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Special Techniques for Felling Difficult Trees

Using wedges to fell a tree against its natual lean.   A large tree may be felled against its natural lean by inserting one or more wedges in the back cut. As the back cut is sawn, the wedges are driven in with an axe.

The amount of back lean that can be overcome is based on the height and diameter of the tree to be felled. The following methods determines the amount of back lean which can be overcome with 2 inches of wedging.
 

Wedging Trees with Back Lean
Trees That Side Scar Easily
Felling Larger Trees
Heavy Forward Leaners
 
The following are unacceptable practices: Wedging Trees with Back Lean
  • Determine the height of the tree. This can be estimated quite accurately using one of these methods:
    • Pro-Sight method
    • Clinometer method
    • Axe handle method
  • Determine the diameter (not circumference) of the tree at breast height using a tape.
  • Determine the number of segments in the tree by dividing the height (in feet) by the diameter (in feet).
    • Example: a 100 foot tree 24 inches in diameter (2 feet) would yield 50 segments (100 2).
    • Example: a 100 foot tree 12 inches in diameter (1 foot) would yield 100 segments (100 1).
  • Determine the amount of back lean (in feet) by plumbing the tree.
Trees That Side Scar Easily
 
In standard felling, the sides of the hinge between the notch and the back cut are not sawn when the tree starts to fall.
 
  1. In standard felling, the sides of the hinge between the notch and the back cut are not sawn when the tree starts to fall.
As the tree falls, there is strain on the sides of the tree along the dotted lines.
 
  2. As the tree falls, there is strain on the sides of the tree along the dotted lines. (circled area)
Instead of breaking with the hinge, strips along the side of the tree rip off the stump, resulting in side scars.
 
  3. Instead of breaking with the hinge, strips along the side of the tree rip off the stump, resulting in side scars.
To prevent side scarring, corner to a depth of one inch before making the back cut   4. To prevent side scarring, corner to a depth of one inch before making the back cut.
 
Felling Larger Trees with Slight Lean or with Heavy Tops
 
The notch is made in the normal manner (1/3 dia. of tree).
 
  The notch is made in the normal manner (1/3 dia. of tree).
Make corner cuts
 
  Make corner cuts.
The number one cut is made as per the diagram, at the same height above the notch as a standard back cut.
 
  The number one cut is made as per the diagram, at the same height above the notch as a standard back cut.
The number two cut is made as per the diagram, at the same plane as cut number one.
 
  The number two cut is made as per the diagram, at the same plane as cut number one.
The number three cut is made at the same plane as the former cuts, leaving the standard thickness of hinge.   The number three cut is made at the same plane as the former cuts, leaving the standard thickness of hinge.

Heavy Forward Leaners (The boring technique)
 
Begin by making a shallow notch (1/4 to 1/3 dia. of tree).
 
  Begin by making a shallow notch (1/4 to 1/3 dia.
of tree).
Next, holding the saw bar horizontal to the plane of the notch and at a slightly higher plane, the tree is bored out cutting back from the notch, leaving a good hinge and sufficient holding wood.
 
  Next, holding the saw bar horizontal to the plane
of the notch and at a slightly higher plane, the tree
is bored out cutting back from the notch, leaving a good hinge and sufficient holding wood.
The same boring procedure is then performed on the other side of the tree, ensuring that the two boring cuts meet properly, and leaving a strap of holding wood.
 
  The same boring procedure is then performed on
the other side of the tree, ensuring that the two boring cuts meet properly, and leaving a strap of holding wood.
Then the back strap is severed by a cut horizontal to the boring cut, one to two inches below the boring cut; the holding wood at the back severs and the tree falls, guided by the hinge.   Then the back strap is severed by a cut horizontal
to the boring cut, one to two inches below the
boring cut; the holding wood at the back severs
and the tree falls, guided by the hinge.


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