68 
WOODPECKERS IN RELATION TO TREES. 
THE WALNUTS AM) HICKORIES (juGLAXDACEjE). 
The trees of this family furnish the most costly woods produced 
in the United States. They are frequently attacked by sapsuckers 
and the resulting injuries are severe and often 
ruin the lumber, except for fuel or heavy con- 
struction. Serious defects have been observed 
in the wood of 12 of the 19 native species, and 
probably all of them are subject to sapsucker 
injury. In black (fig. 18) and in Texan wal- 
nut, the defects consist of heavy black stains 
nuining far along the grain and black checks, 
cither filled with loose plugs or open and 
knotty. They spoil the ornamental appear- 
ance of these woods. 
In hickory (PL X, figs. 2 to 4, and PL XI, 
fig. 1) the blemishes consist of open black 
checks (varying in size up to 2 by 4 inches), 
sometimes soft walled or partly filled with 
spongy growth, frequently connected with 
gnarly fissures up to 2 inches in length, which 
usually extend toward the bark. These are 
surrounded by brown or black stains called iron 
streaks, which penetrate more or less wood 
adjoining the wound and follow the grain some- 
times for many feet. They are serious in all the 
species examined. Mr. Carlos G. Bates of the 
'The hickory is oftentimes 
damaged beyond the effect of the streak. As the 
wound made by the bird heals over, a small lump 
is formed over the spot, and stimulated to hyper- 
trophied growth (by the lack of pressure where the 
bark has been removed). This in time becomes a 
sort of tubercle standing out at right angles to the 
stem and protruding through the bark. Sooner or 
later it ceases to grow, and the normal growth of 
Fig. 17.— Effects of sapsucker 
work on wood of Carolina 
poplar (l'npitlus ddtoides). 
Large chocks and gnarled 
grain. 
Forest Service says: 
the tree buries it. leaving 
i flaw in the wood equal 
to a huge. loose knot." 
The abundance and extensiveness of stains and 
gnarly growth in hickory unfit the wood for orna- 
mental purposes, and the fact thai the iron streaks 
make the wood harder to work and that check- 
ing takes place readily along them, spoils the 
wood for many of its most important uses. 
"The wood is heavy, hard, very strong, tough. 
FlO. IS.— Effects of sap- 
sucker work on wood 
oT black walnut (Jug- 
lins nigra). Holes and 
dark stains. (From 
Hopkins.) 
