This is primarily for Bill Tindall, since he impresses me as very knowledgeable about logging and wood in general. A friend of mine recently gave me five tiger maple boards he purchased from a sawmill about 15 years ago and paid ten dollars for the lot. One board is 12" wide, 1 1/4 thick and 11 feet long, and is dead flat, straight and true The others are narrower, and all of them have the best tiger figure I've ever seen. I was curious if Bill knows what causes tiger stripe in Maple. Someone told me one theory is that the tree grew on the edge of a woodlot and the wind, making the tree sway back and forth, causes scar tissue in the wood. My friend wouldn't take any money for the boards, so I made him a Shaker style sewing stand with a turned center post and tripod legs. Just finished it and it looks great with the tiger stripe. Anyone with info on the cause of the tiger stripe, please join in.
I have never read why some trees develop curly grain. I have seen curly grain in poplar(one log), cherry (uncommon), ash (from a particular area), oak (rarely), walnut (one log), soft maple, (common), hard maple(less common).
Curl shows up in rift and quartered grain boards best.
I don't think that developing curly grain has anything to do with growing conditions and I am sure it is nothing to do with swaying trees. This topic might be something Wengert discussed if someone knows how to search his teachings.
The conclusion is that there is a genetic component but that alone does not cause curl. I found other references that suggested a balance, or imbalance, of cell growth hormones was responsible. Environmental and/ or genetics could result in an imbalance.
Bottom line: The cause is unknown and curl can not be reliably propagated from known curly trees.
I recall getting slab wood from a mill in Newcomb, NY in the 50's. Much of the birch from this old growth logging site was intensely curly. At the time I hated it because the slabs were hard to split! I mentioned this observation to a NYS forester old timer and he was aware of the concentration of curly birch from this site.
I agree with Bill in that the pattern shows best in QS or rift, but least or not at all on plain sliced / flat cut.
What is actually happening, if you peel away the bark, you can see that the grain zig zags actually sinuous curve from side to side. This doesn't show well from the flat sawn plane. However when rift or QS it appears to become in and out. What this does is show end-grain between the turns, so the end-grain absorbs light, while the cells in the turns are parallel to the face.
When you are using it from a rift pattern, that may have a situation like stacks of drawers. It is best to check from the ends to orient the slant of the annual rings all the same direction. Otherwise even if it is one of the same boards, if will reflect light differently. Usually you can just flip the board end for end to correct this. It is easy to make this mistake by laying everything out flat on the bench with diffused light above, then in the finishing stage when you start applying the finish it really jumps out.
As for cause, I can only guess. I've only seen one tree where the core when the tree was maybe 12" D had normal straight grain, then suddenly everything out from that was figured, so there is a head scratcher.
As for your friend's suggestion of swaying in the wind, I would be more inclined to think it would be a inherent mechanism to prevent splitting when there are rotational problems like a tree out from the corner of a structure may experience clockwise rotation from a N wind, then counter clockwise rotational forces from a W wind. If you have ever tried to split figured maple the evidence for resisting splitting is obvious.
For those of you that like to harvest your own lumber. One thing I have noticed is that once a tree becomes hollow, but may still carry some huge weighty limbs, they are more likely to have lots of figure in the wood outside of the hollow.
I disagree with the Q-saw/rift cut showing it the best. Not my experience. It shows pretty nicely in this flat sawn soft maple. I have turning blocks with nice curl on all 4 sides.
I have little experience with curly maple. We used to get some in our packs of maple and I pulled it out and sold it to a mandolin maker. Our lumber was flat sawn but of course the edges of boards were rift. I can't recall if curl went all across boards......I think it did.
However, in walnut and cherry I have seen many times curl that showed on the rift or quarter grain that was not so obvious/absent on the flat sawn surfaces. In electronics terms these curls are of greatly longer wavelength than the tight curl of maple. May be an entirely different origin.
