82 Forestry Quarterly. 



but under such conditions that the amount due to these thirty- 

 days is only about 6 to 10 inches, whereas the annual variation 

 of the total rainfall is often 60 inches. Before deforestation "rain 

 fell on many calm afternoons, because the presence of the moist- 

 ure transpired by the trees was sufficient, by increasing the hu- 

 midity and decreasing- the pressure, to cause slight showers." 

 The rains thus caused are, however, very local, and the author of 

 this paper does not recommend any great work or expense in 

 planting trees with the idea of improving the climate generally. 



R. DeC. Ward, in Bulletin American Geographical Society, 1908, p. 746. 



SILVICULTURE, PROTECTION, EXTENSION. 



It is stated that poplars furnish in France 



Cultivation an annual wood product valued at $6,000,- 



of 000, Paris alone consuming annually about 



Poplar. 7 million cubic feet. Thus, according to 



Breton-Bonnard's volume he peuplier, the 

 poplar is next to oak, the most useful tree, and the only one which 

 he who plants it may harvest. Dr. Thaler discussing the propa- 

 gation of poplars advocates the use of seed rather than the cus- 

 tomary cuttings. The seed ripens the end of May to beginning 

 of June (P. Canadensis a fortnight later than P. alba). It should 

 at once be sown in a seedbed thoroughly watered, the seeds in 

 their wool being placed in thin layers on the ground, pressed in, 

 and covered with very fine soil, so that the wind will not move 

 them but the wool still remains visible. The seedbeds are 

 shaded by placing beech brush along their sides, and are daily 

 watered several times with a sprinkler, and this treatment is 

 continued some time after the little two-leaved seedlings have ap- 

 peared. A dose of lime dust protects them against snails and 

 worms. Transplanted after a year the transplants made a growth 

 of over five feet the first summer. 



The male and female plants of P. Canadensis, grown from cut- 

 tings, show differences, the males having a gray bark, the female, 

 yellow bark ; the males have larger leaves, and at the tip for a 

 foot, or foot and a half there are four diagonally opposite small 

 cork wings which are lacking in the females. 



Anzucht von PappelsdmUngen. Allgemeine Forst- und Jadgzeitung, 

 1908, p. 378. 



