Annals 
of the 
= Missouri Botanical Garden 
Vor. 4 | APRIL, 1917 №. 2 
STUDIES IN THE PHYSIOLOGY OF THE FUNGI 
ta Рнучосдт, Properties OF Woop ім RELATION то DEcAY 
INDUCED ву LENZITES SAEPIARIA FRIES 
SANFORD M. ZELLER 
Research Fellow in the Henry Shaw School of Botany of 
Washington University 
INTRODUCTION 
Much interest has been manifested among the lumbermen 
--ава those associated in allied industries concerning specifica- 
\ 
tions for structural timber. The classification of structural 
timber is based on strength and durability. Members of the 
Forest Service at the Forest Products Laboratory, Madison, 
Wisconsin, have shown that the true criterion of the strength 
of wood is its density (specific gravity), and that the 
рет” entage of summer wood indicates its density (Betts, 
"xe gj. But the physical properties of wood, which influence 
its durability, hitherto have presented an open question, and 
it is the purpose of this paper to report the investigations on 
this subject carried out by the author at the Graduate Lab- 
oratories of the Missouri Botanical Garden. 
The experiments were conducted with three species of yel- 
V pine, Pinus palustris, P. echinata, and P. Taeda. Special 
"attention was given to the physieal properties of each sample 
of wood used, data being secured on (1) resin content, (2) spe- 
cific gravity, (3) percentage of summer wood (the dark por- 
tion of the annual growth ring) or proportion of summer 
wood to spring wood in the growth rings, (4) the width of the 
growth rings or number of rings per inch measured on a 
a later paper the кет will discuss the literature оп the ана cule 
ED: structural timbers as they relate to strength, as well as the results of an experi 
mental study of the dee Б between strength and durability of rein pine 
tiniber 
ANN, Мо. Вот. GARD., Vor. 4, 1917 (93) 
