Fire is the greatest source of injury to eucalyptus plantations. 

 Both the natural characteristics of the trees and the conditions 

 within planted groves render them peculiarly susceptible to fire 

 injury. The large quantity of litter dry leaves, branches, and 

 shredded bark which accumulates beneath a stand is extremely 

 inflammable. The bark of eucalypts is so thin that the trees are 

 injured even by light surface fires. 



ECONOMIC USES. 



The wood of blue gum is very heavy, hard, strong, and tough, but 

 it is not durable in contact with the soil. It is close-grained, and 

 is split with difficulty after it has dried. It is less elastic than 

 hickory, but it has been demonstrated by mechanical tests that 

 seasoned blue gum timber is very little inferior in strength and stiff- 

 ness to the best second-growth hickory. In appearance it closely 

 resembles the wood of hickory and ash. 



Blue gum timber is utilized for a great variety of purposes in Cali- 

 fornia. The wood is excellent for fuel, and in the treeless valleys has 

 been the chief fuel supply for many years. In southern California 

 the steady demand renders commercial planting for fuel very profit- 

 able. Eucalyptus timber has been extensively used in California for 

 wharf piling. Blue gum piles are in use in nearly every port on the 

 California coast, and extended trial has shown that they resist the 

 attacks of marine borers which destroy timber in sea water longer 

 than other species commonly used for piling. Blue gum timber has 

 also been used to some extent for fence posts and telephone poles. 

 The wood is not suitable for this purpose, however, on account of 

 its short life in the ground. Seasoned posts last a little longer 

 than green posts, and timber cut from the heart is more durable than 

 sap wood. 



Blue gum timber has been used to a limited extent to determine 

 its value for railroad ties. The results thus far obtained indicate 

 that it compares favorably with second-grade pine tie timber. In 

 case blue gum ties gain a place in the market it may be profitable to 

 plant the tree for that purpose. However, if commercial plantations 

 are to be established for ties, sugar gum should be used in prefer- 

 ence to blue gum, on account of its greater strength and its greater 

 durability in contact with the soil. 



In recent years blue gum has been manufactured into lumber, 

 and has come into favor for many uses. Its strength and tough- 

 ness have led to its use as a material for vehicle construction with 

 very satisfactory results. A just appreciation of the qualities of 

 gum timber will encourage extensive commercial planting, and so 

 furnish an important source of hardwood timber supply for the 

 Pacific coast. 



[Cir. 59] 



