5 Tips to Preserve Our City of Trees

In light of windstorm aftermath and a changing tree ordinance, we’re offering some tips on how to help minimize your tree troubles and keep our city looking lovely. 

Check back on San Marino Patch for more about the new tree ordinance and other important ordinances to know.

Local arborist Terry Chesbro, who's worked in the San Gabriel Valley for more than 35 years, gives insight on caring for trees: 

1. Trim Wisely 

Ultimately, every tree is different. Any ISA certified arborist will tell you: Each should be pruned based on personal factors such as history and structure.  

But don’t overdo it. While dead and diseased branches definitely need to go, “If a tree is virgin, all I recommend usually is thinning about 10 to 20 percent—thinning without over-stressing the tree,” says Chesbro.

Oaks in their natural environment, for example, “can be just deadwooded and maybe thinned a little now and then,” he continued.

2. Avoid Topping!

Chesbro says many of the 115 trees that fell in South Pas during the windstorm were because of topping, which is essentially when too much of a branch is removed—often done to reduce size.

See how many San Marino trees and other items were damaged in the windstorm here.

“It is extremely bad for the tree, because the cut that is left never heals over,” says Chesbro, adding, “The re-growth is weaker than the original top.”

And in that case, he does recommend maintenance: “You can’t just leave that tree to its own devices, because the likelihood of it being damaged is very high.”

The ISA offers this article for pruning young trees and these tips for pruning mature ones. 

3. Plant for the Worst

It's best to plant a variety of trees based on location and species. 

There are some tree species that stand up to strong winds much better than others. “Particularly deciduous trees—trees that lose their leaves—are usually safer, because the wind usually happens in the fall and winter,” notes Chesbro. 

(All trees are susceptible to disease. Here's a link that will help you determine if one of your trees is damaged.) 

4. Cut Back on Watering 

As Patch blogger Barbara Eisenstein put it: “Trees fail because we baby them. We over water them, so they don't have to develop deep, broad, supporting roots to get water.”

It's ideal to let trees—especially native ones—dry for about two to three weeks after a watering, says Chesbro. 

When watering your lawn frequently for short periods of time, “the abundance of water makes a thick heavy crown and … a weak root system, which is a recipe for blowing over,” he warns. 

5. Feed Your Tree

Use mulch to reduce loss of soil moisture and protect the tree roots.

“As the chips or the mulch decays, it puts nutrients back into the ground,”Chesbro says.

And leaves are good! “They should be left in the beds and doing their job.”

Terry Chesbro is an ISA-certified arborist and the owner of Chesbro Tree Care based in South Pasadena. He can be reached at (626) 799-4552.

See how to prevent a local tree pest from destroying your trees here.

How do you care for your trees? Tell us in the comments.