CONTENTS 



PART I. 



INTRODUCTORY. 



Page. 



The North American Forest , 13 



Forests of Pennsylvania 13 



The Forests and Forestry , . . . 16 



Forestry in Pennsylvania , 17 



The Structure of the Forest, 19 



The Establishment of the Forest, 21 



The Development of the Forest, 23 



The Protection of the Forest, 26 



The Value of Forests , 28 



The Value of Trees , 29 



Deciduous and Evergreen Trees , 30 



The Age of Trees, 31 



The Form and Structure of Trees , '. 32 



1. Form, 32 



2. Bark, 34 



3. Twigs, 36 



4. Buds, 38 



5. Leaves, 40 



6 . Leaf-scars and Bundle-scars , 43 



7 . Flowers , 44 



8. Fruit, 46 



9. Wood, , 49 



PART II. 



MANUAL OF PENNSYLVANIA TREES. 



Identification of Species , 55 



Names of Trees , , 55 



Explanation of Terms and Headings, 56 



How to Identify the Species and Use the Keys, 58 



General Key to the Families , 63 



Tabulation of Genera and Species , 65 



Description of the Families, Genera, and Species, 67 



Glossary , 220 



Index, 225 



(11) 



