Daniel Laughlin walked out into an unusual garden.
“I haven't been here in about a month,” Laughlin, a botanist at the University of Wyoming, said with a chuckle. “I don't know what to expect.”
That’s because all around him is a black burnt forest covering the mountainsides, left by the Mullen Fire of 2020. He walked down the rows of plants protected inside plastic nets. They're spaced four feet apart and in blocks of 10 of each species. The garden was planted in the spring, and he wasn’t sure if it would still be alive.
“ There's a lot of interest in trying to understand tree regeneration following wildfire events,” he said. “But more broadly, we're interested in how trees are going to regenerate and move across the landscape in response to drought and fire in general, and changing conditions.”
You might be thinking – wait. Trees are rooted. They can’t move.
“These trees have been marching across the continent for the last 40 to 50 million years, some of them,” Laughlin said last year when he first started this research. “They're not doing it as individuals – they're doing it as populations. Their seeds are traveling far distances, and understanding these dispersal rates is really part of the puzzle. The paleo record is absolutely clear that trees have been on the move and that they're quite fast in their dispersal, especially these long-distance dispersal events that are likely triggered by relationships with birds that are moving seeds around these far distances, especially things like Clark's nutcracker, for example, with pine trees up at high elevation.”
He got curious about this when he studied arboretums across the U.S. and found 188 different species of trees often only grow in about 25% of their actual thermal niche. That means they can grow in a much wider array of climates than where we’re used to seeing them. This garden was testing that.
“ This is a pinyon pine,” he said. “It doesn’t normally grow at elevations of 8,600 feet. So this is actually testing its cold tolerance by bringing it up this high.”
This study asks: Can pinyons or other desert plants move up in elevation as the climate warms?
“I would say of the 10 pinyon pine we planted, seven or eight are still going strong,” Laughlin said.
But also: Can high mountain trees and plants move down?
He bent over and looked inside another net. “ Here's one we haven't seen yet. This is bristlecone pine.”
Normally, bristlecone pines live at the tops of mountains.
“Yeah. Let's see. That's one, two, three,” He peeked in each net, counting how many seedlings survived this year’s dry summer. “Three out of four, five, six, seven … So I think we got 80% survival.”
Ponderosas, subalpine firs, junipers – 10 tree species total, plus dozens of smaller flowers and bushes.
“I think they have much broader environmental tolerances than we give them credit for. But we don't know exactly in which direction those tolerances go. Are they more warm-tolerant, more cold-tolerant? Can they be both?” Laughlin asked.
If we figure that out, he said, we might be able to help these plants survive.
“One of the most controversial management strategies under climate change is this idea called assisted migration, that some species might do better in other places as the climate changes, but they can't disperse there fast enough.”
The Medicine Bow Mountain Experimental Garden Array, or Med Bow MEGA, is testing whether humans could speed up that movement by planting species outside their comfort zone.
Laughlin was happy with what he was seeing here.
“We've surveyed all of these about three weeks ago, and it's approximately 90% survival across all of the plants,” he said.
If it works, he said, we’ll need to ask ourselves some hard questions. Like, whether to help trees migrate to stop the spread of grasslands.
“We've seen type conversions from forest to grasslands and shrublands all over the West, and they have attributed that to a lack of recruitment following fire and drought,” he said. “There's nothing inherently wrong with grasslands and shrublands either. They're probably great wildlife habitat.”
But since it's humans that caused these droughts and wildfires, he said, maybe helping forests relocate is the right thing to do.
“ I think we do need to be more open-minded about what future landscapes would look like,” Laughlin said. “We have a connection to these historic classic landscapes, and we want to make a positive change and restore what we lost. We need to be open to the possibility that what our kids and grandkids will be recreating in might have to be quite different than what we were used to.”
This autumn, Laughlin and his crew checked in on the gardens. Some trees didn’t do so well, like the desert pinyons and the high mountain subalpine firs and Engelmann spruce. But other mountain trees? Douglas fir, lodgepole pine, ponderosa, bristlecone and limber pines, and the desert juniper – over half survived the move.
As long as Laughlin keeps getting funded, he plans to watch these gardens over the years.
