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NATURALIST'S GUIDE TO THE AMERICAS 



climax forest type or association since, 

 when necessary, cut-over forest areas 

 are closed to grazing during the regener- 

 ation period. Further, grazing has in 

 many cases aided regeneration of the 

 forest by improving the seed bed, 

 trampling the seed into the soil, and 

 lessening the competition through crop- 

 ping of associated species. The aid to 

 more rapid revegetation by properly 

 regulated grazing has assisted in les- 

 sening erosion and in improving water- 

 shed protection. 



Regulated grazing in the National 

 Forests is further supported by the 

 strong argument that it is beneficial in 

 the control of forest fires. The value 

 of grazing as a means of fire protection 

 is realized in the utilization of the annual 

 growth of grass which, if not so disposed 

 of, becomes dry and inflammable and a 

 serious fire hazard. The extensive work 

 in forest fire prevention and suppression 

 on the National Forests is a very im- 

 portant factor in promoting and main- 

 taining climax types of forest vegetation. 



In rendering the secondary uses com- 

 patible with the primary uses of the 

 National Forests, and in harmonizing 

 the secondary uses, it frequently be- 

 comes necessary to close areas to graz- 

 ing as, for example, watersheds which 

 comprise important sources of munic- 

 ipal water supply; recreational areas 

 and those of unusual scenic attractive- 

 ness, such as the National Monuments; 

 areas on which the forage on the range 

 is needed for important game animals; 

 and some forest areas in the course of 

 regeneration. Many of the areas shown 

 on the map of the National Forests 

 (figs. 1 and 2) are in a semi-natural condi- 

 tion and fall within this category. 



9. FIRES IN RELATION TO THE 

 BIOTA 



By R. H. Wolcott 



For a long time previous to the de- 

 velopment of ecology as a science fires 

 have been recognized as an important 

 ecological factor. Many scattered ref- 

 erences to their efifects upon animal 



and plant life are found in all kinds of 

 literature, but few of these are based 

 upon exact data or represent the results 

 of continued observations. 



A very full discussion of forest fires 

 as to their kind, occurrence, causes, 

 and methods of prevention will be 

 found in Chapter VII of Graves' Prin- 

 ciples of Handling Woodlands or in Chap- 

 ter XV of R. C. Hawley's The Practice 

 of Silviculture. At the end of these 

 chapters there is given a very excellent 

 bibliography on forest fires so that an 

 enumeration of these points seems out 

 of place here. 



The damage caused by forest fires on 

 this continent is enormous. Plummer' 

 makes the statement that 



Forest fires in the United States have 

 caused an annual loss of about seventy 

 human lives, the destruction of trees 

 worth at the very least $25,000,000 and 

 the loss of stock, crops, buildings and 

 other improvements to the amount of 

 many millions more. To these must be 

 added enormous losses from the destruc- 

 tion of young tree growth, deterioration 

 of the soil, damage to water courses and 

 adjacent property by low water and 

 flood, interruption of business and de- 

 preciation of property. 



When to the loss by forest fires is 

 added the loss from prairie and other 

 fires it is seen that the total loss to this 

 continent from fires up to the present 

 time amounts to several billions of 

 dollars. 



As to the injuries due to fires, we may 

 mention first, the destruction of the 

 plants themselves with whatever loss 

 that entails; second, the destruction of 

 the humus in the soil with the resulting 

 loss of fertility; third, the destruction 

 of lumber or other valuable products; 

 and fourth, the accumulation of dry 

 material which may serve to feed suc- 

 ceeding fires. In many of the forested 

 parts of the country the debris which 

 has accumulated from one fire after 

 another has resulted in the periodical 

 burning over of areas for long periods of 

 time. 



1 Plummer, Fred G. Forest Fires, Bull. 117, 

 U. S. Forest Service, Washington, 1912. 



