As an alternative to the chemical or manual control of weedy shrubs in forest plantations, UC Davis researchers have designed and tested a new tool for mechanically removing the unwanted bushes. Though efficient, chemical spraying is often environmentally unacceptable, leaving the job of brush removal to crews armed only with chain saws and grub axes, says John Miles, a professor of agricultural engineering. To ease this task, Miles and colleagues recently developed an attachment that is much like a backhoe bucket with an additional set of clamping teeth. The attachment, which so far has been most successful when mounted on a small excavator, is designed to grab the trunk of a shrub then rock it loose from the soil. The mechanical weeding causes relatively little ground impaction, results in only minor soil disturbance, and can be accomplished without damaging existing forest trees, Miles says. He estimates the cost of the mechanical weeding at about $250 per acre, less than half the cost of manual weeding. The mechanical method is most efficient with stands of large shrubs where manual weeding is no longer feasible, he says, noting that the mechanical process could also be integrated into small landscaping businesses in foothill communities where brush removal around rural homes is crucial for fire suppression. He will discuss his work at 4:50 p.m. Thursday, Dec. 19, during a session on forest engineering research.