The KNP Complex that burned along the Generals Highway in Sequoia National Park, along with drought and disease, has left thousands of "hazard trees" that pose a threat to people and infrastructure/Inciweb

Thousands of trees of all species along the Generals Highway in Sequoia National Park pose risks to park visitors and structures because of their weakened condition due to the wildfire burning through the park as well as disease and the region's long-running drought.

Exactly how many trees need to be taken down and removed, or simply trimmed to address hazardous conditions, remains to be seen. An initial estimate of 10,000 trees was made from observations along the Generals Highway from Grant Grove in Kings Canyon National Park down towards Lodgepole in Sequoia.

"Just that section of the Generals Highway is what we're talking about when we come up with this number of approximately 10,000 hazard trees," Sequoia spokesperson Rebecca Patterson said Sunday during a phone call. For the rest of the highway that runs on south past the Giant Forest and down to the park's Ash Mountain Entrance, "we don't even have preliminary numbers for that area," she said.

While some media reports said there were 10,000 sequoia trees that were considered hazardous, Kimberly Kaschalk, a spokesperson for the massive KNP Wildfire Complex, and Patterson both clarified that a number of species were involved in the estimate.

"This is a whole different mishmash of different types of trees," Kaschalk said of the situation along the Generals Highway. "We have incense cedar, there's different types of pine, it's just in the entire forest, not just sequoia groves, and it's not necessarily sequoia trees. They're assessing all of the trees in the burn areas to see which ones need to be taken down, which just need a little trimming and maintenance. ... The last thing they want is for a tree to come down and either block the road completely and strand people or heaven forbid hit someone.

"It's not 10,000 sequoia trees, it's not even 10,000 are going to be cut," she stressed. "What they need to do is mitigate those, and it doesn't necessarily mean they're going to clear-cut them, they may just need 'trimmed up,' like branches trimmed off or just some some general maintenance just to keep these trees from falling."

A BAER team -- Burned Area Emergency Response -- is to spend the next two weeks in Sequoia National Park assessing and gathering information within the burn perimeter to gauge threats to humans and structures, as well as to assess how best to stabilize and reduce negative impacts to natural resources.

"The BAER team’s specialists will assess the effects of the fire on infrastructure, soils, the watershed, fish and wildlife, and vegetation," a park release said Saturday. "The team will then analyze this information and put together a final report with proposals about how to mitigate the damage. This report will be turned over to the park leadership, who will then work to implement the proposals."

Already there are "saw crews" at work along the Generals Highway to create safe travel zones for firefighters, residents, and future visitors. More progress needs to be made along the highway and other major routes in the fire area before they will reopen to the public.

The KNP Complex has touched the Generals Highway throughout Sequoia National Park/Inciweb

The world-renowned sequoia trees in the national park's Giant Forest were spared from the flames thanks to years of work by the National Park Service to reduce fuel loads in the area, and to firefighters' efforts to keep the KNP Complex from sweeping into the grove of sequoias that stands tall between the Marble and Middle forks of the Kaweah River. 

It is the largest of the unlogged giant sequoia groves, and it contains more exceptionally large sequoias than any other grove. It hosts the largest living sequoia, the General Sherman Tree. In this grove, visitors can see the effects of decades of prescribed burning: open forest conditions and clumps of giant sequoia seedlings that establish after fire. -- Sequoia National Park.

While the 88,307-acre KNP wildfire, which erupted from lightning strikes on September 10, was estimated to have containment lines drawn around 60 percent of the blaze as of Sunday morning, a significant change in the weather could give firefighters a hand.

Kaschalk said the forecast called for a 20 percent change of rain in the area Sunday afternoon, "and then tomorrow night and into Tuesday they're looking at getting the heavier rains. We're hearing anything from two inches, and then in some of the higher elevations maybe as much as five inches. They call it an atmospheric river, a narrow band of moisture that's moving in, so we're hoping that we get the right amount and that we don't get too much water all at once."

Too much rain on a burned area could lead to mudslides, as there's no vegetation left to hold the soil in place under heavy rains. The BAER team will be looking for areas that could slide under heavy precipitation, said Kaschalk.

Patterson couldn't say Sunday when Sequoia might reopen to the public, though it's not likely before December.

"If you look at the map of the current footprint of of the KNP Complex, you can see that there's fire adjacent to the Generals Highway for the majority of the length of the Generals Highway," she explained. "Almost the entire road, our main artery through the park, has been affected on at least one side by the complex. So hazard trees along that corridor are definitely going to be a significant consideration as we move towards a more complete reopening."

As the BAER team completes its reconnaissance of the burned areas in Sequoia, it will come away with a portrait of how the park's majestic sequoia groves fared. Across the park there are 34 sequoia groves, Patterson said, and the fire touched about half of them to varying degrees. She said some of the tall trees were "torched," in which the flames raced all the way up the trunks and practically explode into the trees' canopies.

"The fires got through 16 (groves), but as far as how much damage has been done, we really don't know," she said. "There's some areas where we have seen some evidence that there was high severity burning, and there's probably going to be tree mortality in those areas. And there are other places where it burned through at really low to moderate intensity, which is actually very healthy for growth. So we're expecting to see a real range of effects out there."