PREFACE 



Trees are among the commonest and most conspicuous objects 

 of nature. The numerous products derived from them are very use- 

 ful, often indispensable. In all ages trees and grasses have been 

 the most important products of the soil. A dense and valuable tree 

 growth covered originally almost the entire area of Pennsylvania. 

 About 278 species of trees and shrubs are native to this State, of 

 which number 125 are trees. The number of native representatives 

 in the present forests is the same as in the original forest. While 

 the number of representatives remains the same, yet one finds a 

 marked difference in the degree of their abundance, and in their age, 

 size, form, density, quality, value, and productivity. The original 

 forest of the State was large, dense, and extremely productive. The 

 present forests are small, open, and very unproductive. Each gener- 

 ation of mankind has seen a smaller, more open, and less productive 

 generation of forests. It is not a prophecy, but the statement of 

 a fact, when we say that the source of our timber supply is becom- 

 ing an acute and vital question. Fast- vanishing forests and ever- 

 rising lumber prices are couriers of this fact. The Federal and some 

 State Governments have already inaugurated policies to offset the 

 present destructive tendency in our .forests by starting constructive 

 work. To date no state has made a greater advance in forestry than 

 Pennsylvania. She has, however, just started on this useful mission. 

 The men who are directing her forest policies are endeavoring to 

 lay a substantial foundation upon which a stable superstructure may 

 be reared. In order to accomplish this it is necessary to have the 

 co-operation of the citizens of the State, especially the woodland 

 owners and managers. Forestry needs the support of public senti- 

 ment. No substantial and permanent advance is insured until our 

 citizens understand the fundamentals of forestry and can distin- 

 guish the important timber trees from the inferior weed trees. It 

 is hoped that the sphere of usefulness of this bulletin will not be 

 limited to woodland owners and managers, but will extend to lay- 

 men, students, and botanists. 



Part I is intended for the layman and the beginner of forestry. A 

 careful perusal of this part will enable one to comprehend Part II 

 more fully. The former comprises abstracts from the author's lec- 



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