Dry conditions, but no chewing tobacco smell
By Richard Snell
What a difference a year makes. Last year at this time, we were still recovering from the effects of the December 2007 ice storm that hit the eastern two-thirds of Kansas, and on east and south of here. That included the chewing tobacco smell I encountered when I went outside every day.
"Chewing tobacco? What's he talking about?" you say. Well, it was all the broken limbed trees with their flowing sap that did it. I have wanted to write about this for a year now, and just never found the time.
It took me a while to figure it out. I would walk out of the house and my nose would pick up this foul odor that smelled like someone was chewing tobacco. Yes, like most old farm boys and baseball players, I "chewed and dipped" a few times, so I know that smell. We start the Walk Kansas program the first of March, so I really figured it out when I started walking in other neighborhoods and would encounter the same smell on certain trees.
In the total scheme of things, it didn't hurt anything but my nose. Most people pruned their broken limbs or had really torn up trees removed. I still have some hanging limbs that are too high up in the trees that I can't get to, and I can't afford to get a professional trimmer in to take them off. So, a couple of them hang by a thread as reminders.
What I was smelling was "slime-flux" or "wet wood disease." This is a common problem with some of our faster growing shade trees--elms, silver maples, mulberries, cottonwoods, poplars, and willows. It is due to a bacterial infection of the heartwood. The bacteria blocks the flow of water and nutrients in the trunk and a gas produced by the bacteria pushes the sap out through open wounds, pruning cuts or cracks in the bark. The sap is caustic and can kill grass it drips onto. It can cause stains on sidewalks and cars it may drip onto, from the yeasts, fungi, and other organisms outside the bark which cause the sap to ferment and develop a foul smell.
If we ever encounter it again, which I have no doubt we will, you can minimize the foul smell by swabbing the area where the sap seeps out with a 10 percent solution of chlorine bleach to kill the fermentation organisms. This will be a temporary solution to the problem and must be repeated as the odors redevelop.
The disease usually does not kill an otherwise healthy tree, but it does stress the tree. It may contribute to branch dieback and to the death of trees which are stressed by lack of water, winter injury or other injury. So, keep your trees watered during these dry times.
There is nothing you can do to cure the disease. An older recommendation is to "pipe" the trunk of infected trees by inserting a pipe through the bark of the tree. The intent of piping is to drain the gas pressure and the sap. Unfortunately, this procedure has proven to be more damaging than the slime-flux disease and is no longer recommended. You should take measures to keep the tree as vigorous as possible, so that it may continue to grow in spite of the disease. This means you should provide adequate irrigation when needed and in the zone of absorbing roots. Absorbing roots are found from just inside the drip-line of the tree outward to a distance from one to three or more times the height of the tree. The drip-line is the ring of soil under the outer edge of the tree's branches. When nutrient deficiencies are indicated by soil testing or by symptoms in the tree, needed nutrients should be applied in this same region of absorptive roots in which water is applied. Prune out dead or injured branches, being careful to leave the branch collar, a slightly swollen area at the base of the branch being removed. Leaving the branch collar promotes more rapid wound closure and limits entry of decay organisms into the remaining portion of the tree.
The sap oozing out can inhibit wound closure. Nevertheless, pruning paints are not needed. Since you are removing dead or severely injured branches, you can prune them any season of the year.
The ice storm a year ago started our wet trend for last year, following a very dry fall of 2007. We have now gone from wet to dry again. It may be dry and we do have a burning ban on in the county, but at least we don't have that smell.