I've got two black cottonwood trees that have four foot long decay columns in the main trunk of the trees within five feet of the ground. Decay seems to be elliptical wounds oriented longitudinally. Some epicormic new growth nearby on the trunk has these knobby shaped 1/2 inch diameter cankers around the stems. No construction, no signs of obvious wounding. Research in Sinclair Lyon and Johnson and several other sources hasn't yielded anything that seems to fit the situation (at least from the descriptions given). Anybody have any ideas?

Reply to post by Nathaniel Sperry, on April 04, 2000 at 01:38:37:

The knobby growths are probably unrelated to the decay. From your description, I suspect it may be a crown gall infection. Check Sinclair under 'bacteria'.

Reply to post by Nathaniel Sperry, on April 04, 2000 at 01:38:37:

Where in the world do you live? What elevation, winter temps, drought, etc.?
How big/old are these trees, and when did you first notice the decay?
The Silvics manual relates bacterial canker as a problem esp. in Europe.
The tree is also subject to frost cracks, which may be the initial entry point for fungus or bacteria.
Are the cracks on the south or southwest sides of the trees?