58 WOODPECKEBS IN RELATION TO TREES. 
The condition iii wood of various kimls resulting from the everywhere common 
work of the clasd of woodpecker- known as Bapsuckers in the bark of forest and 
cultivated trees lia< been the subject <>i" special interest to me for many years, and 
my work on foresl insects has oaturally offered a good opportunity for observations 
and the collecting of specimens. The material collected represents some 10 species 
of foresl trees of many genera and families and from widely differing sections of the 
country. 
It appear- that the object of the Bapsucker working in the hark of living trees la to 
seenre Loth liquid and solid food from the Bap, cambium, and Lasl, and not for the 
purpose of collecting insects, or at least not primarily for that purpose. The punc- 
ture- in the hark vary in size, form, and arrangement according to the species of tree 
and the character of the food furnished. In the pine, spruce, hemlock, juniper, and 
probably in all conifers, the desirable substance is furnished by the living bast tissue 
and cambium, while the wood yields resin instead of sap; therefore the birds have no 
occasion to puncture the outer wood ring and very rarely do so, whereas in maple, 
walnut, hickory, and such trees as furnish at certain times of the year a profuse flow 
of saccharine Bap from the sapwood the outer ring of wood i- generally punetured. 
In the former the wounds are usually broad, often connected, and arranged in longi- 
tudinal rows, 1 while in the latter they are narrow', funnel-shaped, rarely joining, and 
arranged in transverse rows. The method of healing of these wounds is quite variable, 
being influenced not only by the character of the wound but by the species or class 
of trees in which they occur. The resulting defective or ornamental conditions and 
subsequent annual layers of wood also vary in character and economic importance 
with different kinds of trees and commercial products. 
The way in which sapsucker pecks are healed and the character- 
istic blemishes and ornamental effects produced may best be under- 
stood by the detailed consideration of these effects in a tree in which 
they are well marked. For this purpose the sugar or hard maple 2 
(Acer saccharum) is selected, a favorite tree of the sapsuckers and 
one often seriously injured b} r them. The punctures sometimes 
penetrate only to the sapwood, but generally they pierce one or 
more annual rings. Whatever the character of the original wound, 
more or less staining, varying from light yellow to dark brown in 
color, takes place in its vicinity and sometimes extends several inches 
up ;iixl down the grain. The greater the injury to the sapwood the 
more extensive is the stain. When the sapsucker's drill extends 
only to the sapwood, distortion of the wood healing the wound is 
usually at a minimum. It can make excess growth only by bulging 
out into the hole in the bark. Upon the extent of this swelling 
depends the amount of abnormality in succeeding annual rings. 
Figure 9A of the excellent series furnished by Dr. Hopkins illus- 
trates this type of healing. Here the excess growth was small and 
would probably have been smoothly covered by the next annual 
Layer, though a second stain would have been produced owing to 
1 Probably the contour of the i»ark has much to do with die arrangement of punctures. Conifers often 
have very thick hark hut with longitudinal cracks where the wood can he more quickly readied. Ver 
ins of picks occur on deciduous trees also, especially upon those having Ion? ridges or strips of thick 
bark with furrows between 
Lmensofhard ma pi.' here discussed were collected at Morgan town. w. Va. I Hopkins v, and in 
Dlinol 
