About a year ago, I cut down a Post Oak tree, stripped its bark, and reassembled it inside a bar with the limbs re-attached, supported by threaded rods about midway out. I knew there would be some changes as it dried. I told them I was pretty sure it would split as it dried. If I did the project, I would try to help keep it looking good, but I gave no guarantee. Any future work would be extra.
Here is a link to their website showing the tree. I hope this doesn’t sound like an ad for them. I was over last night working on it, and have been surprised by how it has changed. http://www.capisrestaurant.com/
After cutting the limbs off and dropping the trunk, I ripped it down the middle, then cut a long V out of each half, leaving it hollow, so I could assemble it around a 6 x 6″ steel post which supports the roof.
The limbs were cut off with a long scarf joint, so I could bolt them back on when I got it inside. They also are supported near their middle with threaded rods up to the roof. I expected them to sag under their own weight as they dried, so I pushed the ceiling tiles up, and cut them at an angle level with the ceiling grid, then backed the drop in tiles with plywood, so I could screw down into the ends of the limbs to hold them up out there. They appear to vanish into the black ceiling with a nice effect.
I expected the limbs to split down their length at random, so I plunged my circular saw in and made a rip cut from the top hoping to give relief to the stress up there so the splits would be on top, away from the people eating below.
Before I tell you how I was surprised by the changes, I would like to hear what you would expect the tree do as it dried.
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These are educated guesses, but whole trees act quite differently, and less predictably, from sawn planks:
The hollowing of the main trunk would have reduced the risk of its splitting, it became a tube that could change in diameter without a lot of stress developing as the wood dried out.
In my experience wood doesn't sag as it dries out, the limbs were just as likely to stay in place as they were to rise or fall.
The slotting of the branches was a good plan, but knots, wyes, and spiraling grain might have left areas with local stresses that couldn't be relieved by the slotting and so there might be several areas that have small checks rather than large splits.
Nice piece of work, it must have been a challenge.
Shop Manager for FWW Magazine, 1998 to 2007
John, You have a good analytical mind. You are right on most of your predictions.I guess everybody knows not to expect lumber cut from limbs to turn out to be worth much, but we all hear about spacing stickers close, because planks can sag in between before they dry. The limbs have lifted up the tiles, and had to be cut off several times.There have been no splits in the trunk. As you and I both predicted. Hollowing the trunk allowed it to move without the usual checks which occur when the heart is solid. But none of the limbs have checked, and the saw kerfs were closed tighter than the day when I ran my circular saw down them. I have been back about four times to cut some of the limbs off which were lifting the ceiling tiles up on the ends. Rather than the limbs sagging from their own weight while green, I guess the greater shrinkage ratio of tension wood on the top half of the branches contracts more during drying than the compression wood on the bottom. Also, some of the long limbs became shorter, pulling the ceiling grid in toward the tree. Whether this was due to the contracting radius of the trunk that the limbs radiate out from, or an actual shorting of the limbs, due to the above, or some spiraling grain / tan ratio, I can't say. I am just happy that it made it through the one week warranty that I gave them before it self-destructs. %]
As the entire shrinks a bit I think that the limbs are pushing and pulling away from the ceiling. Maybe you are seeing some shifted ceiling panels? Some of the threaded rods supporting the middle of the limb may either have a lot of tension in them or are slightly buckled.
How did you move the trunk into the restaurant?
Nothing?
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