CONTENTS xiii 



Page 



Maxima and Minima 85 



Frost Pockets 86 



Temperature Inversions 87 



Protection from Cold 88 



Temperature Changes 89 



Influence of Vegetation upon Temperature of Air 89 



Temperature in the Forest 90 



Temperature and Periodicity 91 



Isotherms and Boundaries of Vegetation 92 



Temperature Zones 93 



Ocean Currents and Wind 95 



Light 97 



Physio logic-ecologic Effect of Liglit 97 



Assimilation Curves 97 



Formation of Chlorophyll 99 



Germination of Seeds 99 



Position of Shoots in Relation to Light 100 



Anabolism 101 



Photoperiodism 102 



Measurement of Light Intensity 103 



Light Climates 105 



Significance of the Light Factor for Plant Su(-i.)K;gy 107 



Atmospheric Carbon Dioxide 110 



Determination of Carbon Dioxide Content of (he Air Ill 



Water HI 



A. Precipitation 112 



Rainfall 112 



Contrasts in Precipitation 112 



Rainfall in small areas in relation to pl.int (■oianuiiiities. . . .114 



Measuring Rainfall 114 



Duration of Rain 115 



Effects of Heavy Showers 115 



Dew 116 



Snow 117 



Snow-favored and Snow-injured Species 119 



Snow Cover and Plant Communities 120 



Snow-land Communities 121 



B. Humidity 125 



Ilygromorphy, Xeromorphy 125 



Root Suction and Osmotic Concentration 128 



Osmotic Concentration of Cell Sap 129 



Osmotic Concentration of the Soil Water 131 



Measurement of Osmotic Concentration in Soil 131 



Wilting 132 



Humidity of Air and Plant Communities 132 



Measurement of Humidity 132 



Relative Humidity 132 



Fog 133 



Relative Humiditv in Small Areas 133 



