24 Characteristics, Structure, Life of Trees 



such a wide range of distribution, through such a variety of 

 climates, that the success depends upon the choice of the 

 locality from \\hich the phmt has been derived or from which' 

 the seed has been secured, for the seed preserves all the 

 characteristics of its mother j)lant. A case in point is the 

 Douglas Fir, ranging from British Columbia to New Mex- 

 ico. Plants of this species, when brought from the humid, 

 mild Pacific Coast do not thrive in the drier, severer climate 

 of the Eastern States; but if grown from seed collected in 

 the dry Rockies, they will succeed. 



It must also be kept in mind that there is considerable 

 variation of climate ex])erienced locally within narrow 

 limits, as for instance, in going from the foot to the top of a 

 mountain, or with change of aspect, and with different 

 exposure to winds. Hence the tree in one place may fmd 

 satisfactory environment, when in close neighborhood, 

 but in a different situation, it may not: the south side of a 

 town is warmer, the northwest colder, but healthier, the 

 southeast most equable, and so on. 



While, therefore, the fact that different species of trees 

 are by nature adapted to certain cHmatic conditions must 

 influence the choice of trees for planting in a given locality, 

 and while the natural adaptation of species to deep or 

 shallow, wet or dry soils is also a matter to be considered in 

 the selection of plant material, we know that soils at least 

 can be adapted to support any tree species and also that the 

 light conditions can, to some extent, be made favorable to 

 the needs of the species adapted to the climate. 



There is one condition of soil which is most favorable 

 to all tree species, namely, a deep, moderately loose, 

 .sandy loam, which ]:)ermits satisfactory aeration and fur- 

 nishes an even water supj)ly. When we speak of trees 

 adapted to other, drier or wetter, more compact or looser, 



