Jon Dale’s love affair with birds began when he was about 10 and traded his BB gun for a pair of binoculars. Within a year, he’d counted 150 species flitting through the trees that circled his family’s home in Harlingen, Texas. The town sits in the Rio Grande Valley, at the convergence of the Central and Mississippi flyways, and also hosts many native fliers, making it a birder’s paradise. Dale delighted in spotting green jays, merlins, and altamira orioles. But as he grew older and learned more about the region’s biodiversity, he knew he should be seeing so many more species.

Treks to Santa Ana National Wildlife Refuge, which spans 2,088 acres near the border with Mexico, revealed an understory alive with even more birdsong, from the wo-woo-ooo of white-tipped doves to the CHA-CHA-LAC-A that gives that tropical chicken its common name. The preserve is one of the last remnants of the Tamaulipan thorn forest, a dense mosaic of at least 1,200 plants, from poky shrubs to trees like mesquite, acacia, hackberry, ebony, and brasil. They once covered more than 1 million acres on both sides of the Rio Grande, where ocelots, jaguars, and jaguarundis prowled amid 519 known varieties of birds and 316 kinds of butterflies. But the rich, alluvial soil that allowed such wonders to thrive drew developers, who arrived with the completion of a railroad in 1904. Before long, they began clearing land, building canals, and selling plots in the “Magic Valley” to farmers, including Dale’s great-great grandfather. His own father drove one of the bulldozers that cleared some of the last coastal tracts in the 1950s. 

Today, less than 10 percent of the forest that once blanketed the region still stands. Learning what had been lost inspired Dale to try bringing some of it back. He was just 15 when, in a bid to attract more avians, he began planting several hundred native seedlings beside his house to create a 2-acre thorn forest — a term he prefers over the more common thornscrub, which sounds to him like something “to get rid of.” He collected seeds from around the neighborhood and sought advice from the state wildlife agency, which began replanting thorn forest tracts in the 1950s to create habitat for game birds, as well as the U.S. Fish and Wildlife Service, which joined the cause after it listed ocelots as endangered in 1982. (The agency has since restored 16,000 acres.) The project kept dirt under his nails for the better part of a decade. “I’d go out and turn the lights on and do it in the middle of the night,” he said. “When I’m into something, that’s pretty much it.”

Two decades later, he’s still into it. He is a director at American Forests, which has toiled for 150 years to restore ecosystems nationwide. The nonprofit started working in the Rio Grande Valley in 1997 and took over the federal restoration effort last year. It also leads the Thornforest Conservation Partnership, a coalition of agencies and organizations hoping to restore at least 81,444 acres, the amount needed for the ocelot population to rebound. Although conservation remains the core mission, everyone involved understands, and promotes, the thorn forest’s ability to boost community resilience to the ravages of a warming world.

Climate change will only bring more bouts of extreme weather to Texas, and the Valley — one of the state’s poorest regions, but quickly urbanizing — is ill-equipped to deal with it. Dale, now 45, believes urban thorn forests, which can mature in just 10 years, provide climate benefits that will blossom for decades: providing shade, preserving water, reducing erosion, and soaking up stormwater. To prove it, American Forests is launching its first “community forest” in the flood-prone neighborhood of San Carlos, an effort it hopes to soon replicate across the Valley.

“People need more tools in the tool kit to actually mitigate climate change impact,” Dale said. “It’s us saying, ‘This is going to be a tool.’ It’s been in front of us this whole time.”

Despite its name, the Rio Grande Valley is a 43,000-square-mile delta that stretches across four counties in southernmost Texas, and it already grapples with climatic challenges. Each summer brings a growing number of triple-digit days. Sea level rise and beach erosion claim a bit more coastline every year. Chronic drought slowly depletes the river, an essential source of irrigation and drinking water for nearly 1.4 million people. Flooding, long a problem, worsens as stormwater infrastructure lags behind frenzied development. Three bouts of catastrophic rain between 2018 and 2020 caused more than $1.3 billion in damage, with one storm dumping 15 inches in six hours and destroying some 1,200 homes. Floods pose a particular threat to low-income communities, called colonias, that dot unincorporated areas and lack adequate drainage and sewage systems. 

San Carlos, in northern Hidalgo County, is home to 3,000 residents, 21 percent of whom live in poverty. Eight years ago, a community center and park opened, providing a much-needed gathering place for locals. While driving by the facility, which sits in front of a drainage basin, Dale had a thought: Why not also plant a small thorn forest — a shady place that would provide respite from the sun and promote environmental literacy while managing storm runoff?

Although the community lies beyond the acreage American Forests has eyed for restoration, Dale mentioned the idea to Ellie Torres, a county commissioner who represents the area. She deemed it “a no-brainer.” Since her election in 2018, Torres has worked to expand stormwater infrastructure. “We have to look for other creative ways [to address flooding] besides digging trenches and extending drainage systems,” she said.

A thorn forest’s flood-fighting power lies in its roots, which loosen the soil so “it acts more like a sponge,” said Bradley Christoffersen, an ecologist at The University of Texas Rio Grande Valley. Urban trees can reduce runoff by as much as 26 percent because their canopies intercept rainfall and their roots help absorb it, saving cities millions annually in stormwater mitigation and environmental impact costs. This effect varies from place to place, so American Forests hopes to enlist researchers to study the community forest’s impact in San Carlos, where Torres joined more than 100 volunteers on a sunny morning in December 2022. By afternoon, they’d nestled 800 ebony, crucillo, and other seedlings into tilled earth. “We need that vegetation,” she said. 

That sentiment has grown as cities across the Valley embrace green infrastructure. Although many swales and basins remain verdant with Bermuda grass, which is easier to maintain, there’s a growing push to use native vegetation for runoff control. Brownsville, the region’s largest city, is planting a “pocket prairie” of thorn forest species like brasil, colima, and Tamaulipan fiddlewood inside one drainage area. McAllen, about an hour to the west, has enlisted the help of a local thorn forest refuge to add six miniature woodlands to school playgrounds, libraries, and other urban locations. The biggest challenge to greater adoption of this approach is “a lack of plant distributors that carry the really cool native thornscrub species,” said Brownsville City Forester Hunter Lohse. “We’re trying to get plant suppliers to move away from the high-maintenance tropical plants they’ve been selling for 50 years.” 

American Forests doesn’t have that problem. Two dedicated employees roam public lands hauling buckets, stepladders, and telescopic tree pruners to collect seeds, some of which weigh less than a small feather. They typically gather more than 100 pounds of them each year, and stash them in refrigerators or freezers at Marinoff Nursery, a government-owned, 15,000-square-foot facility in Alamo that the nonprofit runs. 

That may sound like a lot of seed, but it’s only sufficient to raise about 150,000 seedlings. Another 50,000 plants provided by contract growers allow them to reforest some 200 acres. At that rate, without additional funding and an expansion of its operations, it could take four centuries to achieve its goal of restoring nearly 82,000 acres throughout the Rio Grande Valley. “These fields are probably one generation, maximum, from turning into housing,” Dale said.

Funding is a serious challenge, though. In 2024, American Forests began a $10 million contract with the Fish & Wildlife Service to reforest 800 acres (including 200 the agency’s job solicitation noted was lost to the construction of a section of border wall). That comes to $12,500 an acre, suggesting it could take more than $1 billion to restore just what the ocelots need.

Despite this, Dale says any restoration, no matter how small, is “worth the investment.” The nursery is currently growing 4,000 seedlings for four more community plots, each an acre or two in size. Small, yes, but they could mark the start of something much larger. “We have a vision to expand these efforts in the future,” Torres said. 

For now, nursery workers just have to keep the plants alive. During a visit on a sunny afternoon in February, 130,000 seedlings, representing 37 species, peeked out from black milk crates, ready for transplant. All of them are naturally drought-resistant and raised with an eye toward the lives they’ll lead. “We don’t baby them or coddle them,” senior reforestation manager Murisol Kuri said. “We want to make sure they are acclimated enough so when we plant they can withstand the heat and lack of water.” 

Despite this, on average, 20 percent of plants die, partly due to drought. It underscores the complexity of American Forest’s undertaking: While thorn forest restoration can help mitigate climate change, it only works if the plants can stand up to the weather. The organization expects that in the future, species that require at least 20 inches of annual rainfall could perish (some, like the Montezuma cypress and cedar elm, are already dying). That doesn’t necessarily doom an ecosystem, but it does create opportunities for guinea grass and other nonnative fauna to push out endemic plants. Removing them is a hassle, so it is best to avoid letting them take root. “If you don’t do this right, it can blow up in your face,” Dale said. 

Hoping to evade this fate with its restored thorn forests, American Forests has created a playbook of “climate-informed” planting. The six tips include shielding seedlings inside polycarbonate tubes, which ward against strong winds and hungry critters while mimicking the cooler conditions beneath tree canopies. They look a bit weird — a recent project at Laguna Atascosa National Wildlife Refuge features about 20,000 white cylinders lined up like tombstones — but seedling survival rates shot up as much as 90 percent once American Forests adopted the technique a decade ago.

Another strategy seems abundantly obvious: Select species that can endure future droughts. “If we’re not [doing that], we’re kind of shooting ourselves in the foot,” Dale said. Christoffersen, the University of Texas ecologist, and his students have surveyed restoration sites dating to the 1980s to see which plants thrived. The winners? Trees like Texas ebony and mesquite that have thorns to protect them from munching animals and long roots to tap moisture deep within the earth. Guayacan and snake eye, two species abundant in surviving patches of the original Tamaulipan thorn forest, didn’t fare nearly as well when planted on degraded agricultural lands and would require careful management, as would wild lime and saffron plum. 

Altering the thorn forest’s composition by picking and choosing the heartiest plants would decrease overall diversity, but increase the odds of it reaching maturity and bringing its conservation and climate benefits to the region. A 40-acre planting at Laguna Atascosa National Wildlife Refuge on the Gulf Coast reveals how quickly this can happen. Five years ago, a tractor wove through the site cultivating sorghum, which gave way to 40,000 seedlings. Today, the biggest trees stand 10 feet tall, with thorns high enough to snag clothing.

Dale named some of the 40 or so species now thriving in the south Texas sun: eupatorium, yucca, purple sage, colima, vasey’s adelia, load bush, catclaw acacias. The plants feed and shelter a staggering array of orioles, green jays, and other birds, whose whistles, caws, and tweets filled the air. “I’ve already heard 15 species since we walked in,” Dale said. He puckered his lips and, with the expertise born of a life spent birding, made a distinctive pish sound to draw them out. The brush was too thick to see them stir, but Dale seemed pleased as he surveyed it. “It’s gone from being this very homogenous use of land … to life again.” 

An hour to the west, visitors to San Carlos’ community forest might struggle to imagine that transformation. The ebony, crucillo, and other species planted two and a half years ago still look scrappy, and a seesaw pattern of droughts and winter freezes helped claim more than 40 percent of the seedlings. Still, the humble thorn forest has garnered a lot of interest from young visitors. “I’ve been in the [community center] working with children and they ask, ‘What is that over there?’” said Mylen Arias, the director of community resilience at American Forests.

This little patch of the past does more than preserve the region’s biological history or defend it from a warming world. It’s an attempt to reverse what naturalist Robert Pyle calls an “extinction of experience.” Most people have never even heard of a thorn forest, let alone witnessed its wild beauty at Santa Ana. Dale and those working alongside him to revive what’s been lost want others to know the value this ecosystem holds beyond saving ocelots or mitigating climate change. His grandfather was a preacher, and that influence is evident as he speaks of the “almost transcendental” feeling he gets simply being in nature. “I’ve talked to people, and it’s like, ‘Do you know how this is going to enrich your life?’” 

He often shows people photos of the backyard thorn forest he started 30 years ago, hoping to convey what’s possible with just a bit of effort. Days after planting the first Turk’s cap and scarlet sage, hummingbirds fluttered in to sip their nectar. Within a few years, the canopies of Texas ebony and mesquite trees unfurled, providing shade and nesting locations for birds, including the white-tipped doves and chachalacas he’d hoped to see. It wasn’t easy to let go of it when his mother sold the house last year. “But you created it all,” she told Dale. “Mom,” he said, “I can do this somewhere else. That’s the point.”