What's the best way to cut flooring from red oak growing on extreme slopes?

[crmorse]

I'm about to embark on cutting a lot of flooring from salvaged oak that's been growing on pretty steep slopes.  These are trees that have recently blown down or died from lightning strikes. I'm being picky enough to only take the straight large logs with no bows. (On my land, that means 20"-26" DBH and maybe a handful of 13-15" if they just happen to be easily accessible and in good condition.)

However, I've learned from this forum that even straight trees that were growing on a slope are likely to have a lot of internal stresses.  Since I know my purpose for the wood up front, are there approaches I can take during cutting to get the best yields?

1) My thought was that by quarter sawing and going ahead to rip into narrow widths now would help reduce cupping and twisting but I don't know if that's true.  

2) I'm guessing these trees will tend to have an off-center pith, if so, does it help to cut from one orientation or the other?

3) As far as stacking, my plan is to stack and sticker fastidiously as well as I have a strapping machine so I plan to tightly strap each bundle together every 2-3'.  This should help me keep the bundles smaller and easier to rotate around my drying area so that they get even wind exposure.

4) Does it matter if I mix subspecies of red oak together during cutting or drying? (obviously during installation I'll select by appearance)

I should probably start another thread about species identification, but I seem to have a mix of different oaks. I know my area is an oak-heath forest and these trees are up on the ridges but I haven't been able to really concretely nail down the species.  The habitat, bark, and leaves all match up with Chestnut Oak (aka Swamp Chestnut Oak) but the heartwood is definitively red oak and that's supposed to be in the white oak family.  The true white oaks have a very obvious bark that's easy for me to pick out.  Unfortunately, since these trees are already down and dropped the leaves, there's not much else for me to go on... Anyway, another thread it is for that.

Thanks in advance for any/all schooling for this long-time woodworker, first-time sawmiller.

[Jcald327]

Subbed for the advice of the experts.  My brain is going in about 5 different directions of cause and effect on how this will play out, and the best way to minimize warp/twist/cupping.  

Just a couple thoughts (again not a subject matter expert).

Cut it how you cut everything else, if you find your releasing tension and board/slab twisting in all sorts of directions, roll the log and take a stab from the other side.

While quartwrsawing is the most dimensionally stable is it the most stress free cut?  I feel like each layer (growth ring) is relatively consistent stress wise, whereas as the tree grows, rings farther inside will be placed under more and more stress as the tree grows.  Does this negate the benefits of QS if the all twist before they dry?

Keep it on the narrow side of board width, try to make sure you stagger some of your growth rings when making T and G or picking your face sides.  Just like edge gluing table tops so the forces balance each other out (obviously this is applied to flat sawn versus qs).

Enough unsubstantiated guessing, disregard all, and take advice posted below this line.

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[jeepcj779]

   Having zero experience as a logger, and also zero experience as a sawyer, I will take a stab at providing a non-educated guess. Trees growing on a slope should not have that much more stress than a tree on flat ground of the same species. There may be different stresses on the root system on a slope, but the bole of the tree grows straight up from the ground, sloped or flat, and is perpendicular to the force of gravity (for most tree species). As long as the branches are evenly dispersed, the tree should not experience any extra stress from the slope as long as it is growing straight up at 90 degrees.
  It is possible on extreme slopes that there will be more shading on one side of a tree, and because of that less branches and uneven growth rings on one side or the other. On really long slopes, the effect of down drafts running the slope on on regular basis might have an effect on tree stress similar to other trees subject to repeated wind pressure from one direction all the time. I have also seen trees on slopes with a little curve right where they come up out of the ground, but not more than a foot or two, so should not make much of a difference to the rest of the tree.
  I would cut the trees the same way you would for a normal tree, and deal with any stresses as they appear. Quarter sawing should be the best way to mill for flooring.

[Magicman]

1) My thought was that by quarter sawing and going ahead to rip into narrow widths now would help reduce cupping and twisting but I don't know if that's true. 2) I'm guessing these trees will tend to have an off-center pith, if so, does it help to cut from one orientation or the other?

There is no "one size tree/log fits all", which means that with all sawing you should treat each log as an individual.  I would want to buck the butt log as far from the stump flair as possible to avoid the compression stress.  (At least 2'-3' from the ground.)

1) Yes, the flooring should be quarter/rift sawn rather than flat sawn.
2) For flooring I prefer that a board tends to bow rather than crook (both are bad) so with off centered pith logs, the saw through would be from either the hump or horn face.  This would be the face that the pith is either the closest to or furtherest from the log's edge.

[Don P]

A little bit about how trees try to right themselves. Softwoods try to prop themselves up from the underside of the lean by producing compression wood, it is high in lignin, the glue part of wood, stiffer. The cells tend to be made internally somewhat crossgrained so there can be significant lengthwise shrinkage during drying or seasonal change. The grain has a dull, peanut butter, appearance. It is trying to buttress itself up. The wood is stiffer but unpredictably weaker.

Hardwoods throw a strap of stretchy wood over the top of the lean and try to pull themselves back upright. This tension wood contains a unique layer of rubbery material inside the cell walls. That can make it hard to sand and work, having a fuzzy appearance. If you take flatsawn off this hump it will tend to bow, if quartersawn it will accentuate the crook that QS often has anyway. That tension wood is going to carry well up the tree, it is fighting gravity its whole life as it gains weight on that uncentered base. There is often useable wood but the take of artisan firewood is going to be higher. The wood is springier than normal.

[crmorse]

Are there ways to identify (likelihood) where/if a particular log has this before cutting it up?  I'm not afraid of hard work giving it a fair try. But the info Don P posted seems kinda grim.  If there was a way to look at a particular log and have (for example) 75% confidence it's not going to work out, I'd rather save myself the consider trouble of hauling it out of the woods.

Let's say I have a red oak on the ground with 17" of heartwood and I section it and find that the pith is mostly centered and the growth rings appear symmetrical. Is that any indicator it's worth trying anyway?  

Another example, I have a 24" chestnut oak that just blew down. The bole is over 40' to the first branches and there's still a good 10' above that before the first fork. But it was growing on a slope near 30º.  What say the braintrust about trying out that tree? (at least it's near my trails so relatively easier to recover)

Note: I'm not arguing here, just trying to get a sense of how reliable/variable these results are and the magnitude of the problem.  I'm in a great spot right now where I haven't over-committed to anything so I can easily redirect if the facts aren't friendly.

[Magicman]

Off center pith is bad, centered is good, so the question is how much off center?  As I mentioned above, each log is an individual and there is no magic formula to tell you which will or will not exhibit bad characteristics but the more off centered it is you can expect more problems.  Saw through from the hump/horn face generally produces lumber that will bow.  Sawing from the sides generally will produce lumber that will crook.  Since the logs are not perfect, either can yield some lumber that will twist depending upon the log and the sawing pattern.

EDIT:  I hesitated to even address this topic because the question is legitimate but the answer is elusive.   :P

[Don P]

MM is spot on. Our woods are mostly 40% slopes or better and there are perfectly fine trees, and some that are better for firewood, some I just use the sawmill as a splitter while figuring that out :D. Pistol butts in an area are usually a sign of slope movement, the tree is trying to right itself on a sliding slope.

[Southside]

Side hill trees present their own challenges for sure, to turn those into flooring only adds to the complications. There are enough issues with flooring when it comes to grain changes within individual boards, seasonal movement, etc that adding significant growth stress is not something that will help you.  The problem is that things may look good coming off of the mill, and during air drying, but once you put them in a kiln to get the lumber down to 7% MC, that's when you are going to see movement.  Add to that the fact the pith is much more difficult to contain to one or two boards and the odds of a successful endeavor fall quickly.  Can you do it - yea, maybe, sort of.  Should you do it?  Not me, I would find another use for those logs.  

[jeepcj779]

Can someone explain why trees on a stable slope might have more issues those on flat ground?

[Ianab]

Can someone explain why trees on a stable slope might have more issues those on flat ground?

It's possible that the tree has been shaded by other trees higher up the slope, and has grown on an angle to reach the light better. Or it has more branches on the downslope side and an off centre pith. 
Some trees / situations aren't affected, but others can have a slight banana bend and an off centre pith which are signs of trouble ahead. I can show you some local trees that grow out of a stream bank horizontal for 6 ft, then curve to vertical once they reach the sunlight. 

[jeepcj779]

Ok. I have seen trees do what you describe by bodies of water. I acknowledge the possible up-slope shading that might occur, giving the tree more sun exposure and branching on one side of the tree. I suppose that is similar to the imbalance on trees at the edge of a field on flat ground. I guess you learn to read the trees for what stresses might be inside.

[Ianab]

Yup, it's not going to affect every tree, or 90% of the trees in NZ would be useless.  :D

It's just something to be aware of and watch for. Like the edge trees around a pasture, same sort of effect. 

[JRWoodchuck]

What is a pistol butt?

[GullyBog]

The very bottom of the trunk bends like an older style pistol handle.  Common on a steep slope.  Interesting what Don P said about pistol butt being an indication that the slope has moved.

[JRWoodchuck]

Makes sense hadn't heard the term before. Thanks. 

[tmbrcruiser]

FYI Chestnut oak is in the white oak family.

[crmorse]

FYI Chestnut oak is in the white oak family.

True enough, and a problem I'm about to start another thread about. I have both. But I'm having trouble identifying the difference between chestnut, swamp, and swamp chestnut (aka chestnut swamp). They all grow in the same habitat (or so I've read) and I definitely have at least 2 of them.  The trouble is, right now none of them have leaves on so the only thing I have to go by is the bark and location. From what I've read, swamp likes the bottoms (which I have) and chestnut likes the ridges (I also have). 


The problem is I have certain trees that the location, bark, and leaves (on the ground nearby) all say Chestnut but the heartwood is definitely red.

For my purposes, the problem is academic because I'm not taking down any live trees and I'll decide how to cut it on a per-log basis so by then the color will be clear.

Can someone explain why trees on a stable slope might have more issues those on flat ground?

It's possible that the tree has been shaded by other trees higher up the slope, and has grown on an angle to reach the light better. Or it has more branches on the downslope side and an off centre pith. 
Some trees / situations aren't affected, but others can have a slight banana bend and an off centre pith which are signs of trouble ahead. I can show you some local trees that grow out of a stream bank horizontal for 6 ft, then curve to vertical once they reach the sunlight. 

I don't know if I'm underestimating the problems ahead, overestimating my ability to "read" a tree and be choosy, or both.  But I'm not seeing those issues on any of the logs I've selected.  My banks are rocky but shallow, since reading this I've looked around some more and I don't see any signs of pistol but or even many bananas. They all just grow tall until they blow over due to a shallow root ball and all the nearby supporting trees were logged out a while ago.


Here's an example of the good ones I'm seeing (granted, this one was from a bottom and snapped off 5' above ground, but this is still representative of what I'm choosing).  It's 18" DBH and 50' to the first crotch where it's down to 14". I *think* this one really is a Chestnut but @tmbrcruiser, I welcome your input.


Second is tree2.jpg, hopefully proof that I'm not being argumentative and actually learning. Tree2 is one I fell in love with when I first found it because it's near the road and fell down perpendicular to the slope making for easy recovery and despite the moss growing, is still in solid shape under the bark. As you can see in the picture here, this one does have a moderate pistol butt[CHECK]. But oddly, it appears to be up-slope not down. It's only for the first 3-5 feet which I'd planned to cut off anyway.  However, looking at it with fresh eyes this morning I see it also appears to banana[CHECK]. I don't remember that when I was walking so it might just be photo angle but I'll assume not.  It has large branches only on the downhill side[CHECK] and as you can see, was growing on a pretty good slope[CHECK].  It's 25" DBH x 50' x 16" (est. 880bf Int1/4).  Given all of the above, would ya'll say this is only firewood or worth trying?



Ok, last question. I assumed that floor boards would be *easier* to achieve because the boards are narrower, thinner, and shorter giving the best opportunities to avoid twist and warp.  However, from what I'm hearing here, it sounds like just the opposite.  Is that true or am I missing something (I usually do)?

[Don P]

Flooring is often made from lower quality wood for the reasons you understand. I can't say that I've ever sawn a tree quite that mossy but I'm not averse to putting just about anything on the mill. The sapwood is going to be rotten , try breaking some of the heartwood and see how it does. You'll likely have some discoloration, which might be pleasing, or not, just see if it appeals. Waste will be high but if it is just your labor nothing wrong with that. When I get into dead trees the bugs have usually started, I soak it thoroughly in a borate solution. Species doesn't really matter, aesthetics is all.

We brought some wood up today, it was a large pasture cherry ~3' that had blown over, color is beautiful but being a large old pasture tree the cows had damaged the roots, bacterial infection caused a lot of shake. It was real easy to read that the moment we cut it off the rootball. We culled a lot as we sawed but it is such pretty wood we stacked anything that looked like it had a few good feet in it. As it dries we'll lose a bunch more. The better trash will make pallets, the worse will burn just fine. I wouldn't want to try to make a living on sawing stuff like that but it kept us off the street so no regrets.

So really its your call, the losses in sawing will be high, the losses in drying will probably be as well. I don't see anything in those or in your woods that particularly says high stress just from the looks of them but they will tell you as you open them up.

[tmbrcruiser]

The tree in the first picture appears to be chestnut oak to me. Swamp chestnut oak has bark very similar to white oak. The swamp chestnut oak here tends to have an irregular grain and wider sap ring than other white oaks.

When I'm sawing logs I think will have more side warp the normal I tend to saw 1/2" over and straight line after drying. Just a thought for you to consider.