50 FIRES. 



nite period of time. A second presumption is that as a tree died from 

 age, disease, or otlier cause, no new tree could take its place on account 

 of the system of forest burning. Therefore, what had made the valley 

 groves open and the mountain forests park-like, would finally have 

 destroyed the forests and exterminated them entirely. If we undertake 

 to imagine the open forests of the Sierra to have been produced by 

 this constant burning, we cannot escape from assuming a long period 

 of time for the production of the result. We cannot but believe that 

 the present features of forest reproduction in the Sierra have existed 

 since the species of trees now prevailing existed. Prom this we can 

 realize the time of the process likely to have been necessary to 

 I'.roduce the present Sierra Nevada forest. A confirmation of the 

 opinion that the open meadows and park-like forests of the Sierra 

 were produced by Indian burning of the forests is found in the oak 

 openings of the central western states, including Tennessee and 

 Kentucky. When the Indians were driven out, and the annual fires 

 set by them late in the fall in .these oak openings ceased, the openings 

 grew up to forest just like other surrounding woods. The strong 

 reproductive power of the Sierra Nevada forest, especially throughout 

 the mam timber belt, and the way the young trees come up when 

 sheep and fires are kept out, practically force the opinion upon us 

 that the open mountain meadow and open forest are the result of 

 man's work. There is a well-known tendency in dry climates for 

 arboreal vegetation to be scattering and open. This is reasonably 

 assumed to be due to lack of sufllcient moisture to support any denser 

 natural growth than exists. In the Sierra foothills we can see this 

 illustrated. The point where trees first commence in these foothills 

 always shows a very scattering open growth that cannot be considered 

 a forest. As the elevation of the hills increases the rainfall increases 

 and the heat diminishes. The tree growth shows the change of climate 

 by an increased density of growth and increased value of timber up 

 to from six to eight thousand feet elevation. At or near the latter 

 elevation conditions become less favorable for trees generally. That 

 point passed, inferior timber varieties take the place of the great 

 Sierra timber trees. This can also be seen in the cross-range of the 

 Tehachapi, where the rainfall is less than in the Sierra Nevada. The 

 tree growth is less dense and of less valuable species at the same 

 elevation in this range. A large proportion of the Australian forests 

 have this open form of growth. We should from these facts reserve 

 our jud.gment on the cause of the open character generally of the 



