Felling: Intentionally cutting "sapwood" portion of hinge?

[Billy_Bob]

I read in a book that when felling certain types of trees, the feller will intentionally cut the sapwood portion of the hinge (leaving the heartwood portion) as with certain trees, the sapwood is so strong it will "tear" rather than break. And this causes "side-scarring" on the log.

Then in this thread from the Commercial area of this forum...
http://www.arboristsite.com/showthread.php?t=23294

The first post shows a video of a quarter cut technique on a Pine tree. And the feller cuts two shallow cuts on the sides below the face and back cuts prior to felling.

I asked what these cuts were for and the 47th post said they were "Relief cuts" and "The cuts will allow the tree to break off clean if it tries to peel down the side of the stump."

Anyone know when this should be used or anyone know about any of this?

In the video he said he was doing this because it was a pine tree. Is there something about pine trees which is different than say a Douglas fir tree?

How can you tell the sapwood will "tear" rather than "break" on a certain tree?

 

[joesawer]

Imo the relief cuts in that video where totally uneeded and served no purpose.
Cutting the sap wood is sometimes needed on large valubale logs.
The thing that cannot be over emphasized is the need to preserve the corners of your hinge.
If you start cutting large volumes of hi-dollar saw logs you will soon see when you need to nip the sap wood. Until then stick with the basics and get them down.

 

[smokechase II]

Correct

"Imo the relief cuts in that video where totally unneeded and served no purpose.
Cutting the sap wood is sometimes needed on large valuable logs.
The thing that cannot be over emphasized is the need to preserve the corners of your hinge."

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This gets complex but a couple other thoughts are:
1) It can be important to nip the hinge at the corners to reduce barber chair risk, (among other cuts to help with that reduction).
2) Often the tear out will go down the stump and not up the log. No loss of fiber for the mill at the stump. But what can happen is that the tree can be powerfully taken away from the face direction by root pull. Picture one side of your hinge being directly above a large sound root and perhaps the tree has a slight lean to that side. In this case there can be a large tear out downward that will pull the tree toward that side and break up lumber by missing the intended lay and hitting obstacles. So where that is a possibility a) Think about a different lay where hinge and root/lean will not line up and b) If that option is not available consider nipping about a foot below the hinge to prevent a major root pull.

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The thing you need to remember five years from now on this thread is;"the need to preserve the corners of your hinge."


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I'll probably take some heat for this as I'm the only person I know doing this:
I'll deliberately vertically bore in about 4-6 inches deep twice (say 3-5" wide at the top and 4-8" at the bottom as low as I can cut) from the hinge area down to a major root on the side where I want to create a root pull to give something extra to take a tree further to that side. {Most of the time I do this I'll do a small holding wood nip on the off side and this will can be accompanied by a tapered hinge.} Then I'll do the back-cut up to the rear vertical cut from the other side of the tree. Details details.