SEASONAL VARIATION IN WATER CONTENT 



AND IN TRANSPIRATION OF LEAVES 



OF FAGUS AMERICANA, HAMAMELIS 



VIRGINIANA, AND QUERCUS ALBA. 



BY 

 Arabel W. Clark, Ph. D. 



With Chart Figures I— XXXIII. 





(Thesis presented to the Faculty of the Graduate School 

 in partial fulfilment of the requirements for 

 the Degree of Doctor of Philosophy) 



CONTENTS 



I. The Problem 106 



II. Work Previously Done 106 



III. Available Methods 106 



A. Transpiration 106 



B. Water Content 107 



IV. Preliminary Problem 108 



A. Location 108 



B. The Problem 108 



C. Apparatus 108 



D. Detailed Method 108 



E. Data and Results HO 



F. Conclusions 115 



V. Present Problem 115 



A. Location and Ecological Conditions 115 



B. Variation and Description of Apparatus 117 



C. Variation and Description of Methods 117 



D. Data and Results 120 



E. Conclusions .•. 129 



F. Practical Application 129 



0> VI. Summary 129 



,rj>, A. Present Problem 130 



^~ B. General Results 130 



"^ C. Conclusions 130 



^'^ VII. Acknowledgments 130i 



