THE ART OF THE SECOND GROWTH 



B. A mean summer temperainre (May to August) of 53 

 to 59 degrees Faht. produces the Fir and Spruce zone of Europe^ 

 Asia and America. A mean summer temperature of 59 to 64 

 degrees is productive of Beech, also of White Oak, Maple, Hemlock 

 and Chamaecyparis. A knowledge of the summer mean is essential 

 when introducing exotics. A knowledge of the possibilities of forest 

 growth in a given country implies a knowledge of the mean summer 

 temperature. 



Some very modest trees are unreliable as indicators or ther- 

 mometers (e. g. 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 analogous 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 comes 

 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, Peach,, 

 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 

 themselves any special power of resistance to frost. It is useless to- 

 import seeds from colder climates in the hope of obtaining greater 

 hardiness. 



"E. Species of trees gro'wing in liot 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. 



F. In level countries, at not over 500 feet elevation, the 

 habitation 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 the habitation 

 more on longitudes than on latitudes. In high mountain regions, 

 altitude may produce eflFects 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 amabilis, 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 



