PLANT ECOLOGIST Kimberly Wahl-Villareal found herself battling a gnawing problem last year. Rats were making a nightly buffet of the tree seedlings at the United States Fish and Wildlife Service nursery she manages south of Alamo, Texas.
Because the nursery sits within the Lower Rio Grande Valley National Wildlife Refuge, full of rare wildlife, Wahl couldn’t use poison. Her only option was rat-proof barriers made of metal panels. But even though the nursery “looked like a spaceship,” Wahl said, some rats still managed to sneak in. Help finally came from the skies, when the refuge’s owl population developed a taste for nursery-grown rodent.
Young western white pine seedlings grow in the U.S. Forest Service nursery in Coeur d’Alene, Idaho. Credit: Chris Celentano/CDC Photography.
Rats aren’t the only problem pestering nurseries in the United States. One of the biggest challenges that nurseries face? Producing billions more tree seedlings in the next few years.
In the U.S., an area the size of California and Kentucky combined has reforestation potential, requiring as many as 40 billion trees. Forests can regrow on their own, but they often can’t do it fast enough. On U.S. Forest Service land, for example, natural regrowth only meets 40% of the reforestation need.
We must replant forests as soon as possible, experts say, or risk permanently losing these landscapes and their benefits for climate, water and more. Yet many nurseries are already producing as many seedlings as they can. Others are beset by labor, funding and seed shortages.
“These problems can be overcome,” says Eric Sprague, American Forests’ vice president of forest restoration. “This is the time for trees. If ever there was a moment to get people interested in a mass scaling-up of nursery capacity, now is it.”
To do so will take concerted action from the government, civil society and the private sector — as well as a few hungry owls.
A TICKING TREE BOMB
Each year, nurseries in the U.S. ship 1.2 billion tree seedlings to planting sites, enough to reforest 2.2 million acres. Yet a total of 131 million acres has potential to be reforested, with 20 million of those on public land and another 19 million on urban and suburban land, according to one recent estimate from The Nature Conservancy. This need grows by hundreds of thousands of acres each year as climate change fuels unprecedented wildfires, droughts, diseases and pest outbreaks, particularly in the western U.S.
Nursery superintendent Aram Eramian displays a conifer in its second, and final, year of growth at the U.S. Forest Service nursery in Coeur d’Alene, Idaho. Credit: Chris Celentano/CDC Photography.
If the U.S. wanted to reforest every last of these 131 million acres by 2030 — an ambitious goal — it would need an extra 2.8 billion trees each year, more than doubling the country’s seedling output. In a recent survey from American Forests and The Nature Conservancy, tree producers reported that, on average, they can boost seedling production by just one-third using their existing infrastructure. The survey’s respondents manage a total of 40% of the country’s nursery capacity.
Setting 2030 as a goal might seem like a quick turnaround in the slow-and-steady world of trees, but there’s reason to act fast. “A real sense of urgency is being driven by climate change,” Sprague says. With little time left to stave off cata- strophic climate change, we need to plant trees now to start securing their carbon sequestering benefits as soon as possible.
Another urgent factor, Sprague explains, is how swiftly invasive plants and other weedy species take over forests that have been decimated by climate change-fueled wildfires, droughts and other threats. It’s much harder and costlier to replant a forest once these invaders have taken hold. “The longer you wait the more of a challenge it becomes,” Sprague says.
For some nurseries, doubling production would be easy. At the sprawling U.S. Forest Service nursery in Coeur d’Alene, Idaho, a staff of 26 produces 4 to 5 million trees a year. Nursery superintendent Aram Eramian says that he could double the production of field-grown tree seedlings within two years, and he’d only have to hire one extra full-time employee to do so.
In Texas, things are more complicated. Wahl’s nursery is already at capacity — growing 114,000 seedlings a year — and the small private nurseries she contracts with are also maxed out. Doubling output would require doubling her workforce, securing more transport trucks, and finding more space to grow, store and sort seedlings, a process that can take a long time. Wahl, however, is eager to expand and is working to boost the nursery’s capacity to grow 156,000 seedlings within the next two years, and has longer-term aspirations to double that.
TAKING CARE OF BUSINESS
If time isn’t on nurseries’ side, then neither is labor. Many nursery jobs are seasonal and struggle to attract U.S. workers. Because of this, “a lot of nurseries rely on immigrant crews,” says Diane Haase, the western nursery specialist for the Forest Service. But as immigration rules are tightened, nurseries are “having a harder and harder time getting the crews that they need.”
Kuldeep Singh, nursery manager, inspects the roots of a conifer seedling in the L.A. Moran Reforestation Center greenhouse in Davis, Calif. Credit: Luciane Coletti.
Some nurseries in remote areas, Haase says, don’t even have access to migrant workers. They rely on retirees, which presents its own set of challenges. The local retiree pool is often limited, and older workers have physical limitations that younger ones don’t.
The L.A. Moran Reforestation Center in Davis, Calif., faces its own workforce concerns. Shuttered after state budget cuts in 2003, L.A. Moran reopened in 2017. It is now in the middle of a five-year ramp-up to its full capacity of 450,000 seedlings. The government agency that operates the nursery supplies lead horticulturalist Kuldeep Singh with inmate workers. But, because inmates aren’t allowed to work at the same location two days in a row, Singh contends with an ever-changing cast. “You teach them one day,” Singh says, “then they come the next day and you have to teach them again.” His job should get easier once he reaches an agreement with the California Conservation Corps, whose members can stay on-site longer and learn more of the intricacies of nursery work.
Beyond labor shortages, many nurseries are likely to be wary of scaling up for reforestation commitments that last for just a few years, Haase says. It takes a lot of money and time to secure more land and water, build new greenhouses and buy more equipment — and all the while, there’s no guarantee that this investment is worth the risk. Nurseries can spend two years growing an order of seedlings, Haase says, only to have a customer back out at the last minute. “It can really ruin your business.”
If nurseries were asked to massively amp up their seedling output, Haase explains, “they’d have to have some sort of guarantee that it would be worth their while … not just for five years, but for the longer term.”
NATURE VS. NURSERIES
Nurseries also deal with whole strata of complexity beyond typical business concerns. Trees are not “widgets,” Haase says. “They’re biological organisms.” And living things don’t always cooperate.
Take seeds. Often, nurseries have to collect seeds from the wild, which is tricky business. In Texas, Wahl’s team braves heat that “feels like a blow dryer” as they fan out to nab seeds from plant populations across the Lower Rio Grande Valley — the more diverse the genetics, the thinking goes, the better a replanted forest can withstand the whims of climate change.
Jessica Huang, seed bank manager at the L.A. Moran Reforestation Center, prepares to perform seed viability tests on freshly germinated seeds. Credit: Luciane Coletti.
The forest, however, can have its own ideas. Some years there’s poor pollination or an early drought, and plants don’t produce enough seeds to collect. Other years, there’s a late drought, and the plants abort their developing seeds. And sometimes there’s plenty of seeds, Wahl says, but by the time staff can get to it, “the animals already collected it.”
Wahl’s team, at least, can do its work from reasonable heights. In California, “cone collectors” like Robert Beauchamp sometimes ascend over 200 feet to nab the cones of giant sequoias.
During the frenzy of seed season, Beauchamp and his climbers pull brutal days zipping up and down lodgepole pines or Douglas-firs, then driving hundreds of miles overnight to repeat the process in other forests.
“It’s a very hectic, random schedule in doing the cone collection,” Beauchamp says. “Different foresters need me at different times, but when they need me, they need me within a few days.”
Many conifer species produce bumper crops irregularly every few years, and their seeds have frustratingly short collection windows. If Beauchamp gets to the cones a few days too early, the seeds won’t sprout. Wait for the cones to open or tumble to the ground, he says, and “you’ve lost your crop.”
Here, the whims of nature collide with the facts of labor and money. Singh, of the L.A. Moran Reforestation Center, struggles to get the specific low-elevation seeds he needs from cone collectors like Beauchamp, who usually collect high-elevation seeds for the Forest Service and timber companies. Singh is contemplating contracting a cone collector for his nursery, but it’s not cheap, and since cone collectors are in such high demand, they might not even have time for the nursery’s specific collection needs.
These seed issues are common. On average, nurseries have a 3.7-year supply of conifer seeds but just 1.4 years for hardwood species, according to the survey from American Forests and The Nature Conservancy. They might have plenty of one type of tree on hand, but not enough of another.
“In general, we don’t have enough seed banks that would allow us to scale up to the trillion trees that we’re looking for,” says Owen Burney, a silviculturalist at New Mexico State University. “Seed, I would say, is the most important piece because, without it, nothing else works. And it’s definitely a broken system.”
Burney also works on a different part of the “reforestation pipeline” that’s in need of a tune-up: how seedlings are raised. Traditional wisdom goes that the healthier a seedling is, the more likely it is to survive once it’s planted in the wild. With this in mind, nurseries coddle trees with plenty of water, rich soil and stable greenhouse temperatures.
But lots of these pampered babies fail once they’re transplanted to their final homes. Depending on the planting site, an acceptable death rate can range from 5% to 50%. Sometimes, as many as 90% of seedlings perish. Drought, heat waves and wildfires are a fact of life outside of nurseries — and climate change is only making these threats more extreme.
Nathan Zambino takes measurements and makes observations of a young tree with blister rust infection at the U.S. Forest Service nursery in Coeur d’Alene, Idaho. Credit: Chris Celentano/CDC Photography.
At the John T. Harrington Forestry Research Center, the Southwest’s biggest producer of forest seedlings, Burney and his colleagues are testing another approach. Within a few days of germination, the team deprives certain seedlings of water. They wait just to the point of wilting, then give them a good soaking. This boom-and-bust watering cycle continues until the seedlings are ready to be planted in the wild.
Burney hypothesized that this “tough love” can make trees more resistant to drought, and so far, his experiments are proving him right. Of 800 Ponderosa seedlings planted in conditions expected to be fatal to the young trees, 109 survived, and 92 of those were graduates of the tough love program.
Under a microscope, it’s clear what makes the tough love seedlings different: more efficient xylem, a tissue that acts both as a tree’s drinking straws and structural support. This novel research is eliciting “big interest” from nurseries, Burney says, and some are already testing giving seedlings less to drink. But Burney’s approach — meticulously watering and drying seedlings without killing them — is too labor-intensive for most nurseries. To reap the full benefits of tough love, new technology is needed, along with the money to fund it.
LET THE LIGHT IN
Money is always a concern, “but with the right policy and market signals, nurseries will be able to ramp up production,” says Sprague, of American Forests. “Ambitious goals to grow billions more trees this decade are certainly possible, but we need to scale up funding to meet the challenge.”
Conifer seedlings grow at the L.A. Moran Reforestation Center. Credit: Luciane Coletti.
It’s going to take the right combination of public investment, philanthropy and climate mitigation initiatives. Sprague cited The REPLANT Act, American Forests-led legislation introduced in the House and Senate in July, as one promising funding opportunity. If passed, the act would boost the Forest Service’s Reforestation Trust Fund for forestry work, including nursery development, from $30 million a year — an amount that hasn’t changed since the 1980s — to around $120 million a year.
But more is needed. The World Economic Forum’s 1t.org initiative offers a platform for governments, corporations and other groups to make pledges towards planting a trillion trees globally. American Forests, which leads the U.S. Chapter of 1t.org in partnership with the World Economic Forum, plans to build on the current momentum for reforestation to support nursery development across the country.
“As corporations, governments and NGOs make pledges to plant trees, this is our moment to say: You can’t do this without nurseries,” Sprague says. “It’s going to take leadership at all levels.”
Right now, American Forests is continuing to study the barriers to boosting nursery output, and how to overcome those barriers. No doubt there will be some surprises in the mix: that’s just the nature of the nursery business.
For Wahl, back in Texas, the spring brought its own major surprise: the coronavirus pandemic. For safety reasons, only one person at a time can currently work in the nursery. Without humans around to help out, even the owls couldn’t keep up with the rats. Wahl’s solution? Install stadium-style lighting to spook the rodents at night. Rats — like the other gnawing problems that nurseries face — are best tackled in the light.