When a truck delivery of pine cones arrives at a reforestation center in Davis, California run by California’s fire agency, it starts a monthslong process—just one step in the complicated work to restore forests obliterated by wildfires.
Workers lay the cones out on racks, and flip them every day or two as they watch for the cones to start to open. When the cones are fully open, they go in a 90-degree Fahrenheit kiln to keep them open until the next day. Then they’re tossed in a giant tumbler that shakes the seeds out into boxes, and the seeds go in another machine that helps sort them by size. A preliminary x-ray shows which seeds are viable. Some seeds are cleaned by hand. After lab tests to make sure that the seeds can grow, they eventually end up in a giant walk-in freezer where they wait to be planted.
The process is complex, and it’s one reason why large-scale reforestation in the U.S. will be challenging. Around 133 million acres of land that were once covered in forest are available to be reforested now; on that land, there’s room for 68 billion trees. Because trees suck up CO2 as they grow, they could play a crucial role in fighting climate change. There’s bipartisan support for massive tree planting, and many companies have also started funding reforestation as a way to offset their own carbon footprints. But a new study points out an important bottleneck: right now, we don’t have enough seedlings to plant. To meet even half of the country’s potential for reforestation, nurseries would have to more than double their current production.
The challenge starts with collecting seeds. “There are just very few people who know how to do this,” says Austin Rempel, forest restoration manager at the nonprofit American Forests, which worked on the new study with The Nature Conservancy and several other partners. In many states, he says, there might be three or four people with the right skills. “It’s really hard to find people who are still collecting seed. Since it’s so competitive, no one’s really willing to even give you the phone number of their seed collectors, because they want that person working for them. And then the seed collectors don’t want to reveal where their seed trees are, because someone will come and steal them.”
For some species of trees, collecting seeds requires climbing to the top. And the harvesting has to happen at the right moment. “The foresters are watching their trees for about a year in advance to know if there’s a good cone crop coming,” Rempel says. “Then they start to gear up for a cone collection when they know the cones will start ripening. And then it gets more and more tense as the date approaches because you really only have this short window of time where the seeds are viable.”
Jessica Huang, the state seed bank manager at the reforestation center in Davis, says that a warm weekend might suddenly make pine cones start to open, so she’ll have to rush to find arborists who can climb trees to collect them. The seasonal, unpredictable nature of the work makes it harder to build up a workforce. The process differs by location, but always requires specialized knowledge. “Where I am, in Colorado, I talked to a seed collector whose entire job is going around and collecting seeds from places where squirrels have hidden them,” says Rempel.
There are other challenges, like the fact that agencies and nonprofits that need pine cones for reforestation might be competing with companies that want to use the cones in Christmas wreaths. Unscrupulous seed collectors might gather more seeds than they need, disrupting the natural process of regeneration in forests. Climate change is also threatening some tree species, putting more pressure to gather seeds before it’s too late. For some species, warming weather also means that seeds are produced less often or are more prone to disease.
There’s a need for funding and more workers: After seeds are collected, they have to be processed—and many states don’t have the capacity of California’s reforestation center. And after the seeds are processed, there’s a need for much more capacity in nurseries. Right now, nurseries grow around 1.3 billion seedlings a year. To dramatically scale up reforestation, they’d need to grow 3 billion a year. Because the work is often seasonal and sometimes in rural areas, nurseries have struggled to find workers. There also aren’t enough workers to plant trees and to maintain new seedlings after they’re planted. New support from the federal government will help, as Biden builds a Climate Conservation Corps to fight climate change. Corporate commitments to plant millions of trees are also helping.
“One thing we heard from all these nurseries is, yes, we can scale up, but we need to have some certainty that this tree craze isn’t going to end after next year,” Rempel says. In the past, he says, there were around 40 nurseries growing trees for the Forest Service alone. Now there are six. But that can change, and new nurseries can be launched around the country to help grow local species. As the system grows, it can create a meaningful number of jobs; the report says that each $1 million invested in rural reforestation can employ 40 people.
Without a concerted effort to plant trees, reforestation won’t happen. In California, areas that have burned in wildfires can sometimes regrow naturally, but the extreme fires in recent years have often been so destructive that seeds can’t survive. In eastern parts of the country, if a deforested area is left undisturbed, the wrong species of trees might grow back, or the area may stay a grassland. Nurseries can also grow seedlings that are more likely to resist disease, or provide species that are better adapted for future climate change.
Although it will be challenging to scale up the number of trees grown at nurseries, Rempel believes that it can happen. “The numbers are there—it’s within our grasp,” he says. “It’s also just really encouraging the change we’ve seen over the last couple years where companies are investing in tree planting and they’re also asking about survival and the full pipeline. They’re willing to fund some nursery development or post-planting care. And when that’s paired with proposals like Biden’s Climate Corps, that’s kind of magic stuff. Those two things acting together mean we can get there.”