PORTLAND, Ore. (KOIN) — A powerful heatwave in the Pacific Northwest is adding stress to trees that have already survived a heat dome, ice storm, and spring snow. Despite signs of stress, Portland Parks & Recreation tree specialists are sharing how to recover and revive trees.
The trees are also facing drought, despite the spring rain. PP&R tree specialist Alex Javier says it can take years for a tree to balance the moisture it lost, or adapt to lesser rainfall.
“Just because we have one good year of water, it’s not going to reverse the affects of drought,” Javier said.
Javier points out signs of stress are dried, drooping, browning, or curling leaves. He says the first thing to do is to dig out the top of the root from underneath the ground, called a root flare. It often looks like an elephant foot or a base of a wine glass.
“We like to say, let the flare feel the air.” Javier said.
Mulch is Javier’s preferred tool of recovery. It acts like soil by providing added nutrients, but can insulate the base of a tree from the heat as well as hold moisture for it.
When it comes to adding mulch, it’s important to give it space.
“If you pile up the mulch right up against the trunk, that heat can actually cook the living part of the tissue under the bark,” Javier explained.
Javier highlighted the three-by-three-by-three rule the city points to. Keep mulch three inches away from the base of the tree and exposed root, and spread mulch in a three foot diameter, about three inches deep.
Then comes watering. Portland Parks & Recreation is helping out people starting out in the free yard tree program by providing a five-gallon bucket with holes in the bottom. 15 gallons of water a few times a week in the summer months helps with a healthy tree. Poking holes at the bottom, Javier says, is better than just dousing a tree.
“This is a way to make sure it’s percolating like your coffee,” Javier said.
If a heat wave is coming, Javier says it’s a good idea to water a tree the night before so it can soak up the moisture throughout the heat.
For Portland’s city-owned trees, with over 1.2 million in the tree canopy, he says this strategy is hard to implement city-wide. It may mean the canopy will show the signs of a warming climate, given the years of extreme weather and drought conditions.
“When we have a hot and dry heat wave, we can’t get to all of the trees to give them extra water, so we are going to see more decline and less survivability just because of those things,” Javier said.