Notching and Backcutting

the professional longer felling timber in the woods has two main concerns safety and efficiency directional felling through proper notching and back cutting techniques is the key to both of these concerns directional felling means that the cutter is at all times in complete control the timber he is cutting it means that the feller and his crew are protected from the hazards of timber falling out of control and it means an orderly felling pattern that allows faster easier and safer lemming and skinning in this program we will examine the three basic types of Nod the back cut and the hinge and the boxing and back cutting techniques that add up to safety and efficiency in directional felling the first step in felling any tree is to assess the tree the area and the escape route factors to consider include the natural lean of the tree any heavy branches on one side that could affect direction of fall snow or ice loading the wind direction and speed branches that are bound in with the neighboring trees other trees or ground obstacles to avoid hitting and of course the skidding pattern itself a good work area with solid footing clear of underbrush branches and debris is needed this means cutting small saplings low and flat to the ground to reduce tripping hazards and prevent damage to skidder tires he escape route the safest direction for the cutter to retreat extends back and away from the tree at a 45 degree angle it must be brushed out and ready for use when the tree starts it fall there are basically three types of knotch that will be discussed in this program the conventional not the undercut or humble notch and the v-notch each of these notches is best suited for use under certain conditions but all three work on precisely the same principle each notching system consists of three basic parts the notch itself cut in the exact direction of intended fall the back cut or felling cut that allows the tree to fall and the hinge the strip of uncut wood between the notch and the back cut that holds the terrain position so that it falls under control in the intended direction of fall the function of the notch is to allow the tree to fall in the intended direction before binding on the stump as the tree falls the trunk and the stump fall together like a miter joint when they fold together the hinge is broken and the tree continues to fall to the ground the back cut made directly opposite and one to two inches above the notch sever's enough of the remaining wood fibres to allow the tree to fall the hinge or the uncut holding wood between the notch and the back cut holds the terrain position while falls in the direction of the notch the first step in the felling process then is to choose a target in the desired direction of fall where possible the knot should be from the right side of the tree if the left shoulder is placed against the tree and the body position behind the saw the sighting lines on the saw can be aimed exactly at the selected target properly positioning the notch is very important even a fraction of an inch off line at the stump can mean that the top of the tree will miss the target by several feet the first type of knots that we will look at is the conventional knotch it is the knotch most commonly used and is the simplest to make it should be made with the left hand on the corner of the forward handle of the saw so that the first cut is made sloping downwards at an angle of about 45 degrees it should extend to a depth of about one third of the trees diameter the depth of any knotch should be about one third of the diameter of the tree but can vary from one quarter to one half depending on the circumstances the width of the knot should be as wide as it is deep or 45 degrees to ensure that the hinge wood doesn't break until the tree is committed to falling in the desired direction if the notch is not properly positioned the tree cannot be expected to fall where intended once this cut is made the cutter can look down at it while making the second cut straight and level both Koch should then meet cleanly and on completion of this second cut the wedge of wood should come clear of the tree the mouth of the opening will be roughly equal to its depth before leaving the knotch it should be examined to ensure that both cuts meet cleanly the direction of the notch can also be verified by placing the bar of the saw into the notch and using the sighting lines to confirm that it is lined up with the target the back cut is again made directly opposite the notch it should be level and one to two inches above the notch it severs enough of the remaining wood fibers to allow the tree to fall since the sloping cut of the notch is made on the trunk of the tree the falling tree may tend to ride up on the stump and slide back towards the cutter the back cut placed above the notch creates a ledge or a step to hold the butt and prevent it from sliding back you should stop cutting the back cut when the tree begins to fall or the proper amount of hinge wood is left in some cases perfectly balanced trees may require a felling wedge the humble knotch is essentially a reverse of a conventional knot the first cut is made sloping upwards into the trunk at a 45 degree angle to a depth equal to about one-third the diameter of the tree the second cut is made level to meet the first cut cleanly the back cut is made and each or - higher than the level cut of the notch the humble gaucho has several advantages first it's safer than the conventional notch with the sloping part of the notch cut into the stump the falling tree will tend not to kick back at the cutter part of the stump is cut into a ramp and the butt of the falling tree will slide down and away secondly the Humboldt causes the falling tree to slide down and land clear of the stump where it's safer and easier to work with and third it is more economical and produces a better quality log simply by cutting the notch out of the stump rather than out of the butt of the log on some of the larger diameter saw and veneer logs the difference in value can be very significant if that first butt log is downgraded due to the removal of the notch material the Lee notch is used for felling larger diameter trees on steep slopes when the falling tree will fall downhill and swing past the horizontal before severing the hinge the v-notch is made with two sloping cuts one sloping downwards the other up the two cots should meet cleanly one-third of the way into the tree and the knots will have a monk much wider than its death the back cut again straight and level is made an inch or two above the back of the notch this knotch gives the tree a larger opening to close as it falls so that the hinge is not broken until the tree falls past the horizontal some trees especially the larger diameter hardwoods and those with a pronounced flair require an additional step in the felling process cornering cuts these cuts are made to a depth of an inch or two at the leading edge of the notch on both sides of the tree they're flat and at an angle of about 45 degrees to the direction of fall cornering cuts are designed to sever the strong SAP wood fibres at the outside of the tree to prevent side scarring and damage to the butt of the trunk all three notches have one more thing in common the hinge it's the hinge that provides control and it's the hinge not the notch that ultimately determines the direction of fall a tree with a properly aimed notch but without a hinge could fall in any direction depending on lean weight distribution or wind speed and direction the hinge is a solid strip of wood that should be about a tenth of the diameter of the tree that is left between the notch and the back cut a hinge on a door allows the door to swing in two directions only open and shut similarly the hinge on the tree allows the tree to move in two directions only forward into the notch or straight back if there is insufficient lien or weight in the desired direction of fall a felling wedge is used to prevent the tree from sitting back as the tree starts its fall begins keeps it from any sideways motion until the tree is committed to falling forward there is one hazard that is common to all three types of knotch over cut notches an over cut notch is made when the cutter overshoots one of the cuts of the notch it means that the two notching cuts do not meet cleanly and that one saw cut extends beyond the notch into the tree when a tree with over cut not starts to fall it closes the overshot saw cut first and as the trunk contacts the stump it's fall is momentarily interrupted the tree hesitates in its fall and a great strain can build up the tree could break the hinge off permanently and fall out of control it might split up the middle in a barber chair or it might pull fibres from deep within the trunk before falling all three possibilities place the cutter at risk from an unpredictable fall and all three situations also mean dollar loss when a tree is downgraded due to over cut knotch damage the time to correct the over cut notch is immediately after the notch is made a single saw cut to enlarge the notch and meet the under or over cut saw cut eliminates the hazard the stumps in the butt-ends of felled trees leave a permanent record of every cut and show clearly how the felling was done it shows whether a proper notch was used if the back cut was leveling high enough if appropriate hinge wood was left and if an over cut notch was made checking stumps is a good way for the cutter to assess his own work and identify any areas that require improvement as a professional logger felling timber you have two main concerns the safety of yourself and your co-workers and the value and efficiency of your work proper notching and back cutting techniques allow you to achieve both of those goals every part of the felling operation fits together to make the job safe and efficient you

Channel: Workplace Safety North

Views: 398,447

Keywords: WSN, Occupational Health and Safety, Workplace Safety North, Health and Safety, Workplace safety, Ontario, Forestry, Felling site hazards, Fell trees safely, Felling process, Chainsaw, Chain saw, Chain, Saw, Notching, Backcutting, Notch, Felling trees safely, Cut down trees safely, Cut down trees, Logging, Conventional logging

Id: I8YstkyBsRQ

Length: 14min 6sec (846 seconds)

Published: Tue Jan 22 2013