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Bark-Scoring Tools to Repair Tree Grafts
The field evaluation took place on the Rogue River National Forest. The basic premise was that people who did bark scoring operationally could best decide which was the optimal tool(s). Hal Miller and Ron Colton evaluated the bark-scoring tools at a Douglas-fir seed orchard on a broad diameter-range of trees. Factors such as bark thickness, swelling on tree bole in the grafted area, and tenderness of the bark on younger trees influenced their final recommendations. Most of the tools were weeded out quickly. Damage to trees or poor tool ergonomics was the usual reason. Occasionally a tool guard had to be revamped by MTDC’s shop to allow for more efficient operation. Questions about the field evaluation can be answered by calling Hal Miller at 541–858–2329, or sending E-mail to: hnmiller@fs.fed.us.
Cordless Circular Saw—Some grafted Douglas-fir trees have a large swollen area at the graft union. The circular saw did not do a good job of creating a cut that was deep or uniform enough. Also, the standard saw blades were too narrow. Larger cordless circular saws are heavy and are hindered by lower tree limbs. This type of tool was dropped from further consideration.
Cordless Right-Angle Drill—The field evaluators said the Percival cutter design worked but was not their first choice. The Whiteside and Arbortech cutter designs were not intended to operate at the right-angle drill’s slow speeds and bounced around, damaging the tree. The right-angle drill was somewhat awkward to operate. The tool was dropped from further consideration.
Small Cordless Chain Saws—For scoring trees in the 1- to 8-inch-diameter class, the field evaluators preferred the cordless Makita chain saw fitted with MTDC’s chain guard. This tool was very well balanced and had a comfortable handle. A Job Hazard Analysis was written stressing operational techniques that minimized the possibility of kickback. This was the only tool that was tested over an extended period of time. The saw cut about 180 trees (5- to 6-inch d.b.h.) with two fully charged batteries during a full 8-hour day. The operator reported no fatigue. All work was fast and efficient with very clean cuts. Clean cuts heal much faster than those made by a gasoline-powered chain saw that throws petroleum-based chain oil into the cut.
The cordless chain saw from China does not feel as well balanced as the Makita saw. It also comes with a different chain (figure 12) that only has one raker behind the cutter tooth as opposed to the two rakers the Makita chain has behind the cutter tooth. The evaluators thought the Makita saw made a cleaner cut than the saw from China. Because of battery problems with the saw from China, no extended time-motion data were collected.
![[photo] Chain saw chains](images/fig12.jpg)
Figure 12—Cordless chain saw chains. The Makita chain on the left
has two rakers for every cutter rather than one.
Cordless Rotary Tool—The Wizard produced a precision cut when scoring very-small-diameter stems (figure 13). This tool was very well balanced.
![[photo] Wizard cordless rotary tool making small cuts on a branch](images/fig13.jpg)
Figure 13—The Wizard made precision cuts on small branches.
The best all-around tool for tree scoring was the Makita cordless chain saw with MTDC bar modifications. For very-small-diameter stems (1 inch or smaller), the Black& Decker Wizard with rotary cutter or 2-inch-diameter Arbortech woodcarving blade is a good choice. In addition to locating useful commercially available tools, MTDC has developed modifications for these tools that should make them safer and more efficient for bark scoring. The guards were modified based on comments from the field evaluators. Engineering drawings of the modifications are available over the Forest Service’s internal computer network at http://fsweb.mtdc.wo.fs.fed.us/dwf/index.htm or as hard-copy drawings upon request. As these tools continue to be used, additional modification requests may come in from the field. If they do, MTDC will tackle them with Nursery Tech Services funding. This project is now formally terminated.
The next five items are all available from the source following them.
Keith Windell is a Project Leader for reforestation, fire and residues projects. He has a bachelor of science degree in mechanical engineering from Montana State University, as well as an extensive field background. He has worked for the California Department of Forestry, Bureau of Land Management, and the Forest Service.
Phone: 406–329–3956
Fax: 406–329–3719
E-mail: kwindell@fs.fed.us
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