El Niño no show dooms growing trees

Ask the Arborist


Dave Mortimer

Dave Mortimer

It seems now more than ever I get asked questions about trees that are dead, appear dead or are dying. It’s not surprising, I guess, considering the wet winter we almost had. El Niño sure was a bust, at least for those of us in Southern California.

Remember back in the middle of autumn when all those meteorologists on TV were telling us that 2016 was going to be a rain event for the record books?

In November they showed us all the warm water in the Pacific and told us to brace ourselves for the inevitable huge storms that were going to hammer us. In December, some really bright guy said he would stake his reputation on the fact that there would be flooding in SoCal by the time we watched the Super Bowl. Turned out to be a warm, sunny day.

I wish I could make the kind of money these “experts” get paid for guessing wrong more than they guess right. Anyhow, now we’re really in a bad situation.

Although the snowpack in the Sierras has returned and the coming thaw should help fill many reservoirs, the underground water level in local aquifers—which native trees depend on for survival— is approaching critical mass.

Trees that should be green now but aren’t are already in trouble. Trees that appear just fine now won’t make it through the summer.

If, for instance, you have a pine tree, any species—Aleppo, Monterey, Canary Island or stone pine—and it is yellow or brown, it’s likely dead and not coming back. If it usually is dark green but is instead light green, it may have a chance, but that usually means that the poor thing is on the way out.

We’ve talked a lot about alder trees because they’re a favorite of many landscapes. But I believe that within 10 years—probably sooner—the sight of an alder tree will be a rarity in this area. They just need too much water that we cannot give them. If you have an alder tree in your yard that is not full of lush, new green leaves, chances are that tree is not going to make it through the year.

Healthy valley oaks are looking really good this spring with lots of new foliage, but if you see one that is not leafed out by now it is probably dead. By the way, do not be afraid to water your oak trees right now. They need water just like any other tree, and you need to give them what nature has failed to do.

I suggest a good saturation to at least 18 inches in depth: Just keep the water application away from the base of the tree. Apply water in the area of the dripline.

Generally, if a tree doesn’t look good right now, it has problems. There are some exceptions. If you have a tipuana, a jacaranda or an albizia tree and it looks terrible right now, that is pretty normal.

These three species look barren through late spring, but they begin to look normal by early summer if they’re healthy. Tipuana trees are just looking terrible right now and are getting bare, but soon they’ll be full of yellow flowers followed by new leaves.

Many jacarandas are now blossoming and will get new leaves in June. Albizia trees do much the same but have very messy pink flowers before they look normal. With the exception of these few odd species, most trees should be looking good at this time of year.

Only time will tell how many trees we’ll lose this summer due to the drought. My advice: Water your trees now and apply mulch if you can to save what you can.

If you have questions about the health of specific trees, email me and send a picture if you can. Many people do; I enjoy the feedback.

David D. Mortimer is a certified arborist and tree risk assessor, has 40 years’ experience in the tree-care industry. Email him at dmortimer@roadrunner.com.


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