Logging Safety: A Field Guide
Section Four: Limbing and Bucking
Limbing is cutting branches off felled or standing trees. Bucking is sawing felled trees into sections called logs.
- Many loggers are hurt and sometimes killed during limbing and bucking operations.
- Never limb a tree just after felling; allow more time for overhead hazards to come down before limbing.
- Felled trees often have a great amount of stored energy in their limbs and stems.
- Loggers must release this energy in a controlled manner.
- Limb and buck on the uphill side of each tree or log, where rolling or sliding of logs may be expected.
- Chock or move logs to stable positions to prevent the logs or the butt from striking loggers.
- Do not cut above the level of your shoulder when limbing.
Check for potential hazards:
- Look for overhead hazards such as hanging limbs and rolling trees.
- Check for spring poles.
- Look for butt movement forward (creates back pressure on limbs).
- Look for butt twist (creates sideways pressure on limbs).
- Check if the butt is off the ground (creates tension and compression on the tree stem).
Check for potential hazards:
- Look for steep terrain and rolling trees (see below).
- Relieve tension for top bind and bottom bind.
- Use tongue and groove cuts if there is danger of tree or part of tree rolling on the logger.
- The stem of the tree is first bored in the center.
- Up and down cuts are made either closer to the top or butt of the tree.
- Each cut must bypass the bore cut but do not meet.
- With all fiber severed, the tongue and groove will prevent tree from rolling.
- Safest way to release a spring pole is to shave a sufficient amount of wood from the underside to allow the wood fiber on the top to release slowly.
- To find the best point to shave or release spring pole:
- Determine straight vertical line up from stump.
- Find where it meets a horizontal line from highest point of the bend.
- Come down at 45 degree angle from where two lines intersect.
Butt Movement Forward: Butt Twist
Back and Sideways Pressure on Limbs
- Limbs with back pressure can severely injure a logger. Use a limb lock to prevent injury. The limb lock prevents a limb under pressure from kicking back and striking the logger or pinching the saw.
- Make the first cut on either top side or bottom side of limb (top and bottom refer to limb position as if the tree were standing up) on the side with compression pressure.
- Make the top cut on the limb closer to the trunk.
- Make the bottom cut further out on the limb.
- Make sure the two cuts bypass to sever all fiber.
Butt off the Ground:
Tension and Compression on the Stem
- Twisting of trees and butts off the ground create pressure on stem.
- Use a top lock to prevent the top from kicking up.
- Make the first cut on side of tree under compression, in the top or bottom of the stem.
- Make the second cut on the side under tension to prevent pinching the saw.
- Make the top cut closer to the top of the tree and bottom cut closer to the bottom.
- Both cuts must bypass so that all fiber is severed.
- Arrows show saw travel.
- Center is heartwood that will break.
- May want to use end of the bar to bore from point "C" to make cuts (1) & (3), if there is danger of log slabbing (lateral split of a log).
- Note: If the top bind is excessive, a wedge section could be removed to allow the tree cut to close as cuts (4) and (5) are made.
- Cuts similar to top bind, except top and bottom cuts are reversed.
Limbing and Bucking Checklist
- Are there any overhead hazards?
- Have any spring poles been created?
- If so, will they be mechanically released or released by properly shaving wood from the underside?
- Are you planning on limbing and bucking on the uphill side of the log?
- Will the log move or roll?
- If so, have you chocked the log or planned to use cuts such as the top lock or tongue and groove to control log movement?
- If you are bucking a wind-thrown tree, have you chocked the root wad to prevent it from hitting you?