I like this moss tank BUT what is this stuff?

[Crystalview]

I can not identify the wood or rock on the back wall. I like the look of the first few pictures that have not grown in yet. What is the brown stuff the moss is growing on? In "Tank" it says's its roots could that be right?
I would like to find away to mount moss or nana anbias up on the wall, without taking up a lot of space. Have any other Idea's on how I could do this

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http://www.aquarminy.yoyo.pl/ang/galeria.html

[mithrius]

it looks like rock.... but i bet big flat pieces of driftwood of somesort would work well! you could also build a makeshift shape out of that mesh stuff ppl use to build moss walls, and just wing the shape with anything that gets the shape u need (like popcicle sticks? more driftwood?)
once the moss grows over it, you wont see anything behind!

[Crystalview]

I was just at Tom Barr's and he showed me his wood pile, Nice stuff! He has some planks of raw cork that I can shape like that. I can't wait to play with it.
While there Tom showed me a pile of manzanita driftwood he is sending to Canada. He told me how a lot of you are short of wood to use. I am just finding native wood and plants in the mountains I live in. It adds a whole new dimension to my hobby.