IT -REVIEW OF FOUEST METEOROLOGICAL OBSERVATIONS: A STUDY 

 PRELLMINARY TO THE DISCUSSION OF THE RELATION OF FORESTS 

 TO CLIMATE. 



By M. W. Harrington. 



THE NATURE OF THE PROBLEM. 



Tlie covering of the earth's surface deteriuiues many of the minor 

 features of climate, and especially those features which are of import- 

 ance for agriculture. The insular climate, the coast climate, the desert 

 and prairie climates, the differences between steady winters with con- 

 tinuous snow-covering and variable winters with little or no snow, all 

 have peculiarities that are due to the character of the covering of 

 the earth's surface at or near the station which has the climate in ques- 

 tion. 



A striking illustration of the effect of the surface-covering on climate 

 and weather is seen in the case of a snow- covering. This has been 

 studied recently by an eminent Russian meteorologist, Dr. VVoeikofl', 

 who finds the influence of the snow to be surprisingly far-reaching. It 

 chills and equalizes the temperature; it promotes the passage of bliz- 

 zards and otlier winter storms; it retards the spring; it feeds the water 

 more slowly to the streams; it promotes the continuance of clear, dry 

 weather with high barometric pressure; and it has mauy other effects 

 which are of hardly less importance. 



The forest is to be considered, in its effects on climate and weather, 

 as a special form of surftice-covering. Its effects are of the same order 

 as those produced by a covering of sand, or sod, or water, but the 

 forest effect has some peculiar features which are due to the fact that 

 the covering is elevated to some extent above the soil. This imparts 

 to the soil in some degree the climatic characteristics due to a topo- 

 graphical elevation, and also causes a series of wind-break effects which 

 are not found with the other forms of surface-covering. On account of 

 this distinctive feature, the problem of forest clinuitology separates 

 into two problems, which must be considered each by itself. The one 

 relates to the climate of the interior of the forest, the other to the 

 effects of the forest on the (ilimate of the open country around it. The 

 two are quite different; the first is of relatively little imiiortance ex- 

 cept as it relates to the second. It is the second which is of interest 



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