88 Canadian Forestry Journal. 



rainfall 1 1.5 inches ; drought is therefore not much to be feared here 

 but westward the danger increases. From Regina westward to 

 Medicine Hat and northward to Saskatoon, there are very few 

 rainfall records of over a few years, but there is fair evidence 

 that the average annual precipitation over this area nowhere ex- 

 ceeds 15 inches, and at many points is less than that amount. By 

 reference to the table it will be seen that the records of 18 years 

 indicate an average rainfall of 11 inches in Saskatchewan, and 12 

 inches in Alberta, which, with a snowfall of about 55 inches, gives 

 a total precipitation of 16 or 17 inches over the larger part of Sas- 

 katchewan, and 17 or 18 inches in Alberta. But it is to be re- 

 membered that the seasonal precipitation in the far west is very 

 variable. At Calgary in 1892, the total precipitation of the year 

 was but 7.91 inches, while last year it was 34 inches. For five, 

 years the rainfall has been ample in this region, but for many 

 years prior to 1897, it was scant, and in several of the years irri- 

 gation appeared necessary for successful crops. We mav fairlv 

 assume that there will be a return to the dry conditions, and that 

 the Government is acting in a most judicious manner in providing 

 for irrigation in parts of Alberta. 



" The writtT is of the opinion that the Chinook has played an 

 important role in producing a treeless prairie land in Southern 

 Alberta and Assiniboia, and that the tendency for wooded lands in 

 Northern Alberta, and northward, is largely due to the dimish- 

 ing frequency of the Chinook with increasing latitude. The effect 

 of the Chinook in Southern Alberta and Assiniboia is to keep the 

 prairies almost bare of snow during the winter, and to leave it 

 quite bare during the early spring, while farther north, as the 

 Chinook is less frequent, the snow lies deep in winter, melts and 

 waters the ground in early spring, providing moisture for trees 

 at a time when moisture is most beneficial. Observation appears 

 to warrant the statement that rainfall is much more variable near 

 the mountains than it is farther east, also in southern portions of 

 the Territories than in northern portions. In the Territories 

 north of Edmonton, values of rain and snow have been dedu.ced 

 from between 6 and 10 years observations, and from these it ap- 

 pears probable that the normal precipitation throughout Alberta 

 and northward into the Mackenzie River basin is not very differ- 



