1917] FORESTRY. 837 



The preservation of leafy twigs of the beech, L. A. Boodle {Roy. Hot. Gard. 

 Keiv, Bui. Misc. Inform., No. 6 {1917), pp. 220-231). — Experiments reported by 

 the author indicate tliat leafy twigs of the common beech may be preserved 

 for several months vrith very little wilting by cutting the twigs when the leaves 

 are still green and placing the stems in a solution of calcium chlorid for about 

 a week. Tlie best results wei'e secured by using solutions with specific gravities 

 of 1.4 and 1.2. The lower ends of the twigs were trimmed every day or two 

 to present freshly cut surfaces to the liquid and the twigs were exposed to direct 

 sun for several hours during the treatment. 



The importance of plantation margins, A. Murray {Trans. Roy. Scot. Arbor. 

 Soc, 31 {1917), pt. 2, pp. 156-159). — A short paper on the selection of species 

 for and the subsequent management of forest plantation margins or shelter 

 belts. 



Trees for nonirrigated regions in eastern Colorado, W. J. Morrill {Colo. 

 Agr. Col. Ext. Scrv. Bui., 1. ser.. No. 123 {1917), pp. 20, figs. 6).— A descriptive 

 list of trees and shrubs, including notes on their general behavior in eastern 

 Colorado, is given, together with suggestions on tree planting. 



Forest succession and rate of growth in sphagnum bogs, G. B. Rigg {Jour. 

 Forestry, 15 {1917), No. 6, pp. 726-739, figs. 3).— A discussion of forest succes- 

 sion and rate of growth in six bogs of the Puget Sound region and four in 

 Alaska, based on field observations conducted for several years. 



Aspen as a permanent forest type, J. M. Fetherolf {Jour. Forestry, 15 

 {1917), No. 6, pp. 757-760). — In this paper the author brings out the more per- 

 manent features of aspen as a type, based on its behavior in habitats like the 

 semiarid intermountain region. 



The pitch pine, L. Piccioli {Ann. R. 1st. Sup. Forestale Naz. Firense, 2 

 {1916-17), pp. 401-431, pis. 4, figs. 6). — An account of the various species of 

 pine commonly known as pitch pine with reference to their distribution, 

 anatomical characters, technical properties, and culture in Europe. The ac- 

 count is prepared with special reference to the selection of species adapted to 

 Italian silviculture. 



Notes on white pine 4-year transplants, S. N. Spring {Jour. Forestry, 15 

 {1917), No. 6, pp. 761, 762). — A growth record is given of white pine seedlings 

 grovsTi from three seed beds which were sown broadcast with different quan- 

 tities of seetl. 



The density of stand and rate of growth of Arizona yellow pine as in- 

 fluenced by climatic conditions, F. Shreve {Joiir. Forestry, 15 {1917), No. 6, 

 pp. 695-707, figs. 6). — A contribution to our knowledge relative to the influence 

 of climate on tree growth, based on observations and measurements made in 

 the Santa Catalina Mountains in southern Arizona. Data are given showing 

 the differences in population of the Arizona yellow pine at different altitudes, 

 the differences in the character of the populations, and the differences or simi- 

 larities in the rate of growth at the several elevations. 



Probable error in field experimentation with Hevea, O. F. Bishop, J. 

 Grantham, and M. D. Knapp {India-Rubber Jour., 54 {1917), No. 15, pp. 13-16, 

 19-22, fig. 1). — A review of recent literature on the subject, including actual 

 records of experiments in Sumatra showing variations that may occur among 

 carefully chosen experimental plats and the need of applying probable error 

 methods. An example is given of the application of the probable error method 

 to a series of 26 tapping experiments which were carried on in triplicate. 



Seed selection in the cultivation of Hevea brasiliensis, T. Petch {Roy. 

 Bat. Card. Kew, Bui. Misc. Inform., No. S {1917), pp. 118-120). — A brfef ac- 

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