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) 



