Washington, D. C. August, 1924 
EFFECT OF KILN DRYING, STEAMING, AND AIR SEASONING ON CERTAIN 
FUNGI IN WOOD." 
By Ernest BE. Huszrt, Assistant Pathologist, Office of Investigations in Forest 
Pathology, Bureau of Plant Industry. 
[In Cooperation with the Forest Products Laboratory of the Forest Service. ] 
CONTENTS. 
Page. Page 
Entreduetion) 55. terete se eer 1 | Brief summary of the test muns____ 10 
ESE Giyl OUESS OW Ol ee es Be ee et ES 2 | Air-seasonming experiments _________ 14 
Material used in this study___-___~-~ 3 | Revival of fungi in wood after air 
Methods. of studyi2 se ee 5 Gy ie ier eer ve ere rye DE 15 
Silt mMernod's —— SS a ee 5. | Review of the results _-___________ 17 
Kiln-drying and steaming experi- Suleman yet ess Seb east We ee +9 
TAGE Ss ae a es ee eee es GJ literature, cited 221% 2. 2 oases 20 
INTRODUCTION. 
Among lumbermen and kiln-drying experts the belief is general 
that the temperatures and humidities used in the various commercial 
kiln runs and steaming processes, with the exception of stock that 
requires low temperatures and high humidities, are efficient in killing 
the various stain and decay producing fungi found in lumber and 
other wood products. Accurate tests to support this belief have 
never been made. It was the object of this study to determine 
whether the fungi in lumber are killed under ordinary commercial 
kiln conditions and steaming processes and to gain some idea of the 
minimum time and temperature limits necessary to kill these organ- 
isms. Such information has a wide application in the steaming 
processes commonly applied to gum, poplar, and other hardwoods 
previous to air seasoning and to the steaming of billets in the cooper- 
age and other industries. It also has a very important bearing 
upon the sterilization of ties, posts, and poles and of mine, bridge, 
and building timbers when treated by a preservative process where 
i1This manuscript was submitted for publication December 24, 1923. 
Acknowledgments are due to Miss A. M. Waterman for aid in culturing some of the test 
blocks; to members of the section of timber physics, Forest Products Laboratory, for aid 
and advice in handling the dry kilns; and to Dr. C. J. Humphrey for advice in outlining 
the project and furnishing samples of infected wood. 
91940°—24——_-1 
