1917] FORESTRY. 147 



Ornamental windbreaks. — Evergreens are grouped with small trees and 

 flowering shrubs, W. E. Uontkagek {Mo. Bid. Ohio Sta., 2 {IDIT), Xo. 3, pp. 

 82-84, fig. 1). — This paper presents suggestions relative to the use of orna- 

 mental trees in the development of windbreaks for protecting orchards, gardens, 

 barnyards, etc. 



Investigation on the optimum limit of intensity of thinnings, E. Mer 

 (Rev. Eaux et Forets, 55 (1917), Nos. 2, pp. 33-43; 3, pp. 65-72).— In con- 

 tinuation of previous papers (E. S. R., 36, p. 345) the author gives the results 

 secured from thinnings of different intensities in some selected fir stands that 

 were thinned in 1SS6 and in 1899. 



Toxic atrophy, E. A. Woodbuffe-Peacock (Quart. Jour. Forestry, 11 (1917), 

 No. 2, pp. 8S-93). — In this paper the author presents his views relative to toxic 

 atrophy as an important factor in the failure of species to reproduce themselves 

 in woodlands. 



The forests of Quebec, A. Bedabd (Statis. Year Book Prov. Quebec, 1916, pp. 

 414-428). — A short description of the three forest zones in Quebec, including 

 some statistical and economic considerations. 



Notes on some North American conifers based on leaf characters, L. W. 

 DuRKELL (Proc. lotva Acad. ScL, 23 (1916), pp. 519-582, figs. 117).— The author 

 here presents a series of drawings, with descriptive text, of the leaf characters 

 of the arboreal conifers of North America bearing needle leaves, except Pinus. 

 The characters of the same species were found to be constant even though the 

 specimens came from widely separated localities. 



The tulip poplar (Liriodendron tulipifera). — A forest tree of important 

 commercial value for Ohio, A. E. Taylor (Mo. Bui. Ohio Sta., 2 (1917), No. 2, 

 pp. 51-58, figs. 4). — An account of the tulip poplar with reference to its char- 

 acteristics, soil and light requirements, commercial value, and silvical man- 

 agement. 



On the mode of occurrence of latex vessels in Hevea brasiliensis, G. 

 Bryce and L. E. Campbell (Dept. Agr. Ceylon Bui. 30 (1917), pp. 22).— The 

 authors here record a study of the distribution and mode of occurrence of latex 

 vessels as observed in a number of untapped trees at the Peradeniya Experi- 

 ment Station, as well as in trees growing on plantations in several different 

 districts of Ceylon. 



Tapping experiments at Gunong Angsi, F. G. Spring and B. Bunting 

 (Agr. Bui. Fed. Malay States, 5 (1917), No. 4, pp. 111-123).— In continuation 

 of previous work (E. S. R., 30, p. 535) the results of the third season are given 

 on tapping experiments with rubber to determine the relative yields from 

 adjacent and opposite quarters with both daily and alternate tapping. 



The results thus far secured indicate that the yield from adjacent quarters 

 of the tree (double V cuts) is approximately 18 per cent gi'eater than that 

 from opposite quarters of the tree. The daily tapping of adjacent quarters 

 gave 26 per cent more rubber than opposite quarters, while on alternate-day 

 tapping the difference in favor of adjacent quarters was only 9.5 per cent. 

 Opposite quarters not only gave much poorer total yields and higher per- 

 centages of scrap rubber than adjacent quarters but had the disadvantage of 

 having two distinct tapping areas which makes the system much more difhcult 

 both as regards tapping and supervision. 



" Tarwad " bark as a tanning agent, D. B. Limx\.ye (Ranade Indus, and 

 Econ. Inst., Poona, Bui. 1 (1916), pp. 18). — An account of the "tarwad" bark, 

 the product of the perennial shrub Cassia auriculata, with reference to its 

 us© for tanning purposes in India. Analysis of tannin content and methods 

 of collecting the bark are also given. 



