• FOEESTRY. 745 



composition ami fertilizer requirements of forest soils, ineludinj; the resnlts 

 secured to date from IG experiments. 



From the investigation as a whole, the author is led to conclude that the 

 fertilizer requirements of forest soils can be detei-miued more accurately by the 

 use of pure chemicals In preference to costly manures. By using pure chemicals 

 the soil requirements of many other substances in addition to lime, potash, 

 phosphoric acid, and nitrogen can be more readily studied. Likewise the results 

 secured from pure chemicals are more uniform than are those securetl with 

 variously constituted manures. In order to counteract the effect of the varying 

 comi)osition of forest soils, it is recommended that each chemical be tested in 

 from 3 to G different jilats. 



Light as a production factor in forestry, R. Reck {Tharand. Forstl. Jahrh., 

 63 (1912), No. 1, pp. Ii-28). — ^A review of the present knowledge of the subject, 

 in which consideration is given to the physiologic and economic importance of 

 light in the forest. 



Lig-ht measurements in spruce stands, E. Ramann (AlUj. Forai it. Jugd 

 Ztg., 87 {191 1), pp. J/Ol-.'/OO). — Since 1005 the author has made measurements of 

 the light intensity in various forests by the use of a seleni)hotometer. The 

 present pajier comprises a study of the measurements secured in spruce stands. 



Chestnut in Tennessee, W. W. Ashe (Tcnn. Oeol. Stirvci/ Bui. 10, Extract B, 

 1912, pp. 33). — This comprises the results of a survey conducted cooperatively 

 by the Forest Service of this Department and the State Geological Survey of 

 Tennessee. The study is presented under the general headings of the com- 

 mercial outlook, distribution, silvical characteristics, diseases and defects, forest 

 types and associatetl trees, growth of individual trees, and management with 

 reference to both pure and mixed stands. 



Varieties of willows, W. P. Ellmore and T. Okey (Jour. Bd. Afir. [London^, 

 18 (1912), No. 11, pp. 906-915). — This comprises economic descriptions of the 

 important basket willows. 



Notes on Western Australian eucalypts, including description of new 

 species, J. H. Maiden (Jour. Nat. Hist, and Set. Soc. West. Aust., 3 (1911), 

 No. 2, pp. 165-190). — These notes are based on field observations made b.y the 

 author in Western Australia during 1909, together with a few additional notes 

 from other sources. 



Tapping experiments with high and low crowned Manihot glaziovii trees, 

 A. ZiMMERMANN (Pflanzer, 8 (1912}, No. 1, pp. 1-6). — The author finds that 

 although the branches of low-crowned trees yield about 12 per cent more rubber 

 than the corresponding trunk parts of high-crowned trees, the cost of tapping 

 is at least 30 per cent higher. The results in general indicate the advisa- 

 bility of growing trees with relatively high trunks. 



The gutta-percha and rubber expedition of the Colonial Economic Com- 

 mittee to Kaiser Wilhelm Land, 1907-1909, R. Schlechter (Die Gullapercha 

 inul Kautschuk Expedition des Kolonial Wirtschaftlichen Komitees wlrtschaft- 

 liclier Ausscliuss der Deutschen Koloniulgesellschaft nuch Kaiser Wilhclins'land, 

 1907-1909. Berlin, 1911, pp. VI+171, pis. iO).— This rei)ort to the German 

 Colonial Society embraces the results of an expedition made to Kaiser Wilhelm 

 Land in 1907 to 1909 to study the gutta-percha and rubber industries of that 

 country. Part 1 consists of a chronological account of the expedition. Part 2 

 contains the information secured relative to the production of rubber, gutta- 

 percha, and other useful plants, as well as botanical notes and maps showing 

 areas of production and the course of the expedition. 



Rubber and gutta-percha, edited by W. R. Dxtnstan (Colon. Rpts., Misc. 

 [Gt. Brit.], 1912, No. 82, pp. IV-\-263-'i-'i7).—The reports on rubber here brought 

 together relate chiefly to the composition and quality of the rubber furnished 



