90 UTILIZATION OF CALIFORNIA EUCALYPTS. 
shrinkage and about 15 per cent tangential. Consider that air-dry 
wood contains about 10 per cent moisture; since the shrinkage varies 
uniformly with the removal of moisture after the fiber-saturation point 
is passed, the change in volume when the amount of moisture is reduced 
from 30 or above to 10 per cent will be only two-thirds as much as when 
the moisture is reduced from 30 to 0 per cent. That is, with a total 
shrinkage of 21.8 per cent, the reduction in volume when blue gum 
is dried from a green to an air-dry condition would be about 14 per 
cent. The maximum shrinkage in volume in the 28 blue-gum tests 
was 34.6 per cent and the minimum 13.5 per cent. 
By way of comparison, eastern red oak, when dried from a green 
to an absolutely dry state, has an average shrinkage in volume of 
about 18 per cent—very little less than in the case of blue gum. For 
hickory, the data on shrinkage are very limited. Such tests as have 
been made indicate a shrinkage of from 20 to 30 per cent when the 
wood is dried from a green to an oven-dry condition. 
SEASONING. 
The seasoning of eucalyptus offers the most difficult and pressing 
problem in connection with extending the use of California-grown 
timber. In strength, hardness, and durability several species of 
California-grown eucalypts have shown themselves practically equal 
to certain of our native woods that are particularly useful on account 
of those very properties, but no satisfactory method of seasoning 
eucalyptus lumber grown in California has yet been worked out 
on a commercial basis. The warping of veneer material does not 
necessarily destroy its value, since it can be flattened by heavy pres- 
sure and held in position by glue. 
In Australia, as stated in “‘ Notes Regarding Timbers of Western 
Australia,’ * the practice is to strip and stack at the mills for at 
least twelve months all timber intended for such uses as joinery 
work, house building, and flooring. The custom of putting into 
almost immediate use freshly cut sleepers and bridge timbers and 
letting them season in the work is practiced to some extent, but is 
considered by Australian engineers as detrimental to the life of the 
timber. They recommend stacking structural material and allowing 
it to season before use. 
In “Notes on the Commercial Timbers of New South Wales,” by 
Mr. J. H. Maiden, it is stated that very few of the eucalypts will stand 
the severe test of being cut into flitches while fresh and full of moisture 
without warping and checking. Mr. Maiden states that good results 
may be obtained either by barking the tree and allowing it to die 
eradually before felling it, or by gradually drying the timber in the 
a Tssued in 1906 under authority of Hon. Newton J. Moore. 
(Cir. 179] 
