March, 1920] FORESTRY 77 



tion based on experience, (2) by pro-rating the values for each age class for the dilTerent spe- 

 cies, in accordance with present relative commercial values. An example is presented for 

 northern Idaho and Montana. — E. N . Munns. 



526. Clifford, J. D. Effect of thinning on a young teak plantation. Indian Forester 45: 

 16-18. 1919. — An acre of 17-year-old teak, 30 feet in height, was thinned in 1913 and remeas- 

 ured and compared with the check plot in 1918. The5-year girth increment per tree amounted 

 to 3.49 inches on the thinned area and 2.73 on the unthinned, the mean annual increment being 

 0.70 and 0.55 inches respectively. On the thinned plot eleven more trees attained a girth of 

 two feet in five years than was the case on the unthinned, while the excess girth amounted to 

 272 inches. This first thinning took 40 per cent of the stems, while the second, in 1918, took 

 10 per cent of those remaining. Remeasurement is planned for 1923. — E. N. Munns. 



527. Cremata, Merlino. Cercas alambradas y setos en Cuba. [Fences and hedges in 

 Cuba.] Revist. Agric. Com. y Trab. 2 : 259-272. 29 fig. 1919.— Chapter one of this article 

 gives a list of some sixty kinds of wood that make good posts. It includes a brief description 

 of the tree and the wood, notes on distribution, history, nomenclature, etc. Chapter two deals 

 in the same way with trees that may be planted as living posts. — F. M. Blodgett. 



528. Crevat, Jules. Production d'une plantation de pins noirs d'Autriche. [Yields 

 from a plantation of Austrian pine.] Compt. Rend. Acad. Agric. France 1919:32. 1919. — 

 Brief note on the methods of establishing a plantation of Austrian pine and the yields to be 

 expected from it. — E. A. Bessey. 



529. d'Aboville, P. Determination du diametre au milieu du tronc de l'arbre sur pied. 



[Determination of the diameter at the middle of the trunk of a standing tree.] Rev. Eaux et 



For£ts 57 : 117-120. 2 fig. 1919. — If d is the diameter of a tree at the height of the observers 



eye, d' the diameter at half the height of the tree, and / the coefficient of form, then d' = df. 



If the observer stands at a distance from the tree equal to half its height less the height of the 



n' 

 eye above the ground, then / = 1.4 — , when n' and n represent, respectively, the apparent 



n 



magnitudes of d' and d on a graduated scale held horizontally at arm's length. Having ob- 

 tained/, the diameter at the middle-height of the tree, d', can readily be determined from the 

 first formula given. Repeated tests have shown that satisfactory results may be secured by 

 this method. — S. T. Dana. 



530. Dana, S. T. Floods and erosion. Canadian Forestry Jour. 14: 159. April, 1919. — 

 Examples are given of floods and erosion on watersheds where the timber cover has been 

 denuded by destructive lumbering. Another example shows that since forest cover has become 

 established floods and erosion have practically ceased. — E. N. Munns, 



531. Eulefield. Kiefern-Harznutzung. [Production of resin from Scotch pine.] 

 Deutsch. Forstzeitg. 34: 22. 1919. — An experimental operation on 10.86 hectares at Eisen- 

 bach in Oberhesse, employing Scotch pine (Pinus sylvestris) 86 to 110 years old, yielded 1.37 

 kgm. of fluid per tree (299 trees per hectare). Gross returns, at 3 marks per kilogram, were 

 4.12 marks per tree, and expenses were 0.98 marks per kilogram or 1.35 marks per tree. Net 

 return per hectare was 828.80 marks. On a level site the southwest side of the trees yielded 

 the most resin; on a southeast slope, the east side yielded most. The yield was less on hot 

 days and greater on warm, damp days. — W. N. Sparhawk. 



532. Fernow, B. E. [Rev. of: Gill, W. Annual progress report upon state forest admin- 

 istration in South Australia, 1917-18. Woods and Forests Dept. IS p. 1918.] Jour. Forestry 

 17:324-325. 1919. 



533. Fischer, C. Das Verhalten der Sitkafichte in der Oberfb'rsterei Riidesheim, Eezirk 

 Weissenthurm. [Behavior of Sitka spruce.] Deutsch. Forstzeitg. 34: 69. 1919.— Sitka 

 pruces (Picea sitchensis) planted in 1901 are now from 12 to 14 meters high, and others planted 



