DESCRIPTION OF PLATES. 



Plate I. Frontispiece. — Denuded lands occupied by cactus deserts, near El 

 Rancho, eastern Guatemala. 



Plate II. Denudation and erosion at Cahabon, in eastern Guatemala, a region 

 naturally covered with heavy forests. 



Plate III. Mountain sides terraced for corn and wheat, district of Quezalte- 

 nango, western Guatemala. 



Plate IV. Denuded mountains in eastern Guatemala partially reforested with 

 scattering pines ; tropical vegetation in the deeper valleys. 



Plate V. Valley in open pine forest with advancing growth of tropical trees, 

 Cahabon district, eastern Guatemala. 



Plate VI. Tropical growth in a reforested valley like that shown in Plate V ; 

 dense shade excludes the grass and puts an end to fires. 



Plate VII. Denuded, fire-swept "slopes above the valley of Salama, Guatemala, 

 reforested with scattering pines. The clouds are over the oak-forested 

 mountains in the distance. A column of heated air rising from a denuded 

 district can often be seen to absorb the clouds which drift over from a 

 neighboring forested area. 



Plate VIII. Fig. 1. — Pine forest and bunch-grass on the upper slopes of Vulcan 

 de Agua, Guatemala. With grass enough to burn, even large pines may be 

 killed by fire and the forests driven back from areas they have already re- 

 occupied. Fig. 2. — Pine forest inside the rim of the crater of Vulcan de 

 Agua, Guatemala. 



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