On Friday, July 11, a team of volunteers with local nonprofit Amigos de los Rios watered trees in Altadena as the summer sun beat down, working against time and Mother Nature to stave off another tragedy in the Eaton fire’s wake.

The town’s remaining trees — survivors of the catastrophic wildfire and the months-long debris removal process  — now face another threat: A lack of water, thanks to destroyed irrigation systems, leaves thousands of trees in danger of not making it through the summer, according to local arborists.

“You might not see some of these trees die for years, but the consequence of not acting this summer is significant,” former Pasadena forester and consulting arborist Rebecca Latta said. “Even if the results are going to be stretched out over a period of time, you might be able to trace the decline of the tree back to this one event, this summer when they didn’t get any water.”

Latta said arborists in Lahaina, Hawaii, where an August 2023 wildfire burned more than 2,000 acres and left 102 dead, shared a warning for what could occur in Altadena. After saving trees during its debris removal process, Lahaina lost many of those trees during the summer due to lack of water.

Claire Robinson helped found and now serves as managing director for Amigos de los Rios, an Altadena-based urban forestry and natural infrastructure nonprofit. Robinson lost her home in the fire as well as the irrigation system that would provide water to both private and public trees.

“It’s really a community that was known for its trees, some of the oldest trees are over a hundred years old and they have just an incredible presence as a sense of place,” Robinson said. “Like grandparents, like ancestors.”

Both Robinson and Latta have reached out to Los Angeles County to flag the concern, but have been told that the county does not have the funding to support the needed watering effort. Latta estimated that it would cost somewhere between $750,000 to $1 million to fund watering for the next one to two years.

That’s why Robinson and the Amigos de los Rios team has taken it upon themselves to do what it can in partnership fellow local organization Altadena Green.

Trucks with two 150-gallon water tanks have been driving around Altadena for the last month providing water to more than 300 trees on private residences and as many street trees as they can help.

The problem is there’s no way to get to every tree in need. Robinson said in a perfect world, every tree would be watered every two weeks. Some older mature trees need about 200 gallons of water while younger trees only need about 10 gallons.

According to the county, there are 5,600 undamaged trees and 3,030 damaged trees that are county-maintained within the Eaton fire area. Public works has removed 950 dead trees and will evaluating the damaged trees every three months to monitor recovery.

Watering is not typically part of ongoing maintenance for county-owned trees, according to the county. Public works ensures watering of newly planted trees for the first 90-days and then the responsibility of watering shifts to property owners for the three-year establishment period.

“Public Works arborists are conducting ongoing inspections to monitor the health of street trees within the fire-impacted areas,” a county statement read. “If a tree requires supplemental watering and the homeowner is unable to provide it, Public Works will supply the necessary watering as directed by County arborists until the homeowner is able to do so.”

To water a tree properly means watering around the drip line, or the widest part of the tree, and not at the trunk. The soil must not be too compacted so water can get to the roots. For a large oak tree, Robinson said, watering might be done 20-feet from the trunk.

Local arborists estimate that the Eaton fire cost Altadena about half of its trees. Another 25% to 30% were lost during the debris removal process. Robinson said by not acting this summer, Altadena could be down to 12% to 15% of its pre-fire tree canopy.

“I don’t think we all realize how unlivable our community is going to be if we lose any more trees,” Robinson said.

She said the prospect of that keeps her up at night. Amigos de los Rios planted hundreds of trees in Altadena thanks to grant funding in the last few years and within a couple weeks of the fire it went to the county to say that the young trees that survived would need more constant care than the mature trees.

Latta said trees are what keep temperatures in Altadena reasonable, and losing more could create a heat island effect. More open space that reflects the heat back up without the buffer of trees amplifies the heat impacts.

“They’re knocking the spikes off those high heat events,” Latta said of trees.

In addition, trees help with filtering pollution and collective rainfall.

“They’re critical for livability in a place like that,” Latta said. “If they want people to move back into Altadena, or people want to move back into Altadena, they’re going to need shade for it to be comfortable.”

When the time is right, Robinson said, a plan is in place to start replanting trees in Altadena but that it will take a 50-80-year cycle to get back to the tree canopy the town had pre-fire.

“We’re really worried that as it gets hot a lot of these trees are going to be stressed and succumb to beetle damage because the beetles are already up there attacking the dead trees,” Latta said. “There’s nothing to stop them from attacking stressed county street trees.”

For information, visit altadenagreen.org.