> A lot of these pressurized timbers are treated with either CCA (chromated
> copper arsenate), followed by ACZA (ammoniacal copper zinc arsenate) and
ACQ
> (ammoniacal copper quat). All three preservatives are waterborne
> preservatives. These timbers shed their contents very slowly and have been
> applauded for limiting cutting of forest products since they last a lot
> longer than untreated timbers. Some gardeners are cautious about using them
> around food producing plants.
>
> As of January 1, 2004, EPA will not allow CCA products to be used to treat
> wood intended for any residential uses such as play-structures, decks,
> picnic tables, landscaping timbers, residential fencing, patios and
> walkways/boardwalks.
> http://www.epa.gov/pesticides/factsheets/chemicals/cca_transition.htm
>
> Should we use them where they might bleed into a pond? I also wonder if we
> should be tossing them into compost piles. :)
>
At the risk of being off topic when I was young and not quite as eviromentaly
aware I used lots of pressure treated wood. All of it is still around. I use
it for various things but I never throw it away. Mostly because of the
possible bleed into the environment. (which occurs not matter what anyway.) I have
pieces 6" long and several 16' feet long. If I needed to us rot proof lumber
that would come into contact with the environment now I would use cypress.
Cypress comes very close to being as good as pressure treated (I have a slab of
natural cypress that has been dug out of swamp that has to be several hundred
years old) Around here a non treated piece of wood doesn't last but a few weeks at
most. A few days laying on the ground will show termite damage on most wood.
I'm not sure about redwood. but cypress is almost wood everlasting! They make
log homes out of it that do not have to be treated for termites.
Moon
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