Q: A Thousand Oaks homeowner writes that a large eucalyptus tree in her neighbor’s yard was radically topped and trimmed, leaving no leaves on the tree. New leaves started to grow back but then died off. Now the tree looks dead. Is the tree dangerous?

A: Having been provided the location of this tree, I decided to go look at it for myself. I drove by and looked at the tree, and it is most definitely dead. This is a good example of why trees should not be topped as a means of trimming them.

As if it wasn’t bad enough that the tree was topped down 25 feet, the trimmers also cut off every leaf on the tree. It’s almost as if their sole motive for trimming the tree was to kill it.

I guess I will just never understand why some guys will climb a tree, butcher it and think it’s good. They either don’t know any better or don’t care. This is the most obvious downside of hiring a tree trimmer who is not a certified arborist. The work they perform is not worth the money or effort and usually ends with a dead, dangerous or unhealthy tree.

Quite often, though, even a butchered tree can sprout new leaves if the tree is otherwise healthy. For many years now, some species of eucalyptus trees in both Los Angeles and Ventura counties as well as in other outlying areas have been attacked by an insect called lerp psyllid. The way in which the insect kills the trees is by sucking the sap out of the leaves, causing them to prematurely fall off by the thousands. This creates an artificial defoliation of the trees in the summer months when they most need leaves to make food.

If the tree is otherwise healthy and getting ample water, it can usually send out new replacement leaves very quickly and therefore survive the insect attack. If, however, it has been under attack for several years and not getting all the water necessary for leaf replacement, the tree usually does not survive. Perfect examples of this are the hundreds of dead eucalyptus trees right next to the Ventura Freeway in the San Fernando Valley that have been dying for years.

I suspect that the eucalyptus tree in question simply did not have the available reserves to grow and maintain new leaves. When the tree trimmers cut off all of the leaves the tree simply did not have the ability to survive the shock.

Many species of eucalyptus trees have very brittle wood and shed branches easily even when they are alive and apparently healthy. Because of this, I never recommend that a large eucalyptus tree be allowed to grow over homes or areas of high pedestrian traffic.

Compared to many other species of trees in our area, it is my experience that large eucalyptus trees drop more live and dead branches than all other species combined. This eucalyptus tree, what is left of it, should be considered hazardous and removed as soon as possible.

David D. Mortimer is a certi fied arborist with more than 30 years’ experience in the tree care industry. E-mail questions to dmortimer@theacorn.com.