Instructions for the Use and Care of an Increment Borer

Foresters use increment borers to extract a core of wood from trees or freshly treated poles, pilings, lumber, or timbers. Tree cores allow you to determine growth rate, age, soundness, and penetration of wood-preserving chemicals. An increment borer is a quick and easy method of obtaining an increment core when used properly. This set of instructions will outline the safe and proper use of an increment borer.

Materials Needed WARNING: The end of the borer bit is very sharp. Handle with care.

CAUTION: If you are boring several trees, it is useful to wear gloves to prevent blisters from forming in the palm of your hands.
  • WD-40
  • Clean rags
  • Bees wax
  • Gloves
  • Increment borer
1. Figure 1.Separate the handle (A) from the borer bit (B) and extractor (C). (See Figure 1.) Place the extractor in a convenient place, such as your cruiser’s vest, to prevent damage to the extractor.
2. Assemble the handle and borer bit byFigure 2.
  1. Pushing the locking latch away from the handle with your thumb.
  2. Inserting the square end of the borer bit into the handle.
  3. Returning the locking latch completely around the borer bit "collar".

You are now ready to start boring. Figure 2 shows a completely assembled increment borer.

NOTE: Before boring a tree, apply beeswax to the threads and shank of the borer bit. This will make penetration and removal of the bit easier.

CAUTION: Never bore into a leaning tree. Leaning trees contain tension and compression wood which could cause the bit to become locked in the tree.

NOTE: The goal is to bore directly into the "pith" or center of the tree.
3. Figure 3.Align the borer bit and handle so that the bit will penetrate toward the center of the tree at a right angle. In any other alignment, the annual growth rings seen in the extracted core will be distorted and could result in erroneous growth rate analysis.
4. Figure 3a.Place the borer bit threads against the uphill side of the tree at 4.5 ft above the ground. This should be done in a fissure or crack, where the bark is thinnest. Hold the bit near the threads with one hand; with your other hand push forward on the handle while simultaneously turning it clockwise until the threads penetrate the wood enough to hold the bit firmly in place. (See Figures 3a and 3b.)
 NOTE: Do not grip the handles with closed palms, as this can result in bending the bit.
5.

Figure 4.Place both hands, palms open, on the ends of the handle and turn clockwise until the bit reaches the approximate center of the tree. (See Figure 4.)
6. Figure 5.With the bit at the desired depth, insert the full length of the extractor concave side down, like this Ç . Then turn the handle one-half turn counter-clockwise to break the core from the tree and to turn the extractor concave side up like this È . (See Figure 5.)
7.

Pull the extractor from the borer bit. (See Figure 6.) The core will be resting in the channel and held in place by the small teeth at the tip of the extractor. (See Figure 7.)

CAUTION: If the borer is left in the tree for an extended period of time, it can become stuck.

Before examining the core sample, promptly remove the borer bit from the tree by turning the handle counter-clockwise. (See Figure 8.)
8.

Figure 9.The core of wood extracted from the tree should look like the sample in Figure 9.
9. Figure 10.In order to prevent insect damage; replace the wood core into the tree once measurements and ring counts have been made. (See Figure 10.)

NOTE: A wooden dowel can be used to remove broken core pieces from the borer bit.

CAUTION: Do not use metal objects such as nails to remove lodged cores.
10.

When you are finished using your increment borer, use a WD-40 soaked cloth to remove resins from the bit. The WD-40 will also prevent rusting.

These instructions were created by Chad Bolding and Jonathan Kinard, who are seniors in Forestry at Auburn University, and have had extensive experience with the safe use and proper care of increment borers.

Date: 3/10/2000

Questions or Comments? Contact PFMT.

Most Recent Revision: 09/20/06
Private Forest Management Team
Auburn University, Alabama