The endeavor to grow forests that can take on the future impacts of climate change

By Austin Rempel

CLIMATE-RESILIENT REFORESTATION is going to look different in every part of the United States. But it will be — and already is — important everywhere, given the dire need to adapt to the rapidly changing climate.

One such place is California, where wildfires have ravaged more than 6.5 million acres since 2015. But this summer seemed to foreshadow a scale far worse. In one week alone, lightning strikes sparked hundreds of wildfires that devastated 1 million acres and killed countless trees. The state’s megafires are visual, visceral examples of climate- driven disasters. The 2018 fire that burned the mountain town of Paradise — known as the Camp Fire, which was California’s deadliest and most destructive wildfire ever — shocked the nation and showed just what might be in store for forests and people as climate change heats up.

But the Camp Fire burn scar has also emerged as a landscape-sized laboratory where a group of forward-looking forest scientists and land managers from American Forests and elsewhere are pioneering ways to grow future-ready forests that can withstand the impacts of climate change. This is a story about some of the places and people at the heart of that effort.

THE CONCOW RESILIENCE PROJECT

The Camp Fire burned almost 240 square miles — an area the size of Chicago — and killed 85 people. It destroyed nearly 19,000 homes and businesses in Butte County, Calif., and leveled the towns of Paradise and Concow.

But the Camp Fire was only the latest in a series of severe wildfires to hit the region. Foresters and landowners were ready to try something new, given a hostile new climate coming into focus — one with earlier springs, hotter summers and more severe droughts — and forests clearly unequipped to withstand such conditions, partly due to years of suppressing fires. They saw the burned landscape as an opportunity to try to grow a forest that could withstand these harsh conditions.

“The gift that the Camp Fire gave us is that it helped us to see what isn’t working. People became permeable to new ideas,” says Wolfy Rougle, the forest health watershed coordinator with the Butte County Resource Conservation District.

In 2019, Rougle assembled local land managers, climate scientists and nonprofit leaders, including Brittany Dyer, American Forests’ California state director. In a series of walks across the charred landscape, they began to envision what a more climate-resilient forest might look like and how to get there.

They chose to focus on Concow, in part because of its unique history of burning in large wildfires, including the Camp Fire. What they learn may guide forest adaptation across California’s low-elevation foothills — millions of acres in total — that are warming up and drying out faster than almost anywhere in the state, outside of the Mojave Desert.

Early on, the group outlined their vision for the restored landscape. They seek to sustain the region’s forests which, with fires and sustained drought, are gradually being replaced by highly flammable shrub fields. The forests they’re imagining will have fewer trees, and the trees will be larger and more widely spaced than those in today’s forests. A less dense forest will be able to weather fires, beetle outbreaks and droughts, and allow trees to accumulate carbon in their roots and trunks, and in the soil beneath them. Healthy forests function as a carbon sink — helping to reduce the amount of carbon dioxide in the atmosphere, rather than releasing it back to the skies every time a disturbance strikes. A restored watershed would also provide clean and abundant water supply for those living downstream. And Concow residents, many of whom chose to live in the region for its forests, would enjoy safer economic and recreation opportunities.

“We have a moral obligation to replant the Concow region through a climate-smart lens,” Dyer says. “It would be nice if there was a silver- bullet-like solution — but there isn’t. Conditions are changing under our feet (literally), but by finding climate-smart solutions, we can redefine what it means to live in Paradise for years to come.”

The group is bringing its vision to life by testing three different reforestation approaches in the hardest-hit parts of the region. Their motto is short and sweet: “Plant trees. Not too many. Mostly oaks.” They aim to learn as much as possible and to do so as fast as possible.

“We need to try a lot of different things,” Rougle says. “A lot of it might not work, but a lot of conventional reforestation doesn’t work — so why keep doing only that?”

BRING BACK THE OAKS

The first approach is to nurture oak trees that survived and re-sprouted after the fire. Oaks are the only tree that are coming back in most parts of the burn. Even when an oak’s top completely burns, it can re-sprout from its root system.

There aren’t many big oaks left. Locals cite the culprits as a history of intense grazing and logging; a lack of regular, small fires that clear out some of the vegetation; and, conversely, too many big fires. But oaks may be key to building a more resilient forest. Rougle plans to give the oaks a helping hand by thinning competing shrubs so that the young trees have more room to grow, pruning to encourage them to grow up and out of the reach of flames, and jump-starting growth of a grassy understory, rather than one dominated by shrubs. The goal of this is to see whether an oak savannah can be coaxed into existence.

Signs that oaks may be a climate-smart bet are everywhere in California. The state’s oak savannahs — grasslands interspersed with massive, umbrella-shaped oak trees — are common at lower elevations. Oaks tend to dominate in areas where the climate is already as hot and dry as we expect the Concow area to be in coming decades. And oak savannahs are resilient to fire. A grassy understory with a few large trees can accommodate fire much better than an overgrown forest where flames easily race from treetop to treetop.

And Rougle has noticed yet another clue: acorn grinding stones are everywhere, left by the Concow Maidu, the Native American tribe that is indigenous to the area.

“You even find them on ridgetops, rather than just alongside rivers where I’m used to seeing them,” Rougle says. “And the grinding stones are deep, meaning they were used generation after generation.” This suggests that, not too long ago, the region was full of large oaks, likely maintained with regular prescribed fires set by the Concow Maidu.

FORESTS FORGED WITH FIRE

The second reforestation model the group pro- poses explores whether young trees can survive, and possibly even benefit from, prescribed or controlled fires. They aim to create a landscape similar to what the Concow Maidu cultivated centuries ago — one adapted to and maintained by fire. Many foresters would be shocked by the idea of intentionally setting fires anywhere near planted trees. But, in California and many other parts of the American West, reforestation efforts will need to accommodate this type of “good fire.” The emerging collaboration between fire practitioners and foresters has created a new field of study called pyrosilviculture.

It’s not just public land managers who see the benefits of good fire. Landowners in the Camp Fire area also are eager to figure out how it can be done. For her master’s thesis, Rougle surveyed Butte County residents whose land burned in the fire. Seven out of every 10 landowners were interested in applying prescribed fire to their land.

Eight out of every 10 said they wanted to replant. But the most surprising thing she discovered was the overlap between the two — landowners want reforestation programs that allow prescribed burns. In fact, 59% of surveyed landowners who expressed interest in reforesting their land also hope to safely burn that same land someday.

The Butte County Resource Conservation District, where Rougle works, has started a prescribed fire association. It is a means for landowners to come together to complete small, home-scale burns. At some point, the region may be able to escape the cycle of catastrophic wildfire, thanks to regular application of good fire by a community of local forest tenders.

Cluster planting may be a way to reconcile the seemingly conflicting goals of reforestation and prescribed fire. Simply put, cluster planting is like social distancing for trees. It involves planting seedlings in clumps or patches at a distance from each other. The best growing spots are targeted, and patterns of natural regeneration are mimicked. There’s a tantalizing possibility that this could make it harder for fires to jump from clump to clump.

Cluster planting is different than traditional planting, where foresters plant in neat, densely packed rows to help trees outcompete other vegetation. The wisdom of this practice — “pines in lines” — hinges on the ability to come back with chainsaws to thin out young trees before they start to crowd each other. If they grow too close to each other, flames can easily spread from tree to tree, putting the whole stand at risk of burning.

But this follow-up care is expensive and often falls by the wayside. Due to endless budget cuts, foresters are forced to let the young stands fend for themselves. One recent analysis showed that 57% of the plantations established in the Sierras between 1993 and 2016 have never been thinned. Now more than ever, we can’t just plant “pines in lines” and walk away.

ASSISTED MIGRATION

The last approach being trialed focuses on whether conifer seed sources from warmer and drier sites might outperform the traditional, local seed sources.

Here’s where Dr. Jessica Wright — research geneticist at the U.S.D.A Forest Service Pacific Southwest Research Station, and one of the scientists that Rougle invited to the Concow region — enters the picture. Her research team is quickly revealing that the forests growing today are already out of sync with our current climate, much less the climate we can expect 50 years from now. This concept of trees lagging behind a rapidly changing climate adds a whole new dimension to the idea of “right tree, right place.”

Wright is carefully selecting Ponderosa pine seeds from various parts of California to see if any lead to faster growth and higher survival in Concow. How much do tree genetics matter? A lot, according to research conducted else- where. Trees from southerly latitudes and lower elevations may grow faster, invest more of their energy into root growth in preparation for drought or have needles that surrender less water.

“Every reforestation project is an opportunity to find the best seed for that site,” says Wright.

There’s also increasing recognition that more seeds need to be collected from mother trees that may have “survivor” genetics. These are trees that have demonstrated resistance to beetles, droughts and diseases. They are the last ones standing after a tree-killing event. Or they are trees that have found a way to survive in especially harsh environments. Forest researchers are busy testing these ideas in the Lake Tahoe Basin — 100 miles southeast of Concow — and elsewhere in the U.S. The hope is that increasing the number of trees on the landscape with these survivor genes could speed up adaptation and help forests survive and thrive in the coming century.

LIFEBOATS FOR TREES

A mile and a half west of Concow, American Forests is also working with the federal Bureau of Land Management (BLM) to formulate a plan to restore the burned land that is under the agency’s care.

One of the more promising approaches is trying to pinpoint places where seedlings may have an edge. Seedlings have none of the advantages that adult trees do, like deep roots to tap groundwater, thick bark to buffer them from bouts of extreme weather, and high branches that avoid the reach of flames. Survival often comes down to luck — a string of wet, cool years in early life, for example, or having a rock or log nearby to shield them from the heat of the day.

To boost their chances of surviving, it’s important to choose the right places to protect and the right places to plant. Certain spots, for example, may shield trees and seedlings from the worst of climate change. Scientists call these special spots “refugia.” The hope is they can act as lifeboats when large landscapes experience big, forest-killing events.

At the highest level, refugia are parts of the forest where something akin to a hack allows them to survive even the worst weather. For example, in the desert southwest, stands of piñon pine have been discovered in the middle of miles and miles of dead forests that succumbed to drought. Research suggests that these stands were sustained by access to rare groundwater seeps. In the northern Rockies, whitebark pines perched on rocky cliffs continually evade fires and waves of beetles because nothing can reach them.

Some of these safe zones immediately catch one’s eye in the Camp Fire scar, too. For example, trees surrounding Concow Reservoir have repeatedly escaped the worst of the fires, likely due to the higher humidity and cooler air temperatures around the lake. Other examples stand out too — like the lone gray pines that avoided the brunt of the blaze by virtue of growing apart from other plants, on the harshest, driest soils and steepest slopes, where flames couldn’t reach.

In the Concow area, below the barren, scorched hillsides, there’s a small mountain stream trickling at the bottom of a steep ravine. It’s shaded here for much of the day and feels about 10 degrees cooler. Yellow-legged frogs and rough-skinned newts breed in the stream’s shallow pools. This ravine is where American Forests planted the most sensitive seedlings, including Douglas-fir, which is projected to disappear from most of the Camp Fire area as temperatures soar.

It’s places like these — and the involvement of people like Rougle, Wright, Dyer and countless landowners in the Camp Fire area who’ve shown remarkable resilience and commitment to finding innovative solutions — that are our greatest hope for future forests in a time of climate change.

Austin Rempel writes from southwestern Colorado and is American Forests’ senior manager of forest restoration.