A few weeks ago, while taking a lunch break from writing on our back patio, I discovered that our poor persimmon tree had suffered massive limb trauma. I’m not sure what caused the damage, but as you can see in the picture to the left, it was severe. More than half the crown of the tree is lying on the ground to the left of the trunk. Some quick online research suggested that a tree with this much crown loss would be considered a lost cause by most tree surgeons. That’s a real shame, since this tree was a prodigious fruit producer last season, and it’s probably only about 5 years old. (I’m guessing on this front, since we started renting this place a little over a year ago.)
Now I’m not a huge fan of persimmons. I actually had never seen one before we moved to San Jose, and wasn’t prepared to handle the bushels of fruit we harvested from this one tree last year. In fact, we nipped 2/3 of the buds from the tree this spring to decrease the fruit production to more manageable levels.
That being said, I’m a big fan of trees, and hate to see one cut down in it’s prime. I decided to try to save the tree, and avoid both the hassle to me and the cost to the homeowner of bringing in a tree removal service. Online recommendations were mixed, but some folks reported success using glue to repair split trunk storm damage. Since our persimmon tree had suffered a major split but still had plenty of healthy bark that might close around the injury, it seemed worthwhile to give it a shot.
My first step was to prune the heck out of the fallen limb. The limb had split because it couldn’t support it’s own weight. Much of that weight was from fruit, all of which I removed. Some of it was from overextended limb and dense shoot growth. I cut as much of it off as I could, while trying to maintain enough green leaves to support that side of the tree through the rest of the summer. If the tree lives until the fall, I’ll prune the left side back even further for the winter dormant season. But for now, the tree needs as many leaves as possible to feed itself. Notice the dog house emerging from beneath the now pruned branch in the picture to the left.
My next step was to coat the inside of the split liberally with an indoor/outdoor wood glue that would help hold restore the joint’s structural integrity. Note that I didn’t go look for a wood sealant compound. These tar-like sealants used to be the industry standard for protecting tree wounds from critters, but they’ve evidently fallen out of vogue. I used the wood glue I had in my workshop, with the goal of repairing the joint, not sealing it up.
Anyone who has worked with wood glue before knows that it needs support and pressure while it cures. Once cured properly, wood glue joints are often stronger than the wood surrounding them. If you subject a repaired joint to the same stresses that damaged it in the first place, you shouldn’t be surprised to see a second crack tear through the wood parallel but offset from the original failure. I knew I had to support this joint during the glue curing stage and beyond if the tree is ever going to recover. The braces to the left are meant to be temporary. I’ll remove them next spring if all goes well. The tension wires to the right, however, are not temporary. They’ll be with the tree for the rest of its life, however long that turns out to be.
Call it my tendency to over-engineer, but I wasn’t satisfied with a belt and suspenders approach. I wasn’t too thrilled about the small diameter branches I used for the permanent cable supports. I wanted another permanent support that would clamp the split together and prevent formation of a secondary crack in the years ahead. Call it a belt, suspenders, and garters approach, for lack of a better term. So I drilled two pilot holes through the center of the limb, added some carriage bolts, nuts, neoprene cushions and washers, and voila.
The finished result? Three weeks later the damaged tree limb is back in place, and the glue is as cured as it’s likely to get. The bark closed up around the injury when I tightened the support bolts and hasn’t shown signs of cracking or falling off. There hasn’t been any severe leaf drop that would indicate the limb is dying, but it’s too soon to know whether I saved the tree. That may take a year or more. In the mean time, the tree looks a lot better than it did before I performed the emergency surgery. The whole operation cost me $35, most of which was for the bypass cutters I used to prune the branches from the fallen limbs. If I ignore the cost of the tools I’ll be able to re-use, the total cost was less than $10. It would have cost an order of magnitude more to have a tree removal service come in, and then I’d have a nothing but a hole in the ground where our cute little tree once stood. I think it looks better this way, bandages and all, don’t you?