Cedar Saw Used To Selectively
Control Cedar In Oak Mottes

By Colleen Schreiber

LOMETA — Evert Kirby has been operating heavy equipment since 1964. He does everything from building roads, tanks and terraces to typical brush control work, including grubbing, raking and pushing. Now he has a new invention he calls a "cedar saw."

Mounted on the front of a bulldozer, the saw slides along the top of the ground and cuts cedar without leaving a protruding stump. Kirby considers it unique in that it can selectively remove cedar that has grown up in a liveoak motte without harming the oak trees.

The idea came to him a year or so ago during the drouth. The ground was so dry that when he tried to push cedar, he says, it would snap "like an exploding cigar." It left a mess, and the rancher was never happy.

Kirby told his wife he was going to come up with an invention to cut the cedar off at ground level so a rancher could drive over it.

Kirby’s device is stationary and doesn’t operate like a mechanical saw. There’s no elasticity in it and no hydraulics, so the teeth don’t move in a circular motion like a typical powered saw. It is simply propelled forward and back by a bulldozer.

The teeth for the saw were cut out of scrap steel using a chop saw. The angled twin blades are about half an inch thick with an 8.5-inch depth of cut. Beyond the point of the blades is a spear of sorts, sharp on both edges and about two feet long; it pushes the tree over, Kirby explains, which opens it up so the cut can go in further.

The saw is attached to an 80-horse D-4 Cat. It works best on a six-way tractor, Kirby says, which provides motion to move it up and down, tilt it or angle it left or right. Two bolts mount it to the dozer blade. It takes about 10 minutes to attach and less time to drop off.

Kirby says he can cut just about any kind or size of tree, though hardwood trees naturally take more effort. He has cut trees as big as 24 inches in diameter, and it only took about two and a half minutes. In fact, Kirby says, trees that are less than four inches in diameter can basically be sawed off on the run with a single pass.

He estimates that in what he terms "medium density" cedar, his saw can clear about an acre an hour. With lighter densities he has been able to clear up to 2.66 acres an hour. Where the density is greater or trees are bigger, time and labor increase proportionately. Kirby charges a flat rate of $50 an hour.

Once, he notes, mesquite was the primary brush problem in the Central Texas area, but cedar has really encroached over the last 15 to 20 years. At first it was small, easier and much less expensive to control. Ranchers who have allowed it to expand and grow unchecked, however, may have to pay upwards of $100 an acre.

With his saw, Kirby simply cuts the cedar and sweeps it out to the drip line of the oak trees. He comes back later with a dozer blade or a rake and piles it. In addition to neatness and selectivity, he says, the saw doesn’t deface the surface and dredge up dirt and rocks.

"When contractors use a dozer blade to push cedar," Kirby explains, "most times you wind up with dirt five or six feet deep in the brush piles. Before you can burn those brush piles, you have to rake them, and that’s another operation. With the saw, I eliminate one whole operation."

Kirby says he’s never built anything without having to do a whole lot of changing, but he was pleasantly surprised how well his cedar saw worked right off the bat. He did have to change the bracing, switching to a heavier material.

The cedar saw, Kirby says, will work for any brush problem, but he’s not necessarily recommending that it be used on mesquite. It doesn’t do any good to cut mesquite off at ground level, he points out, because the bud zone is buried below the soil surface and will resprout, usually with a vengeance. To prevent that, cut mesquite stumps must be treated with oil or herbicide, and the same thing applies to redberry juniper.