What to do with a landmark 60-inch DBH catalpa, standing on the property of an inn that is named for the tree? It has a long vertical crack that can be seen to open slightly in a high wind. Resistograph test at the base indicates slightly more than 40% strength loss. It leans east with a full healthy crown over the junction of a state and a county road, both lightly traveled. I know it ought to be removed, but it is a very important tree to owners and to town. Any way to preserve it 5 years while a new catalpa can be planted and begin to establish?

Reply to post by Bill Logan, on January 04, 2002 at 06:58:57:

If Resistograph measured 40% hollow, is that really the same as 40% strength loss? Probably not.
IMO the very first thing to do with a tree that has a visibly opening crack is to reduce that full healthy crown. Cutting out weight lessens strain on the defect. Correcting that lean over the road would be a priority. Keep interior growth that has a damping effect.
Crown reduction is not a well-understood technique, mainly because the strategy is determined more by the tree than by the trimmer.
Removing dead dying damaged diseased defective branches comes first. Then a fresh look is taken at the entire tree. Choosing branches to keep means reading which are the most vigorous ones which cause the least strain on the defect.
The guideline of removing only 25-33% of the foliage at a time is less important here than considering which branches will have foliage that is capturing the most sunlight that feeds the tree.
Managing undergound resources comes next. Healthy root function is needed to compartmentalize the decay, grow callus that will prevent the crack from worsening, and help new foliage grow.
Only after all this is done should the installation of hardware, which is invasive and causes wounds, be considered.
Before all this, of course, the owner should be notified that the tree has a hazardous defect, and that the steps taken to reduce that hazard can never eliminate it.
Planting a replacement tree(s?) is good, but how long the original lasts with a reasonable degree of safety can only be determined over the years. Bartlett's 20-point system works well. Measure and photograph the callus formation. Precisely measuring the trunk girth annually might be a good indicator. Videotape the tree's movement in wind.
If I was working on this tree, my goal would be to help it survive as long as I do. Removal is always the last option, else what's arboriculture for?