THREE RIVERS, Calif. — Upwards of 10,000 sequoia trees weakened by wildfires, drought, disease or age must be removed in California, work that will keep a nearby highway closed to visitors who seek the world’s two largest sequoia trees.

The hazard trees could potentially fall onto people and cars on the section of State Route 180 known as Generals Highway, or they could create barriers for emergency and fire response, the Sequoia and Kings Canyon national parks said Friday.

The highway is closed due to the KNP Complex blaze, which was 60% contained after burning 138 square miles of forest, and will remain blocked off to visitors after the fire is out while crews remove the trees. Cooler weather has helped slow the flames and the area was expected to see rain starting Sunday.

The highway connects Giant Forest, home to the General Sherman Tree, which is considered the world’s largest by volume, and Grant Grove, home to the General Grant Tree, the second-largest tree in the world. The trees along the highway include sequoias, pine and conifer trees, said fire spokeswoman Kimberly Caschalk.

Forest officials said earlier this month the lightning-caused fires may have killed hundreds of giant sequoias, but the full extent of the damage has not been determined.

The fire’s impact on giant sequoia groves was mixed. Most saw low- to medium-intensity fire behavior that the sequoias have evolved to survive, and the most notable trees survived.

Firefighters took extraordinary measures to protect the sequoias by wrapping fire-resistant material around the bases of some giants, raking and clearing vegetation around them, installing sprinklers and dousing some with water or fire retardant gel.

On Friday, forest staff unwrapped the base of the General Sherman tree after danger from the fire had passed.

“We’re confident that tree is relatively safe,” Caschalk said.