American Lumber Popular, Says Oxholm, Back From Tropics

Wood construction methods as developed by engineers in the Panama Canal Zone are the mosf effiiieni of their kind, in the opinion of Axel H. Oxholm, Director of the National Committee on Wood Utilization of the Department of Commerce, who has just returned from a trip to Central America. If a knowledge of these methods and detailed information in regard to the uses for American woods could be spread to other tropical countrids, the market for American lumber would appreciably increase, he believes.

Mr. Oxholm visited the Canal Zone at the invitation of Governor Harry Burgess, who placed him in touch with department heads in the Canal Zone, and made it possible for him to gain a first hand knowledge of wood using practices in the zone. Before Mr. Oxholm's departure from Panama, a conference of all department heads and their assistants was called at the Governor's instigation for an exchange of views with these officials in regard to wood utilization problems. Both Army and Navy organizations located on the Isthmus were represented at this conference. The Canal is one of the largest users of American lumber, and it is hardly possible to find more diversified uses for wood in one locality than is found in the Canal Zone. 'tlt is remarkable" said Mr. Oxholm, "that wood is playing such an important part in building and construction in the Canal Zone, since climati'c conditions, insects, and wood borers seem to combine to destroy materials of organic origin, such as Wood. Little does the non-technical visitor to the Canal Zone suspect that behind the constru,ction of wooden houses, railway equipment, docks, and the many other wood construction operations, lie years of painstaking effort and experience in establishing the best methods of preventing the attack of these enemies of wood. Most residences are either all-wood structures, or partly wood and partly concrete. This latter type of construction seems to be preferred at the present time. For the administratlon buildings and .other structures of major importance in the Zone all-concrete construction is used.

"While in the United States wood destroying insects usually enter buildings by boring through the ground, in the Canal Zone and in many other tropical sections there are in addition the so-called flying ants which may enter through windows, doors, or other openings, and are therefore much harder to combat. The extreme humidity of the tropics also puts wood to a very severe test, and it is doubtful whether American lumber is used anywhere under more difficult service conditions than it is in the Canal Zone. And yet the fact that wood is so extensively used in building and construction, definitely shows that through engineering skill these enemies of wood have been controlled.

"California redwood, cypress, southern yellow pine, and Douglas fir are the principal woods used in the Canal Zone. They have been selected either on account of their natural resistance to decay or insect attack, or both. Interesting experiments are now being carried on by Canal Zone engi-neers in insulating wooden structures from the ground by using metal shields. In many cases chemicall-y treated lumber is employed with equally good results. As an interesting _example of economy in wobd uses it may be mentioned that railway ties in the Canal Zone, il untreited, only last two or three years, while creosoted ties have an average.life of fourteen or fifteen years; and the latter may be obtained at a relatively small increase in cost. Wa* and means of extending the use of treated lumber for gen- eral building purposes are now being studied. Califoinia redwood and cypress are bojh teririte-resistant woods. T.his also applies to softwoods of other species having a high percentage of pitch. Canal Zone eigineers are" in close touch with Mr. James Zetek, associatd entomologist of the U. S. Department of Agricul,ture who is in chaige 9f plant insect investigations ai Barro Colorado, C. Z. frr. Zetek and Dr. Thomas E. Snyder, entomologist at headquarters of the Department in Washington,-D. C., have done. outstanding work- in combating insect damage to wood and were it not for the findings of the Bureiu of Entomology Ameri.can lumber would not have attained the status it now has in the tropics."

The National Committee on Wood Utilization is now preparing a booklet on Wood Construction Methods in the Tropics, and Canal Zone ofricials have already pledsed their cooperation in this work. Since the panimi CJnal is the outstanding engineering accomplishment of the (Continued on page 44)

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