[permaculture] what makes black locust last so long?

paul wheaton paul at richsoil.com
Tue Aug 26 00:41:51 EDT 2008

So I went to add this excellent link to my online notes and I see that
Toby Hemenway did, indeed answer this question some time ago.  And I
even responded.  How could I forget that?

His response was quite interesting.  Something about big heaps of
natural fungicides that are strongly locked up in the wood.  So the
wood won't rot and at the same time the fungicides don't ooze into
other stuff.

More at http://www.permies.com/permaculture-forums/224_0/organic-practices/what-makes-black-locust-last-so-long-is-it-safe-for-gardens

On Mon, Aug 25, 2008 at 6:46 PM, paul wheaton <paul at richsoil.com> wrote:
> Thanks for the link Jay!  Lots of excellent info!
> Some of it was over my head, but I did manage to learn quite a few things.
> I tried to find out what flavonoids were, and I found out that they
> prevent cancer.  But that doesn't help me to understand how they make
> the wood last so long.   Do flavonoids poison natures composters?  Are
> flavonoids like some sort of natural plastic?
>> http://www.lib.ncsu.edu/theses/available/etd-11242003-154755/unrestricted/etd.pdf
>> 2.4 Secondary Metabolites of Black Locust and Effect on Animals
>> As mentioned previously, the heartwood of BL is primarily used for fence
>> posts,
>> poles, railroad ties, and mine timbers and can endure for over 100 years in
>> the soil. Its
>> remarkable decay resistance is due to high flavonoid concentrations (6% of dry
>> weight),
>> specifically the constituents, robtin (15,000 ppm), robinetin (20,000 to
>> 80,000 ppm) and
>> dihydrorobinetin (53,000 to 176,000 ppm)(Smith et al., 1989). Other,
>> flavonoids present in
>> the heartwood are butein, butin, fisetin, fustin, and liquiritigenin (Duke,
>> 2000)
>> On Monday 25 August 2008 12:59:21 pm paul wheaton wrote:
>>> I have asked this question about 20 times in all sorts of different
>>> places.  Any time anybody seems like they might possibly know ...
>>> So I ask it again here.
>>> In case nobody knows, I hope that somebody might carry this question
>>> with them and maybe some day spot an answer.
>>> So we know that black locust wood lasts a long time.  Old time farmers
>>> would call it "stone wood" claiming that it would last longer than
>>> stones when used as fence posts.
>>> Why?  Does it have some anti-fungal property?  Anti-microbial?  I've
>>> heard some people say something about it could be because it is just
>>> so dense - but that doesn't seem right either.  Other dense woods seem
>>> to decompose fairly rapidly.
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