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Eucalyptus Lumber 



Abstract of Beport hy H. D. liemann, Forest Products Laboratory, 

 Madison, Wis., U. S. Forest Service, Department of Agriculture. 



PART I 



The object of this publication is not to discourage the planting 

 of eucalyptus, but to place such projects upon a sound rather than a 

 fictitious basis, and to show that other species than blue gum are 

 more suitable for many purposes, particularly for saw timber. So 

 much has been published about the fabulous values of this genus of 

 trees for hardwood lumber, founded solely upon fictitious and pros- 

 pective properties, that many people have been led to invest in plant- 

 ing these trees in the belief that marvelous returns would be realized 

 in the form of hardwood lumber equal in quality to hickory or oak 

 in ten, fifteen, or twenty years' 

 time. When all of these delusions 

 have been cleared away, as ulti- 

 mately must occur, there is dan- 

 ger of a reaction which will put 

 an end to all future planting. 



A clear annunciation of the 

 real facts, so far as known, is 

 earnestly called for by present 

 and prospective investors. If the 

 planting of this tree in California 

 is to continue in the future, and 

 it is of great importance to the 

 state that its importance should 

 not be brought to a standstill, 

 the operations must proceed on a 

 legitimate and not upon an in- 

 flated basis. The following arti- 

 cle has been written to give the 

 facts as far as they are at present 

 known. The conclusion of our re- 

 search and experiments is that the 

 blue gum is not suitable for lum- 

 ber until it has passed an age of 

 at least from forty to fifty years, 

 and a diameter of three feet or 

 more. Even so, it is much in- 

 ferior to many other species of 

 eucalyptus of slower growth, 

 many of which do not thrive in 

 California, but one and possibly 

 two appear to be suitable for 

 planting in this state. The state- 

 ment does not imply that small, 

 selected pieces of wood may not 

 be obtained from smaller trees, 

 even of the blue gum, but the 

 proportion is too small and the 

 waste too great to make the young 

 trees profitable for lumber. This 



fact is fully realized even in Australia, where no trees under two or 

 two and a half feet in diameter, even of the best species, as jarrah 

 (Eiicalyptiis marginata) and tooart (Eucalptus gomphncephala) , are 

 considered fit for the saw. The heart of even the largest trees is 

 conceded to shrink, warp, and check badly, and is always discarded. 

 No tree under thirty years of age is used, and generally the ages 

 range from fifty to two hundred years, and older. 



In considering the utilization of eucalyptus for lumber, certain facts 

 will be conceded to start with. First, the wood must be thoroughly 

 dry before it is of any value; second, it must be free from checks 

 or honey-combing; and, third, it must not warp, shrink, or swell un- 

 duly with atmospheric changes, if it is to be of good quality. Can 

 eucalyptus fulfill these requirements? 



That the wood of most species of eucalyptus, including blue gum, 



—20— 



BLUE GUM GROVE ABOVE BERKELEY BY THE DRY KILN. THE 

 TREES IN THE I'ICTUUE ARE BETWEEN 1 AND 1 »-!, FEET IN 

 DIAMETER AND AVERAGE 110 FEET HIGH. APPROXIMATELY 33 

 YEARS OLD. SOME TREES ARE 135 FEET HIGH. 



is very hard, very strong, of a beautiful appearance, and susceptible 

 of a good polish, there is no question. In fact, it is apt to be too 

 hard, making it difficult to work. The problem then of the utiliza- 

 tion of California eucalyptus for lumber is simplified to whether 

 it can be successfully dried without cheeking or warping, and 

 whether it will keep its shape after it is dry. 



For the purpose of determining these questions, the Forest Service 

 began a research in 1911 al Berkeley, Cal., where a small dry kiln 

 was erected by F. C. Havens, in co-operation with the Forest Service. 



The kiln was built according to a 

 special design invented by H. D. 

 Tiemann of the Forest Products 

 Laboratory. Humidity and air 

 circulation are controlled by 

 sprays of water. The species 

 dried was chiefly blue gum (Euca- 

 hiptus globulus), from a grove in 

 North Berkeley near the kiln, 

 and a grove in Piedmont and one 

 large tree from the roadside 

 three or four miles east of Pied- 

 mont. Other species were also 

 dried, from various parts of the 

 state, including red mahogany 

 and sugar gum from the experi- 

 ment station at Santa Monica, 

 and some "San Jose" blue gum. 

 Little need be said here re- 

 garding the growing of eucalyp- 

 tus in California, as there is ex- 

 tensive literature already on the 

 subject ; but there is practically 

 no authentic information in re- 

 gard to the lumber produced by 

 these trees. 



Unfortunately, the species has 

 boon unduly exploited on the 

 Imsis of the lumber which it 

 should produce in an incredibly 

 short time. The fallacy in the 

 argument is plain, but it has 

 been frequently overlooked in the 

 glare of the imaginary future 

 prospects. Dry eucalyptus lum- 

 ber of excellent quality can be 

 obtained, especially that from the 

 older trees of Australia, and from 

 species other than blue gum ; and 

 it is used commercially to a large 

 extent. For many purposes it is equal to American white oak ; and 

 for some purposes, when a very hard wood is required, such Australian 

 species as jarrah, karri, tooart, and red mahogany, no .doubt excel in 

 valuable qualities. 



The eucalyptus heretofore planted in California has been mostly 

 the blue gum. It forms splendid looking timber trees in a marvel- 

 ously short time, which in fifteen years, if superficially measured 

 for volume or board feet, will scale an incredibly large figure, equal 

 to any other hardwood of fifty or seventy-five years of age. 



But here is just where the fallacy comes in. To what does the 

 scale apply in measuring the contents of these young trees? Is it 

 lumber, such as can be procured from the old mature trees grown in 

 their native habitat? Or, is it something different? Something 

 which is only near-lumber? Is it logical to apply to young trees the 



