Environment & Science

Climate change dogs efforts to save SoCal valley oaks

Vince Curtis stands in front of a mature valley oak. He hopes the ones he plants will someday grow this tall.
Vince Curtis stands in front of a mature valley oak. He hopes the ones he plants will someday grow this tall.
Sanden Totten / KPCC

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While world leaders are in Paris discussing ways to limit future green house gas emissions, others are thinking about what they can do to mitigate the effects of climate change in their backyard.

Carbon emissions that have already been released are likely to heat up the planet for decades to come, putting sensitive ecosystems at risk.

One local spot that could be in trouble is Cheeseboro Canyon in Agoura Hills. It's home to one of the southernmost populations of valley oak trees (Quercus lobata) in California.

To Vince Curtis, these trees make the valley what it is.

"They are just so big and beautiful and majestic," he said.

Curtis is a real estate appraiser and regular here at Cheeesboro. The valley oaks he loves are all over the canyon. They’re tall, gnarly trees with sprawling branches that blanket an area with shade, perfect for enjoying a picnic or a good book.

Valley oak(A young valley oak in a tree shelter growing near a mature oak tree in Cheeseboro Canyon.)

These trees haven't always been appreciated though. When ranchers first settled the area they cut many oaks down and planted non-native grasses that prevented new oaks from sprouting.

When Curtis found out about the plight of his beloved trees around 15 years ago, he sprang into action by volunteering with the National Park Service to plant new ones.

"I have been called the Johnny Appleseed of oaks," Curtis said. So far he's planted around 700 in the area.

He finds an acorn and then soaks it. Then he chills it in his fridge to fake winter conditions until it's ready to be planted.

"I put an acorn in, I put a little bit of fertilizer… and that’s it."

Johnny Acorn Truck

(The truck Vince Curtis uses to haul water and gardening supplies around.)

But Curtis said over the last five or so years, it's been too dry to plant new seeds. This could be a problem in the future, since scientists think long, dry periods like the current drought will be more common due to climate change. On top of that, temperatures are likely to be much hotter.

Valley oaks have evolved to thrive in mild summers and rainy winters, said Rosi Dagit, a biologist with the Resource Conservation District of the Santa Monica Mountains.

"The potential is there for the range of these trees to contract northward where they are less susceptible to as many hot days," Dagit said.

That could mean the oaks in Cheeseboro Canyon could die off.

This would have ripple effects, Dagit said, since valley oaks are "host to 5,000 species of insects, 58 species of reptiles and amphibians, 150 species of birds and 105 species of mammals that will disappear if those oak resources disappear."

Valley oak(A mature valley oak that recently lost about 25 percent of its mass, likely because of the drought.)

Scientists say the lack of precipitation in the current drought isn't necessarily a result of man-made climate change but that the above-average temperatures most likely are. 

Vince Curtis worries that dry spells like this will become more common. He's already seeing older trees shed limbs because of the prolonged drought.

"I hope the drought is just a temporary thing, we’ll see," he said.

If a Valley Oak can dig roots to the water table, it should be able to survive dry times. But when they are young, they need regular soaks.

Curtis said that's why it's important to help the young plants along. Lately he's been watering saplings about once a month with a bucket.

Vince Curtis(Vince Curtis pulls a pail of water from the bed of his truck.)

He's had some success. There's a hill in Cheeseboro covered in a dozen or so tall, healthy young trees that he planted 15 years back.

But for every grove like this, there are others that are just barely holding on. Curtis doesn't let that get him down.

"I just don’t want to give up thinking, 'oh, climate change is inevitable,' because that’s just not how things work out," he said.

He remembers fighting another battle that some called a lost cause. It was against a huge development planned for an area nearby. Many thought it was a done deal, but Curtis and a few others didn't give up.

Eventually, the development fell though, and now the land is public and part of the National Park Service.

"So climate change, development, it’s all not inevitable," he said.

"And yeah, I do think my grandkids will come out here, and I can say 'I planted that oak over there,' " he said.