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3936Re: [fukuoka_farming] acorns

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  • sinniss@shaw.ca
    Dec 23, 2003
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      Hello all,

      I think the oak tree project is a wonderful idea. Some thoughts on this.

      From recent posts (thanks for these!), it looks as if selecting for
      "sweeter" acorns already has taken place, at least in parts of Europe,
      even though it is over a span of generations (as it would need to be)
      and the process isn't complete yet. This is good news, because the
      project needs that head-start.

      The difficulty, as I understand it, is that crossing two "sweet" oaks
      doesn't necessarily give you more sweet acorns from the next generation.
      Suppose there are a dozen different genes for tannin production. Unless
      the two trees in question are sweet because of the same gene, then when
      you cross them you are back to the standard level of tannin production
      (tree A was sweet because of it's unusual on gene 3, tree B was sweet
      because it is unusual on gene 8; when you cross them you get a tree that
      is typical at both genes). If I'm not explaining this well, perhaps one
      of the plant-breeding people on this list can say it a better. The point
      is that if you stay at it for a large number of oak generations you will
      get there, but it's not like breeding for non-bitter almonds (cyanide
      content in almonds is governed by fewer genes, or maybe just one). Ten
      plus years per generation of oaks, so this is a long term project. Worth
      it, though, in the end, and besides, even the less desireable acorns can
      be eaten if they are leached first.

      Tannins are indeed harmful in quantity, like anything else, and (though
      I've not seen it myself) it is possible make yourself sick with too many
      bitter acorns. Shuts down the digestive stystem, and hard on the kidneys
      too. That unpleasant taste is a warning worth heeding. Yes, some dilute
      tannin in your tea or your greens or whatever is fine, but those large
      quantities of tannins are there precisely to prevent the all the acorns
      from being eaten, whether by insects, pigs, or humans (otherwise, no
      next generation of oak trees). So, whether by treating the acorns or
      breeding the trees, you need to be eating a low tannin acorn meal to
      stay healthy if you want to make it a staple in your diet.

      Leaving the oak trees entirely to breed alone, without doing any
      selection, could lead back to bitter acorns. The tannins are there
      because they give the tree some advantage (or possibly they are there as
      a side effect of something else that gives the tree a survival
      advantage). Does this mean that the sweeter trees are the weaker trees?
      Possibly.

      I'll check some of my local native oaks (Q. garryana) for edible acorns
      again, and if I find something interesting I'll let you all know
      (Jean-Claude, have you sampled any? there should be some in your area as
      well). Perhaps there are some better trees (better, that is, from the
      point of view of a human). Oaks are only a part of the climax forest in
      these parts, and a small one, so the sample size is small. Perhaps some
      Q. ilex imports will be necessary for a starting point instead;
      according to reference books they will grow here.

      I have another idea towards edible forests, but it belongs in another
      post.

      Stephen
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