Compression Wood, Tension Wood, and Eccentric Growth

Discussion of general forest ecology concepts and of forest management practices.

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Jenny
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Compression Wood, Tension Wood, and Eccentric Growth

Post by Jenny » Wed Nov 10, 2010 11:23 am

ENTS,

I am taking a course at NY Botanical Garden on Winter Tree ID. And I am astonished at how much I don't know.

One of the numerous readings assigned is a very informative (for me) and rather challenging (for me) article written by G.P. Berlyn for Encyclopedia Britannica's "tree" entry.

Among the difficult concepts for me were the definitions and roles of compression wood, tension, wood and eccentric growth. And as these terms were introduced on the last 25th page of a 25 page article, my mind just could not grip any of it - except that these functions seem to be essential for upright and sturdy growth. I think this may be over my head as I even struggle with the differences between the cambium and the cortex. But I try....

The recommended field guide is the The Sibley Guide to Trees - the one I don't own, of course. I think I remember some of you giving it a pretty good review?

Here is 'my' white ash tree which has already dropped its leaves. I planted this 2 years ago - the first tree I ever planted. It is alive and well in The Forest of NYBG at a junction on the Forest Trail. This pic of 'her' is great for elements of winter tree id. A fresh leaf scar and conspicuous bud. Of course, this is one of the easier winter id trees....

Jenny
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Suburbia is where the developer bulldozes out the trees, then names the streets after them. ~Bill Vaughn

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Jenny
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by Jenny » Wed Nov 10, 2010 5:46 pm

Well, coming up with superficial results that don;t seem to amount to much more than I already figured - that tension wood and compression wood help stabilize a tree....something about a gelatinous layer I had no idea about and have no idea where that develops in the cambium or cortex or wherever.

Reading a semi-coherent article: "Lignification and Tension Wood" by Gilles Pilate in Comptes Rendus Biologiques.

I am attracted to this concept because it is a way I did not know trees could help themselves. Always good news. Always thought they were at the mercy of arborists (not a judgmental statement!) But I also see how important this is in the timber industry. Tension wood and compression wood can cause structural problems and cutting problems with the wood used for commodities? Do I sort of know what I am talking about?

Go trees! Keep yourselves from toppling!

Jenny
Suburbia is where the developer bulldozes out the trees, then names the streets after them. ~Bill Vaughn

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Steve Galehouse
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by Steve Galehouse » Wed Nov 10, 2010 6:57 pm

Jenny-

Compression wood is developed in conifers and "pushes" limbs up from below, tension wood is in angiosperms and "pulls" branches up from above. I'd recommend that you skip Sibley's guide, I feel the Peterson's guide is better overall.

Steve
every plant is native somewhere

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Jenny
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by Jenny » Wed Nov 10, 2010 9:18 pm

Great, thank Steve. I already have Petersons!

Jenny
Suburbia is where the developer bulldozes out the trees, then names the streets after them. ~Bill Vaughn

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dbhguru
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by dbhguru » Thu Nov 11, 2010 4:03 pm

Jenny,

I second Steve's choice. Months back I did a review of Sibley's book for the Torrey Botanical Society. Although the book has some good features, it leaves much to be desired.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
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DougBidlack
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by DougBidlack » Thu Nov 11, 2010 10:02 pm

Jenny,

I guess I'll be the third person to dump on the Sibley Guide. Don't buy it! I picked it up in a bookstore in Cali last fall and I put it down after a little look. The problem for me is simple. You can't keep trying to put more and more species in a book that remains the same size and then get good treatment for all species. It's hard enough with just the eastern species let alone trying to cram all the eastern and western species into one little field guide. I'm sure this decision was based entirely on economics. Poorer info for more people = bad book. If you want to spend more of your money on a good field guide, try going the other way. There must be some kind of field guide to New York trees, no?

Doug

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dbhguru
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by dbhguru » Fri Nov 12, 2010 8:40 am

Doug, Steve, Jenny, et. al.

One expects more from a renown bird expert and consummate artist like Sibley. We expected the same attention to detail in drawings, but outside of a few leaf drawings, that detail is missing. The thumbnail drawings of bark are all but useless. In addition, he quotes the same outdated and incorrect sources for tree dimensions as the majority of other guides. That constitutes lousy research. Doug, basically, you put the nail in the coffin - far too much information in far too small of a space. What's the point, other than to trade on your reputation and sell some books?

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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Don
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by Don » Thu Nov 18, 2010 6:04 pm

Jenny-
From a consumers view, it does matter that the timber grader/miller paid attention to tension wood/compression wood, otherwise you the consumer would end up with what is known as dimensionally unstable lumber. Timber mills go to considerable effort to store logs, saw them, sort them, kiln-dry them, and sticker them for transport to the Home Depot of your choice...boards that have tension wood/compression wood/juvenile wood/other eccentric growth patterns will respond to stress (loading) by bending or breaking where the grain diverges from parallel. You can still get these lower grades of lumber, where warpage isn't an issue (hmmm, pigeon sheds, etc...;>), usually at bargain prices.
-Don
Jenny wrote:Well, coming up with superficial results that don;t seem to amount to much more than I already figured - that tension wood and compression wood help stabilize a tree....something about a gelatinous layer I had no idea about and have no idea where that develops in the cambium or cortex or wherever.

Reading a semi-coherent article: "Lignification and Tension Wood" by Gilles Pilate in Comptes Rendus Biologiques.

I am attracted to this concept because it is a way I did not know trees could help themselves. Always good news. Always thought they were at the mercy of arborists (not a judgmental statement!) But I also see how important this is in the timber industry. Tension wood and compression wood can cause structural problems and cutting problems with the wood used for commodities? Do I sort of know what I am talking about?

Go trees! Keep yourselves from toppling!

Jenny
Don Bertolette - President/Moderator, WNTS BBS
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deepwater
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by deepwater » Sun Dec 12, 2010 1:15 pm

When I moved up here to Maine I needed to log off several huge pines (18) 100' +,,I was in need of some lumber anyway so my killing of pare of my forest went to very good use,,I was directed to an old guy with a portable sawmill and he showed up and we went work turning long and round into long and flat,,I saw him turn and twist the logs all over using the hydraulic rams on the mill,,I knew he was reading the log to get the best and most cuts from each log ,,He was a master at cutting,,1500 bf and no warping or twisting,,He said that when squaring a log up he could feel the tension in a log and knew to cut it using that tension to keep the other boards strait,,I just cut 12 more down last summer (safety) and he will be here when he can to make more boards for me ,,I hate to cut them down but I love his work
Through my eyes you still see,,through my lungs you still breath,,in my heart you will live forever

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Jenny
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Re: Compression Wood, Tension Wood, and Eccentric Growth

Post by Jenny » Sun Dec 12, 2010 1:46 pm

Don and Deepwater,

Wow, I can't believe how important tension/compression etc. are to the,well, art really, of making the tree into boards. I would love to see it. Maybe I can dig up a video. How complex these trees are.

And, Deepwater, I'm from Maine! Where are you located? I grew up in Falmouth next to the Audubon at Gilsland Farm. Now, NYC, where I've learned everything I never knew about nature. But the big fields, marshes, mudflats, ponds, and woodlands were a paradise until I was about 13 when it all became completely boring. I miss Maine so much so always jump a the opportunity to talk about it....

Thanks!

Jenny
Suburbia is where the developer bulldozes out the trees, then names the streets after them. ~Bill Vaughn

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