1019] FORESTRY. 153 



inclines, unloading, water transportation, general expenses, and total cost of 

 logging at one operation. 



The ancient oaks of America, W. Tkki.ka.sk {Brooklyn Bot. Curd. M<m., 1 

 (11)18), pp. 4^2-501, pis. 10). — The purpose of the present paper Is to bring to- 

 gether the scattered facts relative to the fossil oaks of America. Leaves of 

 various fossil forms are illustrated, and B key is given to the principal leaf 

 types of the Cretaceous and Tertiary fossil oaks, together with a list of 

 references. 



The ray system of Quercus alba, L. M. Langdon (Hot. Gaz., 65 (1918), No. 4, 

 pp. 313-323, figs. 22).— A study of the ray system of Q. alba, as affected by Buch 

 conditions as the age of the trees, location of shoots in the trees, and vigor- 

 ous or suppressed conditions of growth, indicated that neither the age of the 

 trees nor the location of wood in a tree is an appreciable factor in the modifi- 

 cation of the ray system. The conditions of vigorous and suppressed growth, 

 however, do tend to modify the ray system. A bibliography of literature is 

 appended. 



The relationship between the leaves and latex of Hevea brasiliensis, W. 

 BOBUJOFF (Arch. Rubbcrcult. Nedcrland. Indie, 2 (1918), No. 10, pp. 735-768, 

 figs. 10). — The investigation here reported showed that the current of latex 

 from natural leaves into the stem and back is interrupted at the base of the 

 petiole by a layer of crystals of oxalate of lime, hence it is concluded that no 

 analogy exists between the lactiferous tubes and those conducting organic stuffs 

 (sieve tubes). The latex which exudes from the trunk of the tree as the 

 result of tapping or other injury does not originate from the leaves, and there- 

 fore the leaves are of no vital interest in forming latex. The apparent reduction 

 of latex in the dropping leaf must be attributed to a decrease of the percentage 

 of water. No relationship can be traced between the anatomical structure of the 

 leaf and its petiole and the yield of a given Hevea tree. There also exists no 

 correlation between the size of the leaves and the latex production. 



Rubber seed selection, A. II. Malet (Agr. Bui. Fed. Malay States, 5 (1917), 

 No. 7, pp. 271-274)- — Data presented by the author indicate a wide range of 

 variability in the yield of latex among seedling Hevea rubber trees, thus indi- 

 cating the need of scientific seed selection. 



The girth-increment of sal in regular crops in the United Provinces, E. 

 Marsdkn (Indian Forester, 44 (1918), No. 10, pp. 469-475, pis. 2). — Tabular data 

 are given showing the girth-increment in even-aged crops of sal (Shorea 

 robusta), as determined by measurements in 1913 and in 1918 of 61 sample plats 

 laid out in the United Provinces. 



Determination of increment by stem analysis (Forestry Com. X. 8. Wales 

 liul. 13 (1918), pp. 14, figs. 8). — For the purpose of obtaining authentic infor- 

 mation relative to the growth of species of eucalyptus on the southern table- 

 land of New South Wales, stem analyses of a number of species were made by 

 W. A. W. de Beuzeville. In the present bulletin the figures and conclusions 

 reached for the mountain ash are presented in full, as this species is reported 

 to be the fastest growing species in New South Wales. 



The application of the graphic calculation. — I, On the determination of 

 woodland surveys and the calculation of tree volumes, A. Parascandolo (Ann. 

 R. 1st. Sup. Forest ale Naz. Firenze, 3 (1917-18), pp. 93-136, pi. 1, figs. 40).— This 

 article describes an instrument for facilitating measurement by graphs, and 

 further deals with the application of graphic calculation in measuring wood- 

 land areas and tree volumes. 



Meeting the wood fuel situation, E. Secrest (Mo. Bui. Ohio Sto., 3 (1918). 

 No. 10, pp. 291-299, figs. 5). — A popular paper discussing methods of cutting, 

 burning, buying, and selling fuel wood. 



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