Mottling on bamboo: What is it?

[Mark Meckes]

I collected some aged and standing dead bamboo from groves in Savannah Georgia in 1990, and what I have enjoyed about using this bamboo is the beautiful mottling on the outer surface of the bamboo.

I was told that it had to do with the high humidity of this region. This doesn't happen in dryer areas?

Does anyone know what causes this?

Is it a type of spore-ring growth?
I saw small pieces of `Spanish moss and lichens growing on the bamboo when I was there.
Is it possible to make this happen on bamboo in a controlled method?
It makes very beautiful designs, and works that I've made for sale that incorporate these designs, often sell before plain bamboo.


Pictures:
http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-111f.jpg Mottling on bamboo (http://www.bamboocraft.net/workshop/showphoto.php?photo=598)
Phyllostachys bissetii, Savannah Georgia, USA
Unfinished culms. Size dia to 1 1/2 inches(to 3+cm)

http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-112f.jpg Closeup (http://www.bamboocraft.net/workshop/showphoto.php?photo=599)
Untouched surface of Phyllostachys dulcis, Savannah Georgia

http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-113f.jpg Close-up. (http://www.bamboocraft.net/workshop/showphoto.php?photo=600)
After buffing waxy surface with a nylon scour-pad. Phyllostachys dulcis, Savannah Georgia

http://www.bamboocraft.net/workshop/data/2/thumbs/1Mvc-118f.jpg Every culm has a tale to tell (http://www.bamboocraft.net/workshop/showphoto.php?photo=601)

[BlueGreyFog]

You're right. That mottling comes from excessive moisture being around and it is in the mildew family.

[newbambooerman]

that does look neat. however, could this be be bad if it were blowtorched later (the possibility of some sort of mold being fired up?), or perhaps make it deteriorate faster?