Reaction wood

[Billhook]

So I suppose I think that the defintion of reaction wood is that it is the wood of special characteristics that reflect the tree's reaction to abnormal circumstances that differ from a tree's progressive and norma self-optimisation.

 

 

A large Ash came down in the last big storm and it obviously had been rotten/diseased for some time at the base and formed reaction wood to support the tree on what was left. This area was less than half the original area of the trunk.

 

When I cut it with a sharp chainsaw, I thought that I must have caught the blade as it was hard as hell and the saw went off at an angle. I stopped sawing and tried the saw on another branch which it cut easily.

 

So I left this substantial block of wood on one side as it seemed so unusual.

Is this reaction wood sought after for carving. turning or other purposes?

[jomoco]

But there's nothing abnormal about wind, even occasional high winds IMO.

 

Ever notice how some hardwood and conifer branches of small diameter cannot be easily broken in a downward direction, but snap off quite readily when bent upwards?

 

Jomoco

[daltontrees]

Attached is what I was thinking of for the amended definition in wikipedia.

Wikipedia edit.pdf

[daltontrees]

So I suppose I think that the defintion of reaction wood is that it is the wood of special characteristics that reflect the tree's reaction to abnormal circumstances that differ from a tree's progressive and norma self-optimisation.

 

 

A large Ash came down in the last big storm and it obviously had been rotten/diseased for some time at the base and formed reaction wood to support the tree on what was left. This area was less than half the original area of the trunk.

 

When I cut it with a sharp chainsaw, I thought that I must have caught the blade as it was hard as hell and the saw went off at an angle. I stopped sawing and tried the saw on another branch which it cut easily.

 

So I left this substantial block of wood on one side as it seemed so unusual.

Is this reaction wood sought after for carving. turning or other purposes?

 

I don't know. It soulds like classic tension wood, very very rich in cellulose and hardly any lignin. It would I imagine be very dense. The rings can be very close together, and sometimes tension wood can be almost white. Maybe the turning guys will come along in this thread and comment? If you had bother cutting it, so might they.

[treeseer]

Attached is what I was thinking of for the amended definition in wikipedia.

 

That's an improvement for sure. It still follows assumptions about normalcy and uniformity and homogeneity that I have not seen evidence of, but then I have not looked all that closely. The term may have more relevance for forestry and timber than arboriculture.

 

In my practice I go by external signs to guide assessments, and don't bother guessing about inner anatomy. Good on you for trying to improve wikipedia, but to my limited and non-expert-wood-anatomist view, all wood is reaction wood; some more than other. Kinda boring I know. anyway a few comments:

 

Reaction wood is wood that forms in place of normal wood as a response to gravity &∧ other loading--wind, snow, any weight...,

 

where the cambial cells are orientated other than vertically. &&where the cambial cells are wider....

 

The effect of reaction wood is to help maintain the angle of the bent or leaning part by resisting

further downward bending or failure. && It also can correct the lean!

[daltontrees]

Nice as ever to have someone else contribute to this.

 

I will make a few changes to the Wikipedia definition for your last cvomment but just remember I am not trying to invent anything here, just trying to make sure that the Wiki definition reflects established sources.

[sloth]

Is there anyone out there with a copy of the Dictionary that was published alongside Shigo's New Tree Biology that could help out by looking up a few definitions for me? I have what I need form the other authoritative texts.

 

The key ones are -

Adaptive Growth

Reaction Wood

Compression Wood

Tension Wood

 

Any help appreciated, thanks. It would even help me to know if Shigo does not have definitions.

 

Apparently my copy is AWOL, I did find my Bridgeman book and a couple of other gems though so it wasn't completely wasted time. Sorry, down to you now bttgaz...

 

Sent from my GT-I9100 using Arbtalk mobile app

[Gary Prentice]

Apparently my copy is AWOL, I did find my Bridgeman book and a couple of other gems though so it wasn't completely wasted time. Sorry, down to you now bttgaz...

 

Sent from my GT-I9100 using Arbtalk mobile app

 

Got it in front of me- looks like a lot of typing though:001_rolleyes:

 

edit; Maybe not so much after all,

 

Adaptive growth - no entry

Compression wood - no entry

Tension wood - no entry

 

Reaction wood - I'll start typing in a new reply

Edited April 19, 2014 by Gary Prentice

[Gary Prentice]

Reaction wood

Wood altered as the result of lean in a tree; compression wood forms on the underside of leaning conifers; tension wood forms on the upperside of leaning hardwoods or angiosperms. reaction wood differs greatly from normal wood. Compression wood has only about 30% cellulose compared to 42% in normal softwood. Its lignin content can be as high as 40%

The cellulose in compression wood is less crystalline than normal wood. There are other differences between compression wood and normal wood that include hemicelluloses and lignins. Tension wood may have as high as 60% cellulose. There is not so great a change in lignin when based on individual fibres.

 

Tension wood contains many different types of hemicelluloses and lignins not found in normal wood. Another type of wood found in softwood trees is called juvenile wood. It is not associated with lean, but as the name states, it is the wood formed early in the life of the tree.

 

The many so called superior conifers planted in the South have a very high amount of juvenile wood. The wood does not have the best properties for pulp or for solid wood products. Juvenile wood contains less cellulose and more lignin than normal wood. This is not good for pulp. We often fall into a trap of thinking that implies bigger and faster means better. With trees, health and high quality wood does not mean bigger and faster.

 

Almost all the attention in selecting trees has gone to growth rates, or outside features. It id time to start selecting for inside characteristics. Wood indeed, is a reactive substance. Its variability is what makes it valuable, yet its variability can also make it a problem.

 

Alex Shigo, A new tree biology dictionary. p90 1986 ISBN 0-943563-05-4

[daltontrees]

Thanks for taking the trouble to type this all out. It's what I needed to know. In short Shigo supports if not originally puts forward the definition of reaction wood as being based on resistance to gravitational stress, specifically leaning stems and branches.

 

I'll tidy this all up in a day or two.