484 JOURNAL OF FORESTRY 



soil. It is stated that railroad fires start usually within a distance of 

 25 yards, only rarely as far as 50 yards from the track. Cleared fire 

 guards, which must be kept free from inflammable material or culti- 

 vated, are also used. Stone fences are cited as most effective. A con- 

 siderable discussion on the use of isolating belts, which are now and 

 then used in Germany, but not yet in Sweden, leads to the conclusion 

 that such would be mostly too expensive to create and maintain, the 

 damage by fire being less than the expenditure. 



Such belts should consist of forest growth to intercept the burning 

 embers. The one interesting statement is made that, contrary to usual 

 belief, conifers are better adapted for this tire screen than deciduous- 

 leaved trees, which, when the foliage is dry, are inclined to spread fires ; 

 an open stand of conifers, in which dry branches are removed, is most 

 effective. Such belts are to be planted 30 or 40 yards from the right of 

 way ; the expense the committee proposes to charge to the railroads. 

 They are to be managed under short rotations for pit props, pulpwood, 

 poles, posts, and fuel wood. 



O. N. 

 Skogsvards Foreningens Tidskrift, January, 1917, pp. 69-76. 



The laws of the life duration of seeds at 

 Seeds various degrees of temperature is of consider- 



of able importance in forestry, particularly in de- 



Life Duration termining a safe temperature to employ in kiln 

 drying the fruits of forest trees prior to the 

 extraction of seed and the duration of storage. Foresters have come 

 to a general understanding that temperature in the extraction of seed 

 should be gauged with extreme care. Haack recommends a constant 

 temperature of 122 degrees F. as the permissible heat for green cones, 

 and if the cones are dry when gathered or have been thoroughly 

 cured a temperature of 131 degrees F. is permissible. Recent investiga- 

 tions appear to prove that the seeds of most species will withstand 

 a considerably higher temperature for several hours, provided they 

 have been suflficiently dried beforehand. 



In the interesting paper by J. F. Groves the author gives a very 

 complete historical review of previous investigations that have been 

 made on the laws of the life duration of seeds at high temperatures. 

 Special apparatus was devised to obtain constant temperatures and the 



