Preserving a slice through a fir

[Tim W]

A big old fir tree that used to stand in the middle of the village has been cut down. A slice has been cut from the lower trunk and has been given to the village school. The idea is that the school will count the rings (about

220 of them) labelling historical events and make a permanent display of local and world history with reference to the tree rings.

Nobody so far has volunteered to clean up the rough sawn slice and treat it in such a way that it will not fall apart. I am not even sure it is possible to do it with garden shed tools and equipment.

I would be grateful for sugestions or experiences.

Tim w

[Lew Hodgett]

RE: Subject

Does your state have an agricultural extension service?

If so, they can at least point you in the right direction.

Lew

[diggerop]

I'd contact the conservation dept of a large museum for advice.

diggerop

[Tim W]

I am not in the US but the UK so I don't know what that is.

Tim W

[J. Clarke]

In the US it is a government service providing informational assistance, soil testing, etc to farmers, gardeners, and the like. I'm sure the UK has something similar but have no idea what it would be called.

You might call Forest Products Laboratories in the US

--while they are a US government agency they will answer questions for non-US citizens on an available time basis. Odds are that they have a publication telling exactly how to do this in excruciating detail, but a quick look on their site doesn't find it.

[DT]

That's a nice project. Here is what I would do.

Make a good cut with a sharp chainsaw. Cleanup one side with hand planes. Then bag it and soak the entire piece in PEG, this replaces the water with the PEG and prevents cracking. It will take a bit of soaking, months at least depending on the thickness.

[Phil Kangas]

Several years ago I saved a disc of black cherry similar to what you have. What I tried was to wrap mechanics wire around the perimeter and pulled it as tight as I could. The wire was run around twice and the ends were twisted as the wire settled into place. The disc did not split on a radial as others had. Now that it is dry it'll stay that way. YMMV, good luck. How many of these discs do you have to work with? phil kangas

[dpb]

So what, this is roughly 4-ft in diameter, then, I'm guessing?

How thick did they make the slice(s)?

It's essentially impossible to prevent checking an at least some splitting in a section that size. Hopefully they saved several sections so you're not counting on only one shot at it.

Bruce Hoadley starts his book "Understanding Wood" w/ a tale as a kid of trying the exercise that's a good object lesson... :)

I personally don't have experience in trying to do so for large sections; I'd second the idea of seeing if can get some advice from a conservationist who might have place to send you if not direct experience. There are some slices of very old redwoods but iirc most do have pretty severe splitting although have held together enough for the purpose.

I'd think the PEG somebody else suggested a good way to start; you definitely want the drying process to be quite slow.

In UK don't know your sources for such info, you could do a search on the US Forest Products Laboratory site and see if could get any help--I think they have a way to ask questions--this is probably a fairly frequent one, maybe there's an FAQ.

--

[upscale]

If he decides to go this way, he can use this kit to accomplish it.

[Tim W]

Tim w

[Tim W]

...rough sawn slice and treat it

yes, roughly.

I don't know. So far I have avoided showing any interest. I don't want to get involved unless there is a reasonable chance of success.

I doubt it.

[David Nebenzahl]

On 11/6/2009 12:58 AM Tim W spake thus:

In addition to looking up PEG (probably a good suggestion for preservation), also do a search for information on dendrochronology, which is the study of tree-ring dating. There is probably at least one institution involved with that in the UK, so you might try to contact them.

Here in the US, there's a dendrochronology department at the University of Arizona in Tucson; you might look them up at

luck.