Painting wood with green slime

I replaced some wood on a camping trailer last year. I never got it painted. It's been under a tree all year. Now this new wood has a green slime or green (something) on it. [What is it?].
Do I need to sand this all off the wood, or can I just scrub it with bleach, or can I paint right over it? I plan to use an oil based paint.
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It's probably penetrated the wood. Replace the wood and paint it immediately this time. You could try cleaning it bleach, but you'll probably have a tough time knowing if the wood is still in good shape beneath the visible surface.
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snipped-for-privacy@hotmail.com wrote:

It's most likely moss along w/ other "stuff" that tends to fall from trees... :)
Yes, you'll need to remove it down to bare wood to have any hope of paint staying on it for more than about 15 minutes.
Power washing and oxalic acid (wood bleach, one of the common deck cleaners), then whatever other cleanup that leaves. Sand it some to get a good surface for adhesion. Obviously, let it dry thoroughly before painting.
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snipped-for-privacy@hotmail.com wrote:

Moss/algae...same stuff that grows on the north side of trees. ___________

Kill it with bleach, rinse, let dry. If any residue remains, scrape or sand off. Prime. paint.
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dadiOH
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