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  1. #1
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    Default Interesting jarrah

    Milled up some nice jarrah of what I thought were pretty ordinary logs during the week. The last picture the colour changes from light to dark about half way through the log. Anyone know why.
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  3. #2
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    Vertical changes in colour are often due to fungal effects.

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    Don't really care what causes it. I just like it!!

    Lucky you!!

  5. #4
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    Default Jarrah

    Never seen that before. , but it looks superb

    Maybe you just wet the timber, made up a story, to start a thread on Jarrah to make Easterners jealous??

    Seriously, I reckon Bob has has nailed it, fungal attack, or maybe water ingress
    Willy

  6. #5
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    Yep dat is a nice bitawood.
    Tim. A man of measurable mess.
    http://www.bushhavencottages.com.au

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    I'm wondering if it could be heat/fire? A turner in the US is experimenting with baking wood samples to achieve colour changes. So far he has produced quite dramatic changes from slight caramelisation to very dark changes. Interesting area to explore.

    No matter the process the timber shown above is both attractive & desirable.

  8. #7
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    Thanks for the ideas and comments. Seem to make sense. The pictures are a bit average but you can still make out the colour change easy.

  9. #8
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    I haven't seen that on Jarrah before.
    Could it possibly be that the tree was burned on one side ?

    I know that She-oak & Woody Pear have dramatic colour changes after a bush fire has passed over them.
    I have seen She-oak that is darker one side of the log compared to the other which was due to being burnt on one side.

    HTH
    Col
    Chucks are like potato chips....you can't have just one.

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    http://www.mandurahwoodturners.com/

  10. #9
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    The first two pics looks like birdseye jarrah , did this only occur on the first couple of cuts on the log ?

  11. #10
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    Nice find Rhett, one of two things could be happening with it depending on where the tree was growing.
    If the tree was from the bush. BobL is right and it would be a fungal attack. The darker part should have black specks through it.
    If the tree was growing on a farm it can be common to see this in a paddock tree more than a bush tree. All trees probably start their life in the bush, the bush is cleared and it becomes a farm. The farmer then feeds his pasture with fertiliser and the trees he may have left behind get to thrive on it as well. Large levels of nitrogen in fertilisers will turn jarrah pale for the reason being that the healthier the tree the more water it will absorb or consume.
    So if it makes sense, the tree in question may have started as a bush tree and been harvested. The one you have is the regrowth tree that lived off a large root ball, hence the dark colour at the base.
    I probably haven't explained too well but hope you get my drift.

    Nifty

  12. #11
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    Default Colour change

    The colour change topic has been on my mind lately. Thanks for the comments. Just to clarify the first two pictures are from a different log as the last picture with the colour change. I had some jarrah lining boards machined up yesterday and the colour changed appeared again. Very obvious along a gum line. Check out the pics.
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  13. #12
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    Quote Originally Posted by Bennetts Timber View Post
    The colour change topic has been on my mind lately. .... the colour changed appeared again. Very obvious along a gum line......
    Bennetts T

    Thought I toss in my 2 bob's worth with a plausible explanation for the colour change in your timber.

    I'll offer the suggestion that the colour change probably relates to the effects of the tree/timber responding tot he incursion of a wood decay fungus. The gum line as you describe is likely the CODIT defense line. An area of chemical reaction where the defense mechanisms of the trunk-wood try to wall off the incursion of the wood decay fungus. CODIT is the acronym for compartmentalisation of decay in trees. An established theory that was thoroughly researched and documented by the late Dr Alex Shigo, a leading expert in Arboricultural science, especially wood decay.

    The darker colouration thence would be areas where the fungus has possibly had some limited success at the incursion. Perhaps microscopic hyphae threads penetrating thru individual cells of the trunk-wood, there they excrete chemicals to try to digest their target material (could be the fibrous cellulose of the cell walls, or the target could be the lignin chemicals that fill the cell as it hardens on the layers inside the sapwood) Simplifying this a heap for the viewers.

    It is also quite likely that the fungal invasion has been contained by the tree's defenses and the discoloration is cosmetic and a not structural issue. If you look at lots of timber 'stains' in all sorts of species you may well notice this very effect.

    I work as an arborist and a few years ago I had the opportunity to sit thru a lengthy workshop by Prof Frank Schwarz, a leading authority on wood decay and he presented us dozens of slides of wood decay fungus affecting cells in timber in a variety of methods. I'm not any sort of authority on this but anyone interested in the topic will find enough jargon above to search further.

    Nice timber there that you have to work with. I'm still learning my way about my 2nd hand Lucas mill so I enjoy the time spent reading the posts here and learning from the more experienced contributors.

    Cheers
    RM

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