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Re: When is the best time to harvest timber? #3648 01/19/07 06:57 PM
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Tom Cundiff Offline
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Rudy said,
Quote:
Maybe we should do two or three with timber harvested at different times of the year and see what difference it makes when we light 'em up?
If we are going to stay on topic, I think we are obliged to. Tom laugh


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Re: When is the best time to harvest timber? #3649 01/19/07 07:03 PM
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Gabel Offline
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I'm in on the cannon carriage(s).

I found this in a list of navy records held at the National Archive. Perhaps these could the referred to experiments? If not, they would still be interesting to see.

"412. Reports of Experiments by Timber Inspector James Jarvis on the Preservation of Timber.
Jan. 15, 1850-Jan 24, 1855. 1 vol. 2 in."

"Arranged chronologically."

"These are narrative descriptions and tabular statements of the experiments conducted and their results. The experiments were conducted by Jarvis at the Gosport Navy Yard to determine the proper time at which timber should be cut, causes of dry rot, and measures to be taken to prevent the decay of naval vessels constructed of live-oak, white oak, yellow pine, and other types of timber.
Other Records"

Re: When is the best time to harvest timber? #3650 01/19/07 08:45 PM
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Tom Cundiff Offline
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I found that page:
www.history.navy.mil/library


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Re: When is the best time to harvest timber? #3651 01/20/07 06:00 AM
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Don P Offline
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I'm new here and hope not to step on toes in my first post. I've read and tried to pay attention to the topic over the years, Joel's question about older copies of the wood handbook had me checking my '55 copy. Nothing there about a season for seasoning.

A couple of things I noticed in the thread though that I can help with. Wood dries fastest in warm weather, 90 degree air even at high humidity has more capacity than dry cold air. The molecules are more excited about moving to new and exciting places when they are warmer too. There is an average air drying rate chart at the Forest Products Labs website somewhere.
I would bet they would answer a Q from the guild with a good response.

A start in the winter can often get the surface dry enough during cold weather to avoid bluestain and bugs come warmer weather. The slower surface drying may help with checking.

Sap does not go down, it may stop flowing but it does not overwinter underground. A broken water column is an embolism to the tree it cannot be re-established, that tissue is dead.

Conifers grow year round, thats why they keep their needles. They do grow painfully slow when the conditions allow in winter. The moisture content of some hardwoods is higher in winter, no transpiration from leaves.

One possibility I see is the change in starch and sugar content through the seasons, although that would seem to just trade one bug for another.

The general wood industry line is that it makes no difference, and I tend to agree. If time of harvest does have an effect I think it would be minor compared to proper piling and protecting the wood.

It would be neat to read the old report though.

Re: When is the best time to harvest timber? #3652 01/20/07 12:17 PM
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Newbiemy Offline
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http://www.british-trees.com/Oldsite/p10.htm
This is the link for John Evelyn's "Sylva", researched and written at the behest of the British Admiralty. At that time, it took close to 100 acres of 100 year old English Oak to make one ship-of-the-line.
If you spend the time to read it all, you'll note he refers to the ancients as though he talked to them last week!
As an arborist, I find some of the discussions fascinating, as we still argue points he presents!

Re: When is the best time to harvest timber? #3653 01/22/07 02:45 AM
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northern hewer Offline
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Hi all:

Again great thread and many good comments and points of view.

Over my many years trying to reproduce lumber for restorations and reproductions in these cases mostly white pine, trying to select logs of proper and equal quality was very hard to that that was available in the forests of the last century (1800's).

the trees were older with more heartwood then, and the tree stands now are of 3rd and 4th growth species, I suspect the genetics of the present trees are remarkably different now, the growth characteristics are also quite different now.

I do know for instance that logs floated in the pond for 1 or 2 years will cut exceedingly better quality lumber and will be harder and plane up nicer after air drying. We always floated good quality logs for a period before cutting, it also kept the beetles at bay.

In my day it was always considered better to harvest timber in the coldest part of the winter, and then saw and pile in the spring for one year for every inch of thickness to air dry. then re-pile inside for further drying and aging for another season. each year that you can keep the timber curing is better before use. It is hard to beat 5 or 6 year cured lumber out of an open shed or storage area.

NH

Re: When is the best time to harvest timber? #3654 01/22/07 09:00 PM
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Ken Hume Offline
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Hi Guys,

Sorry to dispell some myths but I think that we need to start dealing in hard facts.

One of the outcomes of the various dendrochronolgy projects being run in various parts of the UK would appear to indicate that there is no definite trend in when timber is felled. Dendro is sufficiently sensitive to determine whether historically timber was felled in Spring, Summer, Winter with no mention of autumn / fall (harvest time). These dendro results are reported regularly in Vernacular Architecture and inspection of these reports would not identify any particular season as being dominant.

Care needs to be excercised in interpretting these dendro related results since quick grown timber does not tend to date very well and many early (medieval)buildings appear to be constructed from fast grown timber thus results obtained are only from slow grown timber sources.

One of the earlier posts on this thread explains that softwoods continue to grow in winter and I very much doubt this to be true. For the last 9 years I have been systematically measuring and recording the (girth) growth increment of Douglas fir in my own woodlot and I have found that by late September growth has all but ceased. Girth measurements taken during winter consistently demonstrate a slight shrinkage of girth which I have generally put down to tightening of the bark as the requirement for growth subsides.

I think that each woodlot will have its own "best season" for being able to access and haul out timber and this would need to be taken in conjunction with seasonal labour availability thus the various practices reported earlier in this thread may relate more to popular myth than be supported by hard evidence.

Ken Hume


Looking back to see the way ahead !
Re: When is the best time to harvest timber? #3655 01/23/07 01:31 AM
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Don P Offline
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Continues to grow might have been a stretch. Ekes out an existance, contiuing to photosynthesize whenever conditions allow, might have been better.

The introduction to this paper is a good read, it does a better job than I did.
http://www.mta.ca/~dcampbel/SelectedPublicationsCampbell&Group/PrePrints/Sveshnikov%20-%20page%20proofs.pdf

This paper goes on to show that conifers often survive embolism from freezing of their sap. Whoops! :rolleyes:
http://www.plantphysiol.org/cgi/content/full/131/2/780

The intro of this paper descrides some of the sugar/starch relationships I was wondering about.
http://www.springerlink.com/content/q155257331535071/

I'm still reading through Sylva and enjoying it, the description of turpentining is great. I had tried searches for that info without success before.

My FIL had mentioned the boatbuilders in Holland float logs for some time before using them. They were not simply ponding them, they considered this part of the process. I'd be interested in more info on that, sounds like you know more NH?

Re: When is the best time to harvest timber? #3656 01/23/07 02:25 AM
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northern hewer Offline
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Hello again eveyone:

It seems that we are all learning a bit from each post, Ken yours was very scientific and interesting, I sort of agree that growth slows to a real c-r-a-w-l when the weather is -30 in this part of the hemisphere. The trees get so cold that frost can split them, a rarity but it does happen.

My opinion is that if there is a best time for cropping logs for harvest it would be when as much of the moisture, sap or whatever is not present, and in my books that would be in the slowest growing season, to me it just makes common sense, and less moisture to get rid of in the drying process.

I do realize though that commercial lumber harvesting goes on throughout the whole year, and plays no favourite when it comes to seasons.

All the major mills would and did float their logs to the mills if that means of transportation was available, it was the cheapest, and it kept the logs from drying out too fast before sawing happened.

The waterpowered sawmills usually required and had a good 3 or 4 acre mill pond to accomodate logs, with the only problem being bark and debris floating into the raceways and jamming the turbines.

Hardwood logs though would sink and needed to be handled in adifferent manner than softwood like pine which would not sink.

We would just roll in the hardwood logs along the shorelines, and when the water level was down in the mill pond, and we needed say an oak log for a particular purpose we would attach a mooring line that we could use to retrieve it when needed.

It seems to me that water seems to be different than natural moisture, and does not seem to be as much of a problem to remove as the natural juices, and if anything imparts an improvement to the quality of the lumber. I have had some of the old sawyers say to me over the years that "if you want good quality lumber float your logs for a while before sawing"

Small country sawmills situated away from water sources and powered by diesel, or steam engines (originally) didn't have access to water sources on any great scale, and the logs simply were cut and brought to the mill, sawn and then trucked home and piled until curing or use was needed, which ever come first.

NH

Re: When is the best time to harvest timber? #3657 01/23/07 03:17 AM
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Newbiemy Offline
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I know bowl-turners boil oak before working, to make it less likely to check. Also the largest kiln in this area steams oak to dry it! (Now that would be a physics lesson itself).

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