 of meadows and agricultural crops. Bjorkenheim's studies were made in the less disturbed 

 mountain forests. Such studies of the forest vegetation are decidedly worth while because 

 of the new points of view they afford, even though such positive results as those of Cajander 

 and Bjorkenheim cannot usually be expected. — IF. A'. Sparhaivk. 



199. ScHADELiN, W. VON. Beitrage zum Kapital Spatfrost, [Contributions to the dis- 

 cussion of late frosts.] Schweiz. Zeitschr. Forstw. 71: 329-344. 4 pl- 1920. — Late frosts 

 are common in the higher elevations of Switzerland in the region between the Jura and the 

 Alps, and have a noticeable effect on the forests. An area of about ISO m. by 110 m. at an 

 elevation of 559 to 581 m., was clear-cut. The natural reproduction was seriously frost injured 

 due to the cold air drainage whereas the timber protected the young growth under it. Planted 



