1920] FORESTRY. 43 



Einpungeni, Znluland. The best results have been secured with Eucalyptus. 

 With a few exceptions, various liinds of conifers tested have not been a success. 



Investigations on the bark-anatomy of Hevea, P. E. Keuchenius {Arch. 

 Ruhhercult. Nederland. Indili, Jt {1920), No. 1, pp. 5-26, figs. 18).— A further 

 contribution on the formation and development of latex rings in Hevea rubber 

 trees (E. S. R., 40, p. 448). The author's method of studying latex rings is 

 described. 



The average yearly increase in latex rings was found to be correlated with 

 the quality of soil and the girth increase, consequently only vigorous stocks 

 should be used for building purposes The rate of formation of latex rings 

 is variable. Periods of strong growth and periods of little development may 

 occur, hence the irregular arrangements of latex rings in Hevea. 



High-yielding trees may deteriorate in yield when the original bark is tapped 

 off, and poor trees may be Improved by the same operation. From the stand- 

 point of latex-ring renewal, a 6-year tapping system is preferable to a 4-year 

 system. 



The latex rings greatly increase in number in the inner part of the bark, 

 lience trt'es Infected with the brown bast disease should be scraped rather 

 than peeled in order to preserve latex rings in the deeper uninfected portion 

 of the bark. At the base of the stem the activity of the cambium for the 

 formation of latex rings is greater than higher up. 



Tapping experiments on Hevea brasiliensis, A. W. K. de Jong {Arch. 

 Ruhhercult. Nederland. Indie, 4 {1920), No. 1, pp. 32-36). — A progress report 

 on tapping experiments being conducted at the Buitenzorg Experimental Sta- 

 tion (E. S. R., 40, p. 843). 



Of the nine tapping systems tried in this experiment, two left cuts on a 

 quarter seem to be the best for the growing conditions at Buitenzorg. 



The influence of heavy tapping on the chemical constitution of the latex, 

 W. H. Arisz {Arch. Ruhhercult. Nederland. Indie, Jf {1920), No. 1, pp. 21-31). — 

 A review of analyses made by L. R. E. Schulz van Vlissingen at the Besoeki 

 Experimental Station. 



In the case of a tree tapped with a circular cut clear to the wood, the pro- 

 portion between the resinous substances and the rubber remained constantly 

 the same, and independent of the concentration of the rubber in the latex. 

 During the first two weeks of tapping the concentration of the organic sub- 

 stances in the serum remained the same, but after this period the constitution 

 of the serum changed through a shortage of organic matter. 



The concentration of the nitrogenous substances in the latex remained about 

 the same during the first few days of tapping, but afterwards decreased as 

 much as one-half of the original concentration. A somewhat smaller shortage 

 of nitrogenous matter also occurred in the rubber. The concentration of the 

 inorganic substances in the serum remained practically the same. 



Kauri-gum industry, R. P. (Jkeville {New Zeal. Gort. Kauri-gum Off. Rpt., 

 5 (1919), pp. 7). — A progress report on the New Zealand Kauri-gum industry, 

 including a financial statement for the year ended March 31, 1919. 



The western larch (Larix occidentalis) on the Brocklesby Park Estate, 

 Lincolnshire, W. B. Havelock {Quart. Jour. Forestry, llf {1920), No 2, pp. 

 96-100). — Growth measurements are given on several lots of larch tree largely 

 planted in 1912 in admixture with various other species. 



European and Japanese larch at Brocklesby Park, W. B. Havelock 

 (Quart. Jour. Forest rg. U^ (1920), No. 2, pp. iO/-i0.3).— Comparative data are 

 given on the growth of several lots of Japanese and European larch planted 

 on the above-noted estate in the spring of 1899. 



