TIMBER: FOEESTEY 



397 



and as the roots soon died of starvation (Sect. 73), they 

 decayed, and the trees fell and were burned. In this way the 

 farms contuiually encroached upon the woodlands, until areas 

 of primeval forest (Figs. 319 and 320) became so rare that 

 few of us have ever seen one. Lumbering operations which 

 at first dealt only with full-grown trees, often centuries old, 

 came to deal witli " second-growth " woods, in which many of 



Tig. 320. Undrained deciduous swamp forest, — ash, elm, and gum 



the trees were hardly more than saplings; In some cases the 

 states in which lumbering was once an extensive industry now 

 import most of their good lumber, part of it from the Pacific 

 coast. In the future far more care must be taken to maintain 

 our existing timber lands and to plant new areas. Lumber 

 must hereafter be partially replaced in construction work by 

 other materials. That which is used in situations where it is 

 subject to rapid decay, as in fence posts and railroad ties, must 

 be treated with chemicals which will protect it from the attacks 

 of the saprophytic fungi which cause wood to rot. 



