More than three years after a wildfire devastated Big Basin Redwoods State Park in the Santa Cruz Mountains, the massive redwood trees in California’s oldest state park continue to recover with surprising speed.

But some wildlife species, particularly salmon and steelhead trout in the park’s streams, and some types of birds, are still struggling and could take many years to bounce back.

That was the conclusion of researchers who spoke at a recent scientific symposium exploring how Big Basin is faring in the wake of the 2020 CZU Lightning Complex Fire.

The best news: The park’s famed old-growth redwoods, some of which tower more than 250 feet and date back more than 1,500 years, are nearly all green again, showing significant amounts of new growth after the wildfire’s flames charred their bark black and for a while gave them a doomed appearance.

“Coast redwoods are just supremely fire adapted, and were well-prepared for this fire event, and they seem to be recovering, at least so far,” said biologist Drew Peltier, an assistant professor at the University of Nevada Las Vegas, who has studied Big Basin’s post-fire recovery.

At the symposium, hosted Wednesday by the nonprofit Santa Cruz Mountains Bioregional Council, Peltier explained how eight months after the fire, he and other researchers from Northern Arizona University set up a camera high in a redwood tree about 1 mile from park headquarters to automatically take photos every day.

The first photo he showed, from April 2021, revealed a forest dominated by brown, burned redwoods. The next photo, taken this past June, showed the same forest covered in green, the trees regrown thick in only two years.

“What we saw was pretty remarkable. All these trees are brown, they have no green foliage,” Peltier said of the first photo. “And two years later, they are fully leafed out. I pulled the image from today and I almost didn’t recognize it. The trees are so bushy now.”

The fire started with lightning strikes on Aug. 16, 2020. It burned 86,509 acres, an area nearly three times the size of the city of San Francisco, in rural Santa Cruz and San Mateo counties. Flames from the most destructive fire in the Santa Cruz Mountains in recorded history destroyed 1,490 structures, mostly around the town of Boulder Creek. One man was killed.

The fire burned 97% of Big Basin’s 18,000 acres. It destroyed campgrounds, the park’s iconic 1930s-era headquarters building, its outdoor amphitheater, museum, gift shops, ranger homes and dozens of wooden bridges — many of which were facilities loved by generations of families, including the 1 million people a year who visited.

“Ecologically, the park is doing just fine,” said Jon Keeley, a senior scientist at the U.S. Geological Survey and biology professor at UCLA who participated in the symposium, in an interview afterward. “The forest is coming back the way it is adapted to. About 90% of the redwood trees are resprouting.”

Keeley said Big Basin’s forests are recovering faster than the buildings and other visitor amenities.

State parks officials have reopened the park, but in a limited way. Visitors are required to make day-use reservations. There is no camping. But 4 miles of trails and 18 miles of fire roads have reopened for hiking and mountain biking. Earlier this month, a welcome center at Rancho Del Oso, on the park’s southern edge near Highway 1 and the Pacific Ocean, also reopened.

State parks officials have held public meetings and focus groups to draw up plans to rebuild. Their vision includes moving some of the buildings, camping and parking away from the most sensitive old-growth redwoods in the former headquarters area, and putting them in other parts of the park, including at Little Basin, a property on the park’s eastern flank. A shuttle bus system also is being designed for visitors in busy times, reducing traffic.

Will Fourt, a senior state parks planner, told the symposium that a more detailed “facilities management plan” with specifics about new campgrounds, utilities, parking and buildings is now being drawn up by state parks officials and will be released to the public next year. Construction is still several years away, he said, adding that the goal is to rebuild about the same number of campsites as were there before the fire.

“The vision includes rebuilding some things differently than they were in the past,” Fourt said, “while honoring the history of the park and striving to create future trails and camping experiences in the park that were most important to visitors.”

One part of the park that is still struggling is its streams and fish.

Jerry Smith, a professor emeritus at San Jose State University who has studied the parks’ fish for 30 years, said that parts of Waddell Creek were filled with sediment when big storms this winter and the winter before sent mud, rocks and other debris washing down from bare slopes along the park’s western edges. Some dead trees, including Douglas firs, created logjams in the creek and its tributaries.

The changes have likely blocked the passage of endangered steelhead trout and coho salmon, and filled in many of the pools that the fish rely on. In one area of Waddell Creek, he said, “you’ve got a logjam as big as a football field.”

As a result, coho and steelhead have been almost nonexistent in Waddell Creek over the past two years, he said. After similar disruption following huge storms in the winter of 1982-83, it took the fish 15 to 20 years to recover, he said.

Until more vegetation grows on the steep western slopes of the park, another wet winter this year will continue the destructive trend.

“Waddell got really hammered and is going to continue to get hammered,” Smith said.

The park’s bird species have seen a mixed recovery. Biologist Alex Rinkert told the symposium that his surveys have found three years later some species, including woodpeckers, robins, juncos and warblers, are back in healthy numbers, while others such as jays and chickadees have declined, due to the change in habitat and possibly food sources after the fire.

A few species, like the endangered marbled murrelet, which lives in the Douglas fir trees that were killed in large numbers, have declined significantly “and may take decades to recover,” Rinkert said.