Nov. xo, 1913 
Heart-Rots of Hardwood Trees 
117 
living trees of this species, as in the white oak, the rot may vary 
somewhat. 
In the chinquapin the fungus first delignifies the latest formed summer- 
wood fibers, those immediately adjacent to the large vessels, and spreads 
finally to all the wood fibers lying between the spring wood of any two 
successive. years. As the summer wood is composed largely of wood 
fibers, the ultimate result is an almost complete separation of the layers 
of spring wood. The concentric layers of the spring wood are separated 
at first by the white to yellowish white, cellulose fibers. Tater this cellu¬ 
lose is entirely absorbed, leaving only the concentric layers of the spring 
wood loosely held together by the remnants of the wood fibers and the 
few small vessels found in the summer wood (PI. VII, figs. 4, a, and 4, b). 
The vessels and other cells of the spring wood have in the meantime 
become more or less corroded and have assumed a reddish brown color. 
In the final stage of the rot the wood when dry is brittle and can be 
easily broken between the fingers. In old, weathered chinquapin logs 
attacked by this fungus the rot is very characteristic, consisting of con¬ 
centric layers of rotten wood which are so loosely held together that 
one can easily pull off layer after layer. 
A Pocketed or Piped Rot in Chestnut 
The material examined for the following description of the pocketed 
rot was obtained from the diseased wood of living chestnut trees (Castanea 
dentata) located near New Berlin, N. Y. In the hollow butts of these 
trees the resupinate form of Polyporus pilotae was found. Some trees 
were examined which had recently been made into railroad ties. Ample 
opportunity was thus given for a thorough study of the various stages 
of the rot in different regions of the tree trunks. 
The first indication of the rot is a watery brownish discoloration of the 
heartwood. In cross section this discolored area or “ soak” often appears 
as a central circular patch (PI. VII, fig. 5), often flanked by one or more 
very narrow crescent-shaped discolored areas, lying between the diseased 
portion and the sap wood, or sometimes the “soak” maybe eccentrically 
placed in the heartwood of the tree. These rings of diseased wood follow 
very closely certain annual rings and usually appear first in the immediate 
vicinity of the large spring vessels. Sometimes only one annual ring 
will show the disease, and this may extend for several feet longitudinally 
in the tree beyond that portion of the rot where delignification is evident. 
The mycelium of the fungus travels much more rapidly longitudinally 
in the tree than radially. It is first seen in the large spring vessels. The 
adjacent wood fibers soon show signs of delignification, which usually 
occurs most abundantly in the latest formed summer wood, where small, 
irregular, oval patches of cellulose are produced. These patches usually 
lie opposite the largest vessels and immediately adjacent to them. This 
association of cellulose and large vessels is especially noticeable in cross 
