Missouri's champion bur oak — known by many simply as "the big tree" in Boone County — was seared by a lightning strike Friday morning.

Passersby shot video of the tree's nearly 24-foot circumference trunk spewing smoke from the lightning hit. Boone County firefighters quickly reached the tree and were working to extinguish the fire using foam.

At one point, firefighters cut into the tree, which appeared to be burning from inside its core.

Columbia resident Cody Spencer said he was driving when he witnessed the lightning flash in the sky.

"I was a half mile away and I saw the lightning light up the sky, but I didn't see it actually hit the tree," he said. "But when I came around the corner about a half mile away I could see that the tree had been hit. It looked like a bomb went off."

He shot video of the tree, with smoke pouring from the trunk.

"You could see flames coming out of the tree where a tree limb had been blown off," Spencer  said. "Some of the limbs were blown 50 yards away. It was like an explosion."

Before firefighters arrived, Spencer said he scooped up several handfuls of acorns from the tree.  He may try to plant them.

"There's centuries of history with this tree," he said. "I was the first one there after it happened and very shortly there were at least 100 cars showing up to see it."

The solitary tree adjacent to a road near Columbia is a statewide landmark, its branches reaching 90 feet high and 130 feet wide. It's the largest bur oak in Missouri and is tied with a tree in Kentucky as the biggest bur oak in the country.

The tree is believed to be between 350 and 400 years old. It has survived lightning strikes before and terrible wind storms that toppled another huge bur oak nearby several years ago.

Not even the disastrous flood of 1993 could drown the tree, when floodwaters reached 9 feet high on the tree's trunk. The National Park Service notes the tree was already big when Lewis and Clark set out on their westward expedition in 1803.

The tree is so well known, it even has its own Facebook page, The Big Bur Oak.

Late Friday it remained unclear if the tree would survive the lightning hit. Some observers on the scene said it appeared the tree's trunk was hollow and smoldering.