He Speaks for the Trees

Bryan Vejar explains Caltech’s tree population to a group of students. Photo: Lance Hayashida/Caltech

by Andrew Moseman

Here is one of the first things you’ll learn about Bryan Vejar: he used to climb trees at Disneyland.

In the dark of night, when the paying customers had left the happiest place on Earth, Vejar and the rest of the arborist crew pruned trees around the park and checked for hazards like limbs about to fall. In places that could not be reached by platforms or lifts, he climbed trees by hand. All the while, empty rides kept on running so technical crews could ensure they were safe for the next day’s guests.

“It's quite a surreal thing to be climbing in the middle of Thunder Mountain at midnight, with all the rides going around and all the animatronics going off,” he says. “It's gnarly.”

These days, Vejar can still be found in the trees, but those next to Moore Walk rather than the Mad Tea Party. For the past three years, he has been Caltech’s arborist, the person charged to care for Caltech’s distinct population of trees and plan for the future campus treescape. Through outreach efforts like the newly formed Caltech Tree Corps (CTC), Vejar also promotes the value of trees to the greater community and helps everyone see the majesty all around them.

“There's this concept called ‘plant blindness,’” he says. “You can be walking under the trees but not even notice them, which is crazy because there are these gigantic, living, dynamic life forms all around us that are tremendous. If there was a giant whale next to you, you'd be saying, ‘Oh my God, what an amazing thing.’"

On an arid May afternoon, in the broad shade of a coast live oak that stands next to the Thomas J. Watson, Sr. Laboratories of Applied Physics, Vejar invites a group of about 20 students to see Caltech through his eyes.  

Like so much of greater Los Angeles, Caltech is an amalgam of imported trees and native flora. (See all of them on Vejar’s interactive map of every tree on campus, and find him as @caltecharborist on Instagram.) Giant Engelmann oaks, such as the one just northwest of the Red Door Cafe, have stood over this land for centuries. Other native plants, like the coast live oak, offer habitat for an array of other local species. Alongside them grow imports like the iconic towering palm trees that have come to symbolize Southern California, the ubiquitous and fast-growing eucalyptuses, and the South American jacarandas that litter campus with purple springtime confetti.  

One of Caltech’s jacaranda trees in full bloom. Photo: Lance Hayashida

Though they are living things, trees give the impression of being unchanging, eternal. In fact, Caltech’s trees are forever in flux. Campus is home to more than a hundred coastal redwoods, many of which live in clusters near the Catalina Apartments that house Caltech graduate students. But these majestic trees, native to more humid parts of California and accustomed to pulling water from the air, struggle under the ongoing drought conditions Pasadena now endures.

When opportunities for planting new trees arise, such as times when the Institute transforms itself through the construction of new buildings, Vejar often advocates for planting more native species that are adapted to the local climate. However, his first concern is to develop a diverse and robust canopy of trees that can thrive as they make campus a better place.

“I used to work for a native landscaping company, and that galvanized me toward planting natives all around us, because natives are so important for our local ecology, our local pollinators. They're little oases for our native urban wildlife that has been here far before us, and hopefully will be here long after us,” Vejar says.

“Having said that, I've come around on the idea that there is a role for non-native species that are climate-adaptive, as long as they are non-invasive. We have a lot of species from the more arid Mediterranean climates—Australian trees, Southeast Asian trees, trees that would do well in our climate as it worsens, as it gets hotter and as water becomes more restrictive. There is certainly a valuable role for non-native species in and around our campus and, honestly, anywhere in California.”

Ask Vejar to name the benefits of planting and protecting trees and he will provide a long list. Most obviously, the shade of Caltech’s 3,000-some trees protects the community from the unrelenting California sun. “If trees did nothing else but give us shade, they'd still be worthwhile,” he says. “But they do much, much more than that.”

The Englemann oak near the Hameetman Center. Image: Lance Hayashida

Trees offset the urban heat island effect, created when the sun radiates off hard surfaces such as pavement and increases the ambient temperature. Trees retain a large amount of water and transpire that water into the air, thereby cooling it. This effect makes the area around them more hospitable for humans and other species. Trees also filter out air particulates that can cause pollution and sequester carbon, slowing climate change.

Those are just the physical benefits. Vejar says there exists a well-researched positive correlation between the tree canopy, social health, and mental health. An abundance of trees, he notes, leads to feelings of relaxation and decreased stress.

“If you've ever walked into an affluent neighborhood, what's the first thing you noticed? It feels cooler; it feels safer; it feels nicer,” he says. “Generally, that's because their canopy is more developed and well maintained. Whereas, if you go to areas that are historically underserved, or some BIPOC [Black, Indigenous, and People of Color] communities, or lower income areas, there's a lot less green space, and there's a lot less tree cover. This adds to feelings of discomfort.”

While campus is a lush, green place, many parts of greater Los Angeles, including some of Caltech’s neighboring communities in the San Gabriel Valley, are relative tree deserts because of this kind of historic inequality. Vejar aims to change that. This year, he started the CTC as a way for Caltech students, staff, and faculty members to plant trees in neighboring communities. In May, as an example, CTC members joined a volunteer effort to put trees into a park in Claremont, California.  

“There are so many different things we could do to edify our communities, to fight climate change, to reduce heating costs, to improve quality of life in our neighborhoods,” he says. “Trees are probably one of the easiest, if not the most simple, straightforward thing we could do to address many of the problems. But we need to plant them, and we need to plant them now. That's what the Tree Corps is doing here. We are trying to get shovels in hands, and we want to get trees in the ground, full stop.”

From the print edition: Vejar chooses five of his favorite trees.