Answers to readers’ questions




 

 

I get lots of emails asking questions that don’t warrant an entire column. Here are a few of the most interesting I’ve received recently.

Do trees have heart attacks?

People have a heart and trees have heartwood.

So do trees have heart attacks? Not exactly.

Trees don’t have a pumping heart, but their heartwood does decay, causing eventual structural failure.

Both trees and people have vascular and respiratory systems, but the functionality is different.

A human being’s heart attack is caused by a blockage of one or more of the arteries that feed the heart muscle. The artery that supplies blood to the pumping side of the heart is called the “widow maker” because when it’s totally blocked it usually causes instant death, with a few exceptions (that I have a very personal experience with).

That term is also used in relation to trees. A large broken branch hanging in a tree is called a widow maker because if it falls and you are under it . . . well, you get the idea.

Decay in the heartwood of a tree is caused by one or more of many species of fungus that get into the tree through wounds, either natural, or man made. The species that most causes heart rot in oaks is ganoderma.

Can a tree be partially dead?

When any mammal dies, it’s just dead, period. Of course I’m only talking biologically, not spiritually.

But in the tree world many terms are used to describe the health of a tree or the lack of it. If a pine tree is totally brown, it’s dead, no doubt about it. If its needles are yellow, we can say it’s dying or almost dead.

I’ve also heard people say their tree “is partially dead,” “kind of dead” and so on. And in some cases, you can say that with a tree. I think you’d be pretty confused, though, if your doctor told you that you are “kind of” dead.

It’s accurate to say a tree can be partially dead because sometimes the entire top or a few branches are dead and devoid of any living tissue but the rest of the tree is green.

On trees that have latent buds, buds unseen just under the surface of the bark, a dead branch or top can be trimmed off back to living wood and the tree will recuperate and send out new shoots near that area.

If done properly, the tree may look acceptable in a few years.

But as we know, if your doctor trims off your finger or your arm—it’s not growing back.

It seems unfair that lizards can grow back their tails when they are pulled off, while people, who are much more advanced living organisms, can’t grow back a new arm.

I’m going to add that to my list of things to ask God about someday.

Will that stump grow back if I don’t remove it completely?

The answer here is yes and no: It depends on the tree. If the tree is a Monterey pine or Aleppo pine, then no, it can’t grow back. If it is a eucalyptus, pepper, poplar or a whole host of other trees, the answer is yes.

For example, if you have eucalyptus trees that were planted along a wall for privacy and they are now too tall to do the job, don’t remove them and replace them with new trees. Just cut them off about 3 or 4 feet above the ground and watch how fast they grow back.

That huge, vigorous root system will quickly regenerate new shoots that within in a year could be 6 feet tall, and there you go, privacy once again.

Many trees will do that. If you want to know about a specific species and what they will do, email me.

Will the Dodgers win the World Series?

Beats me. I’m an arborist. I’m just frustrated that I haven’t been able to watch the games on my DirecTV because Time Warner won’t let me. Bummer.

David D. Mortimer is a certified arborist and a certified tree risk assessor with 40 years’ experience in the treecare industry. Email questions and comments to dmortimer@roadrunner.com.


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