SYLVICULTUEE. 



growth in a given country implies a knowledge of the mean 

 summer temperature. 



Some very modest trees are unreliable as indicators or ther- 

 mometers (i. e. Pinus echinata, Pinus ponderosa). 



C. A species may be grown far from its original habitation, 

 provided that the local climate of the new region is anaiOgous to 

 that of the old. If the exotic comes from a warmer climate^ it 

 should be placed on south slopes with plenty of sun; if it cornea 

 from a colder climate it should be placed in moist soil and on 

 cool aspects. There is no such thing as adaptation of trees to a 

 different climate, or as acclimatization of trees. Walnut, Peacli, 

 and Black Locust have been grown in Germany for centuries, be- 

 cause the climate of naturalization was and is essentially identical 

 with that of the natural habitat of the trees. 



D. Tree specimens of a cold climate do not possess in them- 

 selves any special power of resistance to frost. It is useless to 

 import seeds from colder climates in the hope of obtaining greater 

 hardiness (Douglas Fir from Oregon and from Colorado differ, how- 

 ever, in hardiness). 



E. Species of trees growing in hot localities or else in open 

 stands place comparatively small claims on the fertility of the soil. 

 All species bear shade better when brought to a warmer climate 

 and require more light when brought to a colder one (White Pine). 



F. In level countries, at not over 500 ft. elevation, the habita- 

 tion of a species depends on latitude considerably modified by sea 

 winds. In many countries, away from the ocean, that modification 

 is so strong as to create a dependence of tlie habitation more on 

 longitudes than on latitudes. In high mountain regions, altitude 

 may produce effects similar to those of latitude: it is, therefore, a 

 mistake to label one species as a mountain species and another 

 as a plains' species. In Eastern North America Picea rubens, in 

 Western North America Douglas Fir, also Abies grandis and ama- 

 bilis, bear witness to this truism. 



G. The climatic needs of a species are better characterized by 

 the forest zone than by the latitude or the altitude at which or 

 up to which it grows. Even a knowledge of altitude and latitude 

 combined furnishes insufficient information relative to such cli- 

 matic needs. 



H. If, in a given climatic zone, there are found two neighbor- 

 ing species of the same genus, it is safe to assume that these 

 two species were not mixed originally, but that each had its dis- 

 tinct habitation and that the mixture is due to the action of man. 



.37 



