TABLE OF CONTENTS. 



PAGE. 



I. Forest influences: Introduction and summaiy of conclusions, by B. E. 



Fernow 9 



Introduction 9 



Suininary of conclusions 13 



General considerations 13 



Difi'erence of meteorological conditions within and without the forest. 14 



Soil temperatures 14 



Air temperatures under the crowns 14 



Air temperatures within the crowns 15 



Air temperature above the crowns 15 



Air temperature in general 15 



Humidity of air 16 



Influence of forests upon the climate of the surrounding country 17 



Influence of forests upon water and soil conditions 20 



Sanitary influence of forests 21 



II. Review of forest meteorological observations: A study preliminary to the 



discussion of the relation of forests to climate. Bj^ M. W. Harrington. 23 



The nature of the problem 23 



~ Systematic observations in forest meteorology 26 



France 27 



Germany 30 



Sweden 31 



Austria 33 



Objects and methods 35 



Soil temperatures 40 



Temperature of the air in the interior of forests 51 



Annual range 51 



Monthly range 53 



Deciduous and evergreen forests 58 



Temperature in the tree-crown and above trees 61 



Temperature gradients 68 



Temperature above forests 69 



Tree temperatures 72 



Vegetation and air temperatures 76 



Theoretical calculation of heat absorption 80 



Temperatures in woods, glades, and plains 83 



Conclusions regarding temperatures within and without forests 88 



Temperatures in wooded and treeless territories 89 



Relation of evaporation to forests 96 



Forests and humidity 1*^2 



Rainfall in, above, and near forests ^*^ 



Precipitation over wooded and treeless districts HI 



Forests, wind, and storms 118 



Influence of forests on fogs and clouds 121 



Influence of forests on hailstorms and blizzards 121 



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