August, 1945 



Carter: Wetwood of Elms 



409 



Urbana in Champaign County ; Martins- 

 ville in Clark County; Mattoon in Coles 

 County; Barrington, Brookfield, Chica- 

 go, Des Plaines, Evanston, Glencoe, La 

 Grange, Northbrook, Oak Park, Park 

 Ridge, Techny and Western Springs in 

 L?ook County ; Timothy in Cumberland 

 County ; Clinton in De Witt County ; 

 Tuscola in Douglas County ; Addison, 

 Elmhurst, Glen Ellyn, Hinsdale, Lombard 

 ind Villa Park in Du Page County; Paris 

 ind Redmond in Edgar County ; \Villo\v 

 Hill in Jasper County; Aurora and St. 

 [^harles in Kane County; Lake Forest in 

 ^ake County ; Ottawa in La Salle County ; 

 Decatur in Macon County ; Bloomington 

 n McLean County; Hamlet in Mercer 

 County; Hillsboro in Montgomery Coun- 

 :y ; Peoria in Peoria County ; Danville in 

 ^'^ermilion County and Rockford in 

 iVinnebago County. Distribution of the 

 1-0 towns is shown in fig. 1. 



Trunk Pathology 



Wood Discoloration. — Wetwood in 

 ;lms is characterized by dark brown dis- 



coloration that may appear in current- 

 season trunk wood as streaks or broken 

 bands or in several annual rings as narrow 

 to broad streaks or broken bands, fig. 2. 

 The discoloration sometimes extends 

 beyond the current-season wood into the 

 cambial region and phloem, Hg. 3. There 

 it is grayish brown and appears as short 

 streaks or irregular, elongate patches. 

 Discolored wood appears water-soaked. 

 When it is cut, sap oozes out. 



Fig. 3. — Wetwood discoloration can some- 

 times be found in tiie cambial region and 

 phloem of elms, where it is grayish brown and 

 shows as short streaks or elongate patches. 



Fig. 4. — Fluxing through a wound made in 

 Fig. 2. — Section of elm trunk affected with the removal of a large branch. Toxicity of the 

 /etwood, showing discoloration of inner wood flux from wetwood-affected elm prevents cal- 

 nd brown streaks in current-season wood. lus formation at the base of the cut. 



