UNITED STATES DEPARTMENT OF AGRICULTURE 
1 BULLETIN No. 1037 
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Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief. 
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Washington, D. C. 
PROFESSIONAL PAPER 
August 19, 1922 
THE CONTROL OF SAP-STAIN, MOLD, AND INCIP- 
IENT DECAY IN GREEN WOOD, WITH SPECIAL 
REFERENCE TO VEHICLE STOCK. 1 
By Nathaniel O. Howard, Pathologist, Office of Investigations in Forest 
Pathology. 
(In cooperation with the Forest Products Laboratory of the United States Forest Serv- 
ice, Madison, Wis.) 
CONTENTS. 
Page. 
Introduction 1 
Sap-stain 3 
Other fungous organisms causing 
surface discolorations in green tim- 
ber 12 
Factors which favor the growth of 
sap-stain and mold fungi 14 
Page. 
Durability of stained or molded 
wood 17 
Losses due to sap-stain or mold 18 
Control measures 21 
Summary 50 
Literature cited 52 
INTRODUCTION. 
During periods of transit and storage, previous to its ultimate 
manufacture, green timber containing a high percentage of sapwood 
often suffers considerable damage. This is particularly true during 
the late spring and summer months when deterioration brought about 
mainly through a discoloration of the sapwood, known as sap-stain, 
sometimes necessitates degrading on a large scale. This staining 
of timber has occasioned severe losses in Europe as well as in the 
United States, and many expensive investigations have been made to 
determine the nature of the stain and to discover a satisfactory 
remedv. 
1 The writer wishes to acknowledge his indebtedness to Mr. C J. Humphrey, in charge 
of the Laboratory of Forest Pathology, Bureau of Plant Industry, in cooperation with 
the Forest Products Laboratory, Madison, Wis., for facilities and for advice in outlining 
the work ; to Dr. Charles Thorn and Miss Margaret B. Church, of the Bureau of Chem- 
istry, for the identification of mold fungi ; to Mr. H. D. Tiemann, physicist and specialist 
in kiln drying, Forest Products Laboratory, Madison, Wis., for the loan of photographs ; 
to Mr. Joseph Ashcroft, of Poplar Bluff, Mo., for cooperation in the experimental dipping 
of spokes ; and to all others who, by information, suggestion, or criticism, have con- 
tributed to the preparation of the manuscript of this bulletin. 
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