132 College of Forestry 
chestnut (Castanea dentata), beech (Fagus atropunicea), 
white oak (Quercus alba), live oak (Quercus virginiana), red 
oak (Quercus rubra), scarlet oak (Quercus coccinea), yellow 
oak (Quercus velutina), pin oak (Quercus palustris), black 
jack oak (Quercus marilandica), willow oak (Quercus phel- 
los), tulip-tree (Liriodendron tulipifera), sassafras (Sassa- 
fras sassafras), red gum (Liquidambar styraciflua), wild 
plum (Prunus americana), wild red cherry (Prunus penn- 
sylvamca), black cherry (Prunus serotina), red maple (Acer 
rubrum), and striped maple (Acer pennsylvanicum). 
SUMMARY OF THE PuHysicaL AND CHEMICAL CHANGES IN 
Decayrep Woop. 
Macroscopic Characters.— Cross sections of trunks of the 
four dicotyledonous woods studied here in full detail, as well 
as many of the other dicotyledonous woods studied only 
macroscopically, exhibit a number of conspicuous, irregular 
zones of black wood. ‘These black zones are present invari- 
ably in the early stages of the decay of most dicotyledonous 
woods and often are prominent features of the decomposi- 
tion. No such black zones, however, were present in decaying 
hemlock wood. A more detailed discussion of these black 
zones, in which their origin, physiologic significance, and 
chemical relationships will be considered, will later be taken 
up under the heading “ The Metabolic Products of Polyporus 
pargamenus.” 
The decays of the five woods of widely different structure 
selected for study here, all agree in their sahent features. 
The first evidence of incipient decay is in the appearance of 
small, irregular areas in which the tissues have lost their 
natural color and appear as though bleached. ‘These lighter 
areas are destined to become individual centers from each 
of which the decay spreads in all directions. The decay is 
at first localized or confined to these innumerable centers in 
which the destruction of the woody elements becomes com- 
pleted before the decay spreads farther. As a result of the 
peculiar manner in which the decay acts the wood is decayed 
