56 WOODPECKERS IN RELATION TO TREES. 



Horsford, B. Yellow-bellied Woodpecker. Forest and Stream, XX, 124, 1883. 

 Hough, R. B. Handbook of the Trees of the Northern States and Canada. Lowville, 



N. Y., 1907. Several photographs of trees show sapsucker work. 

 Hoy, P. R. Dendrocopus varius, Linn. Yellow-bellied Woodpecker. Notes on 



the Ornithology of Wisconsin. Trans. Wis. State Agric. Soc, II, 356, 1852. 

 Hoy, P. R. The Sapsucker. Trans. 111. State Hort. Soc, V, 730-735, [1861-1864] 



1865. 

 Jones, Lynds. Sphyrapicus varius (Linn.). Yellow-bellied Sapsucker. The Birds 



of Ohio. Ohio Acad. Sci. Special Papers, No. 6, pp. 113-114, 1903. 

 Kennard, F. H. January Occurrence of the Sapsucker in Brookline, Mass. Auk' 



XII, 301-302, 1895, 

 Merriam, C. Hart. Sphyrapicus varius. Yellow-bellied Woodpecker. Remarks 



on some of the Birds of Lewis County, northern New York. Bull. Nuttall Orn. 



Club, IV, 1-6, 1879. 

 Merrill, J. C. Sphyrapicus thyroideus. Notes on the Birds of Fort Klamath, Oregon. 



Auk, V, 255, 1888. 

 Moore, N. B. Observations on some Birds seen near Nassau, New Providence, in the 



Bahama Islands. Proc. Bost. Soc. Nat. Hist., XIX, 245, 1878. 

 Morris, C. H. Winter Notes on the Yellow-bellied Sapsucker (Sphyrapicus varius). 



Wilson Bull. XII, 56-57, 1905. 

 Purdy, J. B. The Red-headed and other Woodpeckers in Michigan in winter. Auk, 



XVII, 174, 1900. 

 Thompson, Charles S. The Woodpeckers of the Upper Salinas Valley. Condor, 



II, 52-55, 1900. 

 Thompson, J. M. The Sapsucker. Appleton's Journal, VIII, 631, 1872. 

 Todd, W. E. Clyde. Sphyrapicus varius. The Birds of Erie and Presque Isle, Erie 



County, Pennsylvania. Annals Carnegie Museum, II, 559, 1904. 

 Warren, B. H. Sphyrapicus varius. Yellow-bellied Sapsucker. Report on the 



Birds of Pennsylvania. Ed. 2, pp. 168-170, 1890. 

 Weed, C. M., and Dearborn, Ned. The Yellow-bellied Woodpecker <>r true Sap- 

 sucker. Birds in their Relations to Man. Pp. 189-191, 1903. 

 Wright, M. 0. Yellow-bellied Sapsucker: Sphyrapicus varius. Birdcraft, pp. 



198-199, 1897. 



EFFECTS OF SAPSUCKER WORK ON LUMBER AND FINISHED 

 WOOD PRODUCTS. 



INTRODUCTION. 



Those relations of sapsuckers to trees which are detrimental to 

 man's interest are by no means confined to the external disfiguration, 

 the weakening, or killing of trees. Indeed in the aggregate sap- 

 suckers inflict much greater financial loss by rendering defective the 

 wood of the far larger number of trees which they work upon mod- 

 erately but do not kill. Blemishes, reducing the value, appear in 

 the lumber from such trees and in the various articles into which it 

 is manufactured. 



These defects consist of distortion of the grain, formation of 

 knotty growths and cavities in the wood, extensive staining, fat 

 streaks, resin deposits, and other blemishes. All of them result from 

 injuries to the cambium, their variety being due to differences in 

 the healing. Besides blemishes, ornamental effects are sometimes 



