Sawing the big walnut tree

very common in parts of Australia

Ian Neuhaus

especially in areas "authorised" as a source of chip wood.

I'm not sure if the defect is called "felling fracture" in Australia but the occurrence is dependent on the skill of the tree cutter.

An otherwise healthy tree can be felled in a way that turns a saw log into a chip log. In some parts, chip logs carry a premium -- in terms of reduced royalty -- over saw logs. And the premium hardwood market is much more limited in volume compared to the export wood chip market.

I believe that deliberately achieving "felling fracture" relies on the tree "smacking" the ground rather than landing more softly.

Felling fracture- still confused by this term

Bill Tindall, E.Tn.

I don't see the connection between a tree blowing over and the result splitting the tree vs putting it on the ground with a chain saw. I would presume the splitting occurred before it hit the ground and not as a result. The force on the trunk to uproot a healthy tree must be greatly more than what occurs when it thumps from a typical felling operation.

There is the phenomena of "wind shake" which often has little to do with wind. I presume we are not taking about this tree defect.

Again, I have never encountered this concern or term and remain wondering why I have never encountered the concern or term, or in fact what it typically looks like. I have seen thousands of oak logs being skidded or on log yards and never had a mill operator say something like, that would have been a dandy veneer white oak if it had not suffered "felling fracture", or some such.

The centers of oak and other trees are always "boxed out" and sold as pallet material or chipped because they are either fractured or will so in drying. I do not believe this property has anything to do with how the tree hit the ground, and everything to do with juvenile wood being different. Beyond that I only see the occasional end split that I believe is stress relief given the time scale that it occurs. These splits have little effect on log yield, quartered or not. These splits are of concern to veneer mills and they often drive devices into the end of logs to prevent these splits developing.

Redwoods are weak and can fracture when their giant mass hits the ground. Berms are created with a dozer to cushion the fall. Never seen any concern on any other tree species.

Update

Mark Mandell - Gone Round In New Jersey

Just had the arborist in. Ball-park for the crane take-down (no knuckle-boom etc.) is more than the wood is worth retail and KD'd.

Looks like we'll be dropping the tree "old style" and taking my chances that I get something out of it other than firewood.

[sigh]

Re:  Felling fracture- still confused by this term

Barry Irby

I do not have the experience Bill has, but I too have never heard of felling fracture until this thread.

Bill mentioned several terms I am familiar with. "Juvenile wood" and "boxing the heart" and "wind shakes". Juvenile wood is the early growth when the tree is "growing like a weed". In the soft wood/truss industry juvenile wood is the bane of the truss industry. This wood may have 30 times the lengthwise expansion and contraction of more mature wood. Trusses built with it may react badly to seasonal changes in moisture content and can cause the trusses to lift as much as two inches in mid-span. This wood warps badly, thus experienced sawyers box the heart and remove it as Bill mentioned. OTOH, I have seen many piles of 2x4's at big box stores that appear to be 4x4's that were resawed. And treated 4x4's are notorious for warping and twisting because the cheap ones are often the heart (juvenile wood) the sawyer boxed out of nice logs.

I'm not sure wind shake has anything to do with wind. As I recall from discussions with forestry people at Virginia Tech they are unsure and think it may have to do with viruses or other infections more than wind. That's an old memory and a fairly dim one, so don't take notes.

wind loads...shake

Tom Dunlap

Wind shake or ring shake has nothing to do with wind. That's an old folktale. It's from a virus

Wind loads on trees have been studied by Dr Ed Gilman at the U of Florida. Google something like 'Gilman wind machine' and watch his videos and read his research.

When a static load becomes dynamic the physics change. Trees grow as a static structure just like a skyscraper. They flex and sway in winds or rain/ice/snow loads. The leaves furl and roll up to become more streamlined. That's an amazing video tonseee too. Once the static load threshold is met they fail and the pieces react in a dynamic way. I'm using static and dynamic in the engineering context. Much different than in 'just' physics

After a hurricane passed through the pine plantation area of Georgia vast swaths of trees were broken. No surprise. What wasnsurpring was that the failed tops were found pointing opposite to the hurricane track. Dr Kim Coder from University of Georgia studied the failures. Most of the trees failed and left 20-30 foot stumps and tops laid 'backwards'. Huh?! Here's what happened. Front edge of

The hurricane pushes the trees forward. The tree trunks, tops and root plate flex...statics. Then the eye passes over those leaning, flexed, trees and before they can dissipate the energy they've absorbed bending forward they snap back and the tops brea...dynamic loads. Kim did his research and calculated the force that was neede to flex

The trees. Pretty amazing numbers. He also came up with a formula that calculates wind load. It's a rough number and better calculations are used now but at

Least anrule of thumb

Trees are so amazing!

Strange indeed...

John in NM

I would have imagined that the time scales involved were too long for such an effect, though I'll admit I don't know how long the change in direction takes due to an eye passing. On the order of hours I would guess.

I could easily imagine the top snapping backwards and breaking due to a sudden removal of a large and relatively consistent wind load - such as when the front of the eye passes over a tree. Isn't the wind speed gradient very steep at the edges of an eye?

I'd Wonder

Mark Mandell - Gone Round In New Jersey

if the big pressure drop in the eye would have some effect as well as the wind speed change. Eyes can drop up to 15% off the atmospheric pressure outside the storm. It can be an ear-popping experience.

We loose tree here when the high winds blow out of the east and northeast. Arborist explained that our forests grow in the prevailing westerlies so that the strong roots tend to group on the west side of the tree. The east side is thus weaker and subject to being up-rooted in a nor-easter. Perhaps the cyclonic winds of a 'cane find the weakness of the trees' growth structure?

Re: more confused *LINK*

William Duffield

All trees are not oaks. Probably the only reason there are any giant sequoias left standing is due to their fracturing, or more descriptively, shattering, on being felled.


Sequoiadendron giganteum Uses

Re: wind loads...shake

Tony - Memphis

So are hurricanes! Been there, done that.

Interesting info, thanks for posting.