FORESTRY. 747 



diameter measurements of the whole tree and parts suitable for logging; pur- 

 poses. The trees varied from GO to 200 years old. 



The results of this study are presented in tabular form and further tables are 

 compiled with regard to the volume, value, and price iucrenieut for the different 

 age classes studied. 



"■ The electric conductivity of trees, together with contributions to the 

 question dealing- with the causes of lightning stroke in trees, F. Wolff 

 (Xutiinv. ZtscJir. Land u. Forstic, 5 {1901), Xo. 9, pp. J,2.j-.'i71. figs. «).— A de- 

 tailed account of the author's experiments along this line is given and the 

 results secured are compared with other investigations. 



The author conies to the conclusion that the conductivity of trees is extremely 

 variable both as between different species and in the same species during dif- 

 ferent periods of growth. He also concludes that the electric conductivity of 

 the tree is dependent upon the composition of the sap and its fluctuation in re- 

 si)ect to quantity and constitution, rather than upon the content in fat as was 

 formerly advanced by Jonesco. During the present investigations no definite 

 conclusions were reached in regard to the causes of lightning stroke in trees. 



The text is accompanied with several tables and figures, as well as by 

 platted curves showing the variation of conductivity in trees at various seasons 

 of the year. 



On the saw pinching of Japanese woods, F. Koide {B\i}. Imp. Col. Af/r. and 

 Forest)-]!. .Jaixni. J907. Xo. 1. pp. 27-71). — Previous investigations by the author 

 upon this subject were published in 1895 (E. S. E., 7, p. 871). 



The present investigations were conducted to determine whether saw pinch- 

 ing occurs in green trees alone and the causes, as well as to establish numerical 

 relations between the pinch measurement of a disk and its distance from the 

 heartwood. The experiments are described and the results are set forth in 

 numerous tables and further discussed. 



Saw pinching appears to occur with air-dry wood as well as green wood, if 

 it again becomes water-soaked. The higher the tree and the narrower the an- 

 nual rings the smaller the average pinch measure. The pinch measure in the 

 longitudinal measure of the tree shaft was too small to be taken into account. 

 Pinching in air-dry wood is of little consequence when the saw cut Is wide. The 

 cause of pinching appears to be due largely to the resistance of the excess water 

 in the wood cells against the saw, although it may depend to some extent upon 

 the structure of the wood. The formulas as derived by the author as the re- 

 sult of investigations are also explained. 



On the distribution of pressure in various forms of wood disks of Quercus 

 salicina, F. KpiUE (Bui. Imp. Col. A;/): and Forcstrj/. Japan, 1907, Xo. 1, pp. 

 1-25). — The author conducted investigations on the distribution of pressure in 

 tangential and radial directions on disks of wood of various sizes and form, 

 including complete disks, and 3, 4, and 6 cornered pieces of wood. The results 

 of these investigations are here discussed with the aid of numerous formulas. 



Progress report of forest administration in the Punjab for the year 1905-6, 

 E. G. Chester (h'pt. Forest Admin. Punjab. 190.')-G, pp. u.i,). — An account, with 

 tabular data, is given of the operations of the Punjab forest administration 

 for the year lUOS-G, including constituticm, management, protection, sylvicul- 

 tural operations, methods of exploitation, and the financial statement for the 

 year. 



At the close of the year the Punjab forests of all classes comprised a total 

 of 0,075,001 acres. The surplus of revenue over expenditure was 510,702 ruiM?es 

 (about $103,400) as compared with 458,037 rupees for the year 1904-5. The 

 decrease in revenue is said to be due to the free distribution of timber to earth- 

 quake sufferers, 



