August, 1945 



Carter: Wetwood of Elms 



443 



in 1938 wood to 0.5 inch in 1942 wood. 

 It did not penetrate 1943 or 1937 and 

 older wood. However, 1943 wood was 

 blocked off by the screwed-in syringe. 



Penetration of malachite green was 

 most extensive in the two trees that had 

 their trunk bases submerged in dye for 

 3 hours. Both trees were about 18 feet 

 tall. The dye spread to the top of the 

 trunk and into some branches in the 1943 

 spring and early summer wood but only 

 9 feet up the trunk in the 1943 late sum- 

 mer wood. It spread upward 8 feet in 1942 

 wood, 7 feet in 1941 and 1940 wood, 6 

 feet in 1939 wood and 4 feet in 1938 late 

 summer wood. The dye did not penetrate 

 1937, 1936 or 1935 wood, or 1938 spring 

 and early summer wood. Evidently, the 

 1935—1937 wood had become inactive. 

 The 1943 or current-season wood, es- 

 pecially the spring and early summer 

 wood, was the most active in carrying the 

 dye to various parts of the tree. 



From the cut leader submerged in mala- 

 chite green for 3 hours, the dye spread 

 down the trunk 60 inches in 1943 spring 

 wood, 42 inches in 1942 and 1941 wood 

 and 36 inches in 1940 and 1939 wood; 

 1939 wood was the oldest in this portion 

 of the trunk. The dye spread into branch- 

 es through the 1943 spring and early 

 summer wood and reached the branch tips 

 and penetrated the leaf petioles. These 

 branches were within 4 feet of the cut 

 on the leader and measured 6 inches to 5 

 feet long. 



Penetration of malachite green in a 5- 

 vear-old branch, cut 30 inches from the 

 trunk and immersed for 3 hours, was 

 mainly in 1943 wood. The dye spread 

 from 22 to 24 inches back from the cut 

 in 1942-1939 wood. In 1943 wood, mainly 

 n the spring and early summer wood, it 

 ipread from the base of the immersed 

 branch down the trunk 1 foot and up the 

 :runk 6 feet. The dye, as it spread up the 

 crunk, was carried out into lateral branch- 

 es through the 1943 spring and early 

 •ummer wood. 



With all methods of injection except 

 :he hand syringe, the distances to which 

 Tialachite green penetrated were greatest 

 n current-season wood, especially that 

 ;0rmed in spring and early summer. The 

 jiye failed to penetrate heartwood, be- 

 :ause, as MacDougal, Overton & Smith 

 ^1929) found, the heartwood of certain 



Table 6. — Analysis of Hinsdale, Illinois, 

 parkway soil in which elms affected with wet- 

 wood were wilting. 



trees is under pneumatic, not hydrostatic, 

 pressure. The failure of the dye to pene- 

 trate heartwood suggests that when dex- 

 trose, nutrient broth plus dextrose, mer- 

 curic chloride, copper sulfate, silver 

 nitrate, 8-hydroxyquinolin sulfate and 

 Elget(jl were injected, as described for 

 an earlier experiment, they also failed to 

 penetrate heartwood and on that account 

 could have only temporary effect on fer- 

 mentation and development of pressure. 



Soil Tests. — One topsoil sample and 

 one subsoil sample were collected in 

 September, 1939, from each of four park- 

 way areas in Hinsdale where elms affected 

 with wetwood were wilting. These sam- 

 ples were tested for pH with a Youden 

 apparatus and for nitrates and phosphates 

 with an Urbana soil-testmg kit. The 

 analyses are shown in table 6. Only in the 

 peat soil area, sample 3, was the soil neu- 

 tral to acid, pH 6 to 7 ; both topsoils and 

 subsoils of the other areas were highly 

 alkaline, pH 8. In all samples, nitrates 

 and phosphates were medium to low. 

 Much of the parkway soil in Hinsdale, 

 like that of many other villages and cities, 

 contains considerable quantities of fill, 

 which includes clay, gravel and cinders 

 mixed with loam topsoil. This type of soil, 

 as shown by analyses, is not the most fav- 

 orable for vigorous tree growth, especially 

 since the optimum pH range for American 



