Plusea (Hannah) and I came up with this handy little hack when planning design workshops in the wilderness of Madagascar. When doing participatory design projects, it's often super handy to have big surfaces on which one or more people can collaborative draw and share ideas visually and textually. Usually you can just get a big pad of paper, or butcher paper and some markers!

If you want to do the workshop during an intense backpacking adventure in the jungle, there's some limitations you run into though!

Paper gets wet and heavy!
You create lots of garbage you have to carry (If your paper is not resusable)

Hannah suggested something along the lines of the Betabook, https://www.kickstarter.com/projects/betabook/beta..., where we could have re-usable surfaces. A problem with dry-erase though would be

gross fumes (i hate the smell of those)
non-durability (they smudge easy)
Markers can dry out, or get screwed up by water

Eventualy we came up with the idea of using Chalk pens! They work great!

Pros:

No gross fumes.

Durable, don't smudge when tossed in your backpack.

Easy clean! Just dump water on it!

Lightweight! Use thin plastic, or materials nearby like leaves and rocks and tarps!

High Contrast! Lots of good cheap colors to choose from!

Step 1: Materials and How to Use

Materials

Chalk Pens http://www.amazon.com/dp/B006Y1SZY2/ref=sr_ph?ie=U...

Thin Cutting Boards: http://www.amazon.com/CounterArt-Flexible-Cutting-...

How to Use

This is pretty dang straight-forward.

Use chalk pens.
Draw on Stuff.
Rinse off with water!

Step 2: Alternate Materials

These Chalk pens are pretty awesome! They write really well on a number of different surfaces! If you run out of boards, you can use things like

big leaves in the jungle!
Side of your Tent!
Rocks!

It worked for us in the jungle!

I think it should be decently eco-friendly. The Markers are mostly chalk. I don't know what the pigments are, but hopefully they aren't too bad. If you are worried about this, maybe stick to the white non-colored pens.