Arborists work to preserve McBaine bur oak tree

COLUMBIA — A tiny twig of a tree sticks out from the ground, wrapped with elastic, giant leaves dwarfing its thin trunk.  

A few yards away, another sapling stands 3 feet tall, with a trunk the width of a half-dollar and an odd ridge halfway up the tree.

Thirteen miles south, a 20-foot-tall tree has produced a few acorns to drop on John Sam Williamson Jr.’s front yard.

All of these trees come from the same place: the branches of the 90-foot-tall state champion bur oak tree. But these plants aren’t the McBaine bur oak’s offspring; they are exact copies. Tree specialists from Columbia and other cities, including Jacksonville, Ill., are trying to preserve the giant tree.

In March 2008, several MU professors and area agroforestry experts undertook the task of sprucing up the McBaine oak tree. The team tried to eliminate much of the tree’s dead branches. They loosened the dirt around the roots and spread fertilizer. The group also put a growth retardant in the soil. This chemical will encourage the tree to produce more leaves instead of growing taller, which should make the tree healthier.  

But the process that got most of the group excited was pruning tiny twigs off of the ends of the branches. These twigs, called scion, soon became tiny clones of the McBaine oak tree through a process called grafting.  

“Basically, the purpose of grafting that tree was to preserve it,” said Ryan Russell of MU Landscape Services. Russell took more scion from the McBaine oak this spring.  

To graft a tree, he took this year’s growth for scion and attached it to a rootstock, or a different planted seedling, usually another oak.  

“If you’re good at what you’re doing,” Russell said, “the root will push all of the growth into that little piece of scion wood.” This results in an exact genetic copy of the original tree.  

Earl Cully, owner of Heritage Trees in Jacksonville, Ill., helped with the grafting process in 2008 and considers himself an expert in grafting oaks.  

“It’s a long process,” Cully said. “It’s not something you can crank out in one or two years. The grafts might not get as big as the original, but they should grow just like the parent tree. I would expect that they’d live just as long, however long that might be.”

The current grafts are spread around the area. MU plant sciences professor Christopher Starbuck has one in a greenhouse at MU, Russell has a few tiny grafts in Columbia, and Cully has two from last year.  

“I just wanted to graft and save that genetic gene pool,” Cully said. “I want to get one planted in my arboretum, and the others, I think, should be planted somewhere over in Missouri.”

Russell said some of the grafts could be planted at MU, and others could be donated to various organizations or planted on private property.

Various other copies have been passed around the group that helped prune the tree originally.

“If something were ever to happen to that old tree, we’d have some floating around,” Russell said.

Williamson, who owns the McBaine oak, also has an older graft of the tree in his front yard. Williamson was happy to see the original tree trimmed, grafted and pampered because it’s part of his family history.

“It’s kind of a historic landmark,” he said. “College students and people from the university have been coming down here to look at it all my life. My dad, who was born in 1902, remembered it as a big tree. It’s obviously genetically superior, but it’s also lucky.”  

The MU Forestry Club bore a hole into the tree in the 1950s and counted the rings from the sample, Williamson said. They estimated the tree to be about 300 years old, so Williamson now considers it 350 years old and in good health, despite the fact that the McBaine oak has been struck by lightning several times and was surrounded by 6 feet of water for six weeks during floods in 1993.  

“Trees don’t really heal like humans,” Russell said. “They just seal off the wound and form calluses, which stops it from decaying any further. This year, I went back and checked it, and it seems to be healing quite well.”  

Russell was surprised to see more than half an inch of callus wood over the cuts where limbs had been trimmed away last year — something that usually takes years.  

The tree has an official circumference of 287 inches and is 90 feet tall with a limb spread of 130 feet, according to the National Register of Big Trees. It has been the Missouri Champion bur oak for 22 years, Williamson said, and it is the national co-champion, tied with a tree in Woodford, Ky.  

However, Russell is concerned about the damage done by motorists who drive under and around the tree, tamping down soil and injuring the root system. 

“People go driving around it or mudding through the area,” Russell said. “That’s what killed part of the root system. Most of the dead wood on the tree was on the side that people parked on.”

Williamson said that though many visitors take care of the tree, others sometimes leave trash behind.

“I’m happy for people to visit and have picnics,” Williamson said. “But I wish they wouldn’t drive around it. Many of them don’t realize they’re harming the tree; they just drive around it enjoying the shade.”

Williamson has thought about building a fence around the tree but decided that any obstruction would take away from the McBaine oak’s beauty.