After California’s Park Fire, A Second Bloom of Milkweed

This article is part of The State of Science, a series featuring science stories from public radio stations across the United States. This story, by Danielle Venton, was originally published by KQED.

Don Hankins examines a bright yellow-green patch in the meadow. The land all around is charred by fire. But here, there’s a sort of miracle at work. Native milkweed has sprung up and bloomed for the second time this year. This is not something these plants, Asclepias eriocarpa, also known as Indian milkweed, are known to do.

They bloomed in late spring and early summer and had already done so this year when the Park Fire roared through. But the fire seemed to happen at just the right time to coax a second flowering, one that is likely to line up with the return migration of the monarch butterflies south to overwinter in Mexico. Monarchs rely on these flowers to complete their life cycle. For researcher Don Hankins, this is a surprise delight.

“We may be coming back into some knowledge here that hasn’t been practiced in a long time,” said Don Hankins, a professor at Chico State, who teaches classes in geography with a focus on fire. He is also a California Plains Miwok traditional cultural practitioner.

Native tribes of Central California tended milkweed with fire and used the plant’s fibers in feather belts, weaving the fibers together with feathers from important bird species into velvet-like textiles decorated in geometric patterns. While milkweed and such birds were once abundant, today, they are comparatively rare.

Hankins’ research uses indigenous “eco-cultural” knowledge to detect signs of healthy landscapes and to draw lessons on how to steward. So he is fascinated that this year, the milkweed meadow at the Big Chico Creek Ecological Reserve will get another round of flowers and maybe another set of seeds. And the butterflies got an extra meal and a chance to lay eggs. Hankins suspects tribes knew how to time fires to achieve the same thing.

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Monarch butterflies, painted in brilliant orange, black and white-spotted wings, are known for four main things. Their iconic, spectacular coloring advertises they are poisonous to eat. Each year, the butterflies migrate thousands of miles, overwintering in Mexico and California in large clusters of trees. Their larvae won’t survive on anything but milkweed. Monarch butterflies are near the brink of extinction, their population having declined by 99.9 % since the 1980s. Increasing milkweed habitat is crucial to the species long-term future.

“I’m actually really excited to share this with folks, to understand it,” Hankins said, “because it’s really phenomenal to see [milkweed] resprouting so vigorously. It is by far the tallest thing out here at this point in time on the ground.”

Observers have already noticed monarch larvae on them.

A Phoenix Landscape Holds Lessons

The Park Fire, California’s fourth largest fire on record, scorched 430,000 acres and hundreds of homes in Butte and Tehama counties in late July and August. Some of those acres were in the Big Chico Creek Ecological Reserve, on which Hankins has conducted planned burns since 2009, intentionally lighting fires to clear vegetation and encourage native plant growth.

The reserve was perhaps as prepared as anywhere else in the area. And yet, when Don Hankins first saw it, trees burned down to matchsticks, a canyon scorched on both sides, an 1870s barn where classes and community events gathered reduced to rubble, he was surprised at how much damage the fire left behind. It felt like a punch to the gut.

“Initially, I thought, ‘Wow, was the work that had gone into it, was it all in vain?’”

As he looked around at the fresh growth of native grasses, flowers and trees and saw instead success: a land that bounced back despite experiencing an extreme wildfire. There are areas where the fire calmed down, thanks to the burning he and his colleagues did. And if the rest of the watershed had been prepared in the same way, the entire fire would likely have been much less intense.

“It’s really a testament to the work that we’re doing here,” he said. “All this regrowth right off the cuff. It’s a real gem to be able to share with people.”

Prior to Spanish settlement, millions of acres a year burned in California, some fires ignited by lightning strikes, others by the indigenous inhabitants. Native people set these fires for scores of purposes, from reducing insect populations to encouraging the regrowth of basketry materials. However, one clear effect was that the more young trees, shrubs and grass were burned, the less fuel there was for future fires. In the hopes of bringing back some of that old-style fire protection, land agencies said they want to dramatically increase the use of prescribed fire.

They have been slow to implement on a scale big enough to curb out-of-control wildfires. That’s true around the state, but Butte County has been especially hard hit by recent fires, including the Dixie, North Complex and Camp Fire, which destroyed the town of Paradise. And even when the land has recently burned in a planned fire, as it was at Big Chico Creek, mild wildfire is not a guarantee: topography and weather also get a vote in how a fire behaves.

“There’s places on the landscape where we know fire likes to flow. It’s kind of like water,” said wildfire mapping expert and analyst Zeke Lunder. Lunder is also a trained “burn boss,” qualified to run prescribed burns. “It flows over the landscape in kind of knowable ways.”

Hankins pointed to a field dotted with burned oak trees, sloping down toward a creek. Look at the ash and soil, he said, the color of which indicates how hot the fire was.

“We see areas here and there with red soil and white ash,” he said. That tells us it was really hot in those places. His research has shown that, as those areas recover, often “native plants are the only things that have survived deeper down in the seed bank.”

“We’re going to have a lot of native plants that maybe we haven’t seen in a few generations out here in those places,” Hankins said. “I’m really looking forward to that.”

In other patches, where ash is black, the fire burned less intensively. Perhaps ironically, that may lead to a longer-term recovery in those areas and more work for the 40 or so employees who take care of the reserve.

“Because of the timing of the fire, we’re probably going to have a lot of our invasive grasses and plants, like yellow star thistle, will come back mixed in with our native plants,” he said. If it had swept through in fall instead of summer, on the other hand, it would have likely favored natives over invasives. “Our ultimate stewardship out here is really focused on trying to get native plants to dominate again in the landscape.”

These effects run counter to the conventional, simple wisdom that hot fire is ecologically bad and low-intensity fire is ecologically good. Hankins stressed the situation and place are important when talking about fire. Here, the reserve is in the foothills of California’s Cascade Range and nonnative species abound. He has seen high-severity fires in other locations, such as at higher elevations in the mountains, which can be very harmful to native species. Fire is complex—and the thing about complexity is that it’s complicated.

But there is also good news all around.

In a meadow that gets burned every year, there is an early “green up” of native plants: blue wild rye, creeping wild rye and—California’s state grass—purple needle grass. The oaks all around are already greening, new sprouts shooting from their trunks or branches.

“This landscape evolved with fire. The structures that were here are just temporary,” Hankins said. “The only real guarantee we have is that fire is going to be here. So the real opportunity for us is to decide, what kind of fire do we want here?”

Imagine, he said, if there had been a checkerboard of burns in the footprint of the fire, if the tops of the ridges had been tended and prepared.

“That would have slowed, maybe even stopped the progression of this fire. But there was none of that.”