8 UTILIZATION OF CALIFORNIA EUCALYPTS. 
wood is of a yellowish-white color. The sugar gum is one of the 
most drought-resistant of the eucalypts, as has been said, but it is 
unable to withstand frost. 
Gray gum has a very erect habit of growth, whether growing alone 
or in close plantations. The branches are usually few and scattered, 
and the crown open. The wood varies in color from white to light 
brownish red. The value of this species as a tree for planting in 
California has only come to light recently. It apparently makes a 
somewhat more rapid growth than red gum and withstands heat and 
frost fully as well. 
Manna gum has an erect habit. In color the wood varies from 
light brown in the sapwood to a yellowish white in the heartwood. 
This species withstands low temperatures as well as the red gum. 
It can be grown on land and under conditions so unfavorable that 
many of the other species whose wood is more valuable would barely 
live and make only an inferior growth. 
CHARACTERISTICS OF THE WOOD. 
The wood of the eucalypts, unlike that of our northern-grown 
oaks and hickories, has no distinctive alternate bands of spring and 
summer wood. On this account the age of the trees can not be 
determined by counting the rings on a cross section of the stump. 
Bands of wood of different colors and densities can be distinguished 
on a cross section of eucalyptus, but they are often not continuous, 
and several may occur in a year’s growth. The fibers of the wood are 
much interlaced, making it tough and more difficult to split for fuel 
than most woods. The grain is often irregular, which makes the 
wood liable to chip under the planer, but gives it a very pleasing 
effect when it is smoothly finished. When first felled, the eucalypts 
contain a large amount of water; often more than half the weight of 
the green wood is made up of water. Green eucalyptus logs sink 
immediately. This large amount of moisture and the irregular 
structure of the wood make eucalyptus lumber difficult to season 
properly. In color the wood of the eucalypts varies widely, as has 
been indicated, shades of yellow, brown, and red predominating. In 
hardness and dry weight there is also a wide range. 
STRENGTH. 
The material used in the eucalyptus tests was in every case selected 
from growing trees, so that the determination of the species was 
certain. The trees were all about 15 years old, with the exception of 
the two cut at Berkeley, Cal. (shipment 17), which were about 30 
years old. The timber, therefore, contained a large amount of 
[Cir. 179] 
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