Like all good things, trees need to be nurtured and maintained. And for many Southern Californians, a not uncommon sight of maintenance we've seen takes the dramatic form of trees having their canopies and branches cut off. It's a technique called "topping."
Why it matters: Rachel Malarich, L.A.'s forest officer, said she's seen topping proliferated in the region, which makes cooling down the city difficult. "It really makes it hard for us to meet our canopy goals as a city, because when we're trimming trees this way, it reduces the shade provided by those trees."
Why Angelenos need to pitch in: L.A. city crews, which service trees in public parks and between curbs and sidewalks, don't engage in topping. But with 80% to 90% of the city's overall canopy on private property, Angelenos have an important part to play in preserving these natural covers.
Here's an unassailable fact: Trees are awesome. Among the laundry list of benefits, they provide shade in our increasingly warming weather, they clean the air, prevent soil erosion, reduce noise pollution.
Which is why a rise here in Southern California of a practice known as "topping" is worrying arborists and others. You've probably noticed it: Trees having their canopies and branches cut off. The result (see photo above) is dramatic.
"This is sadly a very common practice.... I should say malpractice, honestly," said Bryan Vejar, a senior arborist at the environmental organization TreePeople. "Once you notice it and start to understand the hazards and harms of 'topping,' you'll see it everywhere."
Rachel Malarich, L.A.'s forest officer, said topping has indeed become more pervasive.
"I have seen the proliferation of tree topping across our region over the past decade or so," she said. "When I see trees that are cut that way, it is a little gut wrenching."
Why less is more when it comes to trimming
The practice of topping is hard to kick partly because of simple economy, said Vejar, explaining that people paying for tree trimming equate value with volume.
"So if I took out 90 or 100% of the volume out of the tree, you would think, 'Oh wow, what a good value I got," he said.
He added that people also mistakenly think that the more you chop off, the longer it'll take for it to grow back. In reality, he said "less is more with trees," meaning taking more care with what is trimmed can prolong the life and health of a tree, and make rapid growth less likely. That's because a lot of pruning can lead to what he calls "sort of a vicious cycle of regrowth."
Why topping = rapid regrowth
The rapid regrowth happens because topping triggers a panic response and sends the tree into overdrive.
"When you top a tree, the physiological response from the tree is to produce a lot of what are called water sprouts," Vejar said.
Those are all the long, thin branches that shoot out from a tree around its stumps.
"When you remove its photosynthetic array, all of its leaves and canopy, you're robbing the tree of its ability to feed itself," Vejar said. "It needs to put out some growth in order to shade the tree and also produce enough photosynthesis to keep the system running."
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LAist
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These branches are weaker and more at risk of breaking and falling. Big cuts also make trees prone to pest and diseases.
A topped tree with water sprouts.
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Fiona Ng
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LAist
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"That big surface area of the cut is basically a Petri dish for disease. And if there's any exposed heartwood, that is the central wood in the middle of the wood, then that is a prime real estate for wood decay organisms to start infesting the tree and killing the tree," he said.
Malarich, who manages the city of L.A.'s urban forest, said topping also makes it difficult to cool the city down.
"It really makes it hard for us to meet our canopy goals as a city, because when we're trimming trees this way, it reduces the shade provided by those trees," she said.
Malarich added that city crews, which service trees in public parks and those planted between curbs and sidewalks, don't engage in topping. But she said with 80% to 90% of the city's overall canopy on private property, Angelenos have an important part to play in preserving these natural covers.
"The goal should be to take as little as possible off the tree," she said.
When topping makes sense
There are circumstances where topping a tree could make sense, Vejar said, like if there's a fast-growing tree under the power line. Or, if a tree is dying.
"You want to retain this tree for as long as possible, but you also want to make sure that the limbs that do fail don't fall on your house or on your car or on your property," he said.
All is not lost, even if you have topped a tree. With time, patience and the help of an arborist in a process called "restorative pruning," the stronger new branches are nurtured to help the tree regain its health.
"It takes years to build a house and only a few moments of carelessness to burn it down, right? Well, it's sort of the same with trees," Vejar said.
Pro-tips on tree maintenance
Think through where you are going to plant a tree. "You don't want to, you know, put a tall, fast growing tree underneath the power line because eventually it's going to become in conflict and you're going to have to top it," Vejar said.
Try to trim back a tree during cooler months. "It's very stressful for the tree to be trimmed in the summer," Malarich said.
Get multiple bids.
Talk to your arborist and ask questions before deciding. "They should be able to tell you why they're removing certain portions of the tree," Malarich said.
After all, the better we treat these majestic organisms, the better they will treat us. "They're good for us mentally, psychologically and socially," said Vejar, who urges everyone to be realistic when making decisions about trees.
Everybody, he said, wants a big tree that grows fast, but also one that's low maintenance, drought tolerant, disease resistant and with no invasive roots — all while holding its shape over time.
