192 Forestry Quarterly. 



Growth may be started artificially by removing the integuments 

 or by modifying them so that they no longer exclude the essential 

 substances. Thus in the case of Mesquite, Prosopis juliflora, 

 ether dissolves the oily deposits of the seed coat and allows 

 germination to take place. The application of heat, while soak- 

 ing seeds, hastens germination, but its effect is very variable in 

 different species, in the same species in different parts of its 

 range, or even in different parts of the same crop. 



R. T. F. 



Longevity of Seeds. The Botanical Gazette, 1909, No. 1. 



SOIL, WATER, AND CLIMATE. 



A resume of the present knowledge as re- 

 Forest gards nitrogen supply to tree growth points 



and out that, according to Schroeder, atmos- 



Nitrogen pheric precipitation carries annually 10 to 



Supplies 1 1.5 lbs. of nitrogen per acre to the ground ; 



that the annual consumption for wood pro- 

 duction by beech, spruce, fir, birch, is 9.3, 11.9, 12, and 6.5 re- 

 spectively, while the litter returns to the soil annually 40 lbs. per 

 acre under beech, 28.8 under spruce, and 26.1 under pine. The 

 litter then plays an important role. 



Professor Henry of Nancy (See Quarterly, Vol. II, 173, etc.) 

 who has for years studied the question and assigned to bacteria 

 living in the litter nitrogen gathering capacity, publishes addi- 

 tional material in the Journal d'agriculture pratique, 1907. 



On a sand dune planted in 1850 with Pinus maritima, in 1906 

 a fine forest was found, the soil of which in a sample taken to a 

 depth of 6 inches developed over 7 tons of organic substance, 

 with nitrogen contents of 1.5%, i. e. 248 lbs. per acre or 4.5 lbs. 

 of accumulation per year. In another case, under a specially 

 made plantation of pine, after 9 years the accumulation was 7.2 

 lbs. per year. 



