FOREST TREES. 87 



tions, or where slate or granites predominate, and utterly 

 fail on limestone, or what are termed rich limestone soils, 

 which some claim to be the case with the chestnut. Some 

 trees appear to require opposition or resistance to root 

 growth in order to keep them healthy, and these kinds do 

 best in stiff clay or on soils filled with loose rocks and 

 similar obstructions. We can usually make a very close 

 guess as to what kind of soil is best adapted to a species 

 if we know the character of that in which it is naturally 

 found most abundant, and for this reason we would not 

 select a clayey soil for the white pine, or a light sandy 

 one for the elm, hickory, or maple. Then again we 

 would much prefer a swamp for the red maple, and a 

 hard, dry and moderately dry soil for the sugar maple. 

 I throw out these hints in order that those who may have 

 occasion to make selections from the trees described in 

 the following pages, will not overlook whatever I may 

 have to say in regard to their native habitats. 



CHAPTEE XV. 

 FOREST TREES. 



I propose in the following pages to mention all trees 

 indigenous to the United States, so far as known to 

 botanists, also the best known of the exotic species that 

 have been introduced and cultivated to any considerable 

 extent for ornamental or other purposes, but as the 

 limits of this work will not admit of a full botanical de- 

 scription of all the species and varieties, I shall only refer to 

 some of the most conspicuous and familiar characteristics 

 of each, and in language that I hope can be understood 

 by those who are not accustomed to the use of purely 

 scientific terms. Those who may desire a full scientific 



