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UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 1128 



Washington, D. C. PROFESSIONAL PAPER February 20, 1923 



DECAYS AND DISCOLORATIONS IN 

 AIRPLANE WOODS 



By 



J. S. BOYCE, Pathologist 



Office of Investigations in Forest Pathology 



Bureau of Plant Industry 



CONTENTS 



Page 



Introduction 1 



General Considerations 2 



Woods Used for Airplane Construction 3 



General Defects of Airplane Woods . . 5 



Color Comparisons 14 



Discolorations Caused by Wounds . . 17 



Lightning Wounds 17 



Sapsucker Wounds 20 



Pith-Ray Flecks 20 



Page 



Chemical Discolorations 23 



Discolorations Caused by Fungi .... 24 



Sap-Stain 25 



Brown-Oak Discolorations .... 29 



Decay Discolorations 30 



Decay in Finished Airplanes 40 



Summary 42 



Literature Cited 45 



Defects of Wood Referred to in This 



Bulletin, Arranged by Species .... 60 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1923 



