La Mesa Beautiful talked trees at annual meeting with San Diego County arborist

Members of La Mesa Beautiful could be called die-hard green thumbs for their commitment to attend the annual meeting last Sunday at the Nan Couts Cottage in spite of the pouring rain. The trees outside the cottage were bright green, soaking in all the moisture.

The members cozied up in the cottage to listen to a presentation by Robin Rivet, an arborist of San Diego County Trees.

Members of La Mesa Beautiful could be called die-hard green thumbs for their commitment to attend the annual meeting last Sunday at the Nan Couts Cottage in spite of the pouring rain. The trees outside the cottage were bright green, soaking in all the moisture.

The members cozied up in the cottage to listen to a presentation by Robin Rivet, an arborist of San Diego County Trees.

Rivet talked about why trees were important to the health of the city. “Everyone knows that trees give off oxygen. But do you know why that’s important? Both carbon and oxygen are building blocks of people and plants,” she said.

Rivet said that 100 trees remove 10 tons of carbon dioxide a year, 505 pounds of pollutants a year and 139 pounds of ozone per year.

“We have to start thinking about the oxygen that trees provide. Trees also keep the atmosphere cooler. They protect air quality. The leaves, branches and trunks strain the particles in the air,” she said.

However, in the past 30 years, there has been a loss of more than 600 million trees. In California, at least 70 percent original habitat has been destroyed.

This loss ends up hitting people’s wallets in energy costs. Rivet said that planting more trees could lower air conditioning bills by at least 50 percent. 

Pointing out the window, Rivet asked the members to consider another benefit of having trees in the urban landscape.

“Trees soak up rainwater. And that means less erosion,” she said.

Besides all the health and geographical benefits that trees provide, trees do a lot to complement business. “People will travel a longer distance to shop tree-lined streets,” Rivet said. “That’s why places like Grossmont Center do so well.”

In addition, well-tended trees add value to private residences, and areas with more trees have lower incidence of people with asthma. Recuperation time for patients in hospitals is lessened when there are plenty of trees to gaze upon. 

Yet another benefit of trees is that people have a tendency to more outside. Public housing projects that have trees have less crime, too.

“People gather around and under trees. That creates a more definite sense of community,” Rivet said.

The city of La Mesa is truly a jewel of the hills for trees because it is in what Rivet explained was a Sunset Zone. The microclimate is deal for growing all kinds of trees. 

“La Mesa is one of the best places in the United States to grow tropical fruit trees, including avocado,” Rivet said.

For the upcoming spring season in La Mesa, Rivet suggested planting apple, blueberry, cherry, nectarine and orange trees. 

“A lot of people are under the impression that trees are an added expense to maintain. But before you go for the chainsaw, do the math. Sidewalk repair is always less costly than pulling out trees.

Rivet challenged people to rethink the idea that trees drink too much water. “Trees save water. One hundred mature trees catch up to 6,000 gallons of water a year.

“I like to say that money really does grow on trees. It costs from $250 to $600 to plant a tree, including the first three years of maintenance. A single street tree turns over $90K in dollars of direct benefits. Trees pay residents back by saving $20K in energy costs,” Rivet said.

But before running off to the nursery to buy new trees, know the facts, Rivet suggested.

“Don’t get boxed trees. Of all the nurseries that I went to in San Diego, I only found two boxed trees that looked healthy enough to withstand a planting,” she said.

Rivet also suggested making the hole for the new tree three times wider than the tree. Neither is digging deep as important as originally thought. Rivet brought up an image of two Liquid Amber trees on her Power Point. Although the two trees were growing next to each other, one had bad roots exposed above the ground, while the other had a healthier look, with no roots showing.

The tree with the roots above ground had received too much surface water, while the healthier tree had not been over-watered.

“Once a tree has been planted and is still in good shape, there’s no reason to water the tree any closer than its canopy. In fact, water should never hit the trunk of a tree. You’re just teaching it to maintain its growth within a small area. 

“Don’t compost and amend the soil because you are telling the tree to stay small. So unless you want a bonsai style tree, leave it alone. It knows how to grow on its own,” she said.

With respect to how tree planting should be approached by the city of La Mesa, which has been named a Tree City USA, Rivet said that diversity in trees are important. 

“Just like a community, you want to mix ages and types of trees. We also have to be visionaries and think what it will all look like in 100 years,” Rivet said.

A round of applause went up for Rivet by the members as she finished. La Mesa Beautiful President Cindy Knox thanked Rivet for coming.

“And thank you to all the members. We look forward to a productive year. Don’t forget our plant sale on May 2,” Knox said.

Pam Crooks, a La Mesa resident, decided to become a member of La Mesa Beautiful that afternoon. 

“I’ve always wanted to and I enjoyed the talk today. If nothing else, I’ll know not to buy those boxed trees from the nursery,” said Crooks, who enjoys gardening at her home.

For more information about La Mesa Beautiful, go to www.lamesabeautiful.org.