My orange tree is about 15 years old, just over 3′ high, and thriving on my downtown Toronto roof terrace. After a hugh flush of flowers earlier this year it is loaded with small oranges. Today I discovered that an animal (squirrels are common on my terrace) has removed the bark from the soil line up about 10″ to where the first branching occurs.
Bark from the first 4 inches is removed completely around the trunk, then the bark removal is about half of the trunk surface. for the rest of the 10″ or so.
What should I do to remedy the damage, if that is possible? Of course I need to deter the animals but for right now my concern is to try to prevent any insect or other infestation.
Thank you for writing. This is a very interesting, albeit unfortunate, issue, that might be of interest to many other gardeners sharing their urban plant life with squirrels.
It sounds like your citrus tree may be a dwarf variety, considering its age, but modest height. First, without an image, it is not possible to verify if the damage is actually the result an animal chewing, unless, of course, you’ve caught a squirrel in the act. If it hadn’t been that your tree is on a roof-top terrace, rabbit damage would have been a first thought. However, squirrels are known for their habit of chewing on a wide variety of things, including tree bark, which they typically collect for nesting. They are also known to tackle bark when other food is scarce, and, particularly during summer drought-y spells, when water is at a premium.
There is another possibility: Psorosis bark scaling is a virus, causing patches of scaling, or peeling bark, on the trunk and branches. It is most common in older trees. But this generally affects both the trunk and the branches, which you haven’t reported damage on.
The good news: you say your tree is thriving and bearing plenty of fruit, which indicates the plant, and its root system, is generally robust, and hence likely more capable of surviving this damage. To prevent further loss of bark, protect the entire height of the trunk with a section of flexible, plastic, tree wrap, slotted to allow air flow, to mitigate bark rot. When bark is removed from trees, the cambium layer of sugars and nutrients is exposed. When wounded, the cambrium begins to grow a new protective wall, as a barrier against decay in new tissues: called compartmentalization.
Regarding your concern to prevent insect or other infestation, the cells of this barrier zone are thick-walled and contain chemicals that are toxic to possible decay organisms. Wound dressing is generally considered to be of no help, and can sometimes harbour harmful organisms. And, an alternative: you might want to take the tree indoors, where it presumably winters, for a brief respite from further bark damage — and to let the fruit safely ripen.
Best of luck with your damage control.
P.S. Anecdotally, many gardeners report they are now providing water for the squirrels, to distract them from damaging fruit and vegetables, as they search for fluids.