Big pieces of bark for terrain?

[andes]

I've seen several basing/terrain videos and tutorials where large chunks of bark are painted up and used as boulders. I've checked Amazon and the local garden center and can't find anything that large -- the biggest I can find are ~1" or so long, and I'm looking for two to three times that size. Have you used this technique? If so, where did you find the raw materials?

[Bung]

You need to look for Cork bark or cork Tube for pets.

 

[gideon stargreave]

Go out to the park or woods and have a rummage. Councils also often use bark for planting flowers.

in my experience, pines have the best bark. Someone else already mentioned cork trees too, which you can get from pet shops and garden centers for really cheap

[Urauloth]

Pet stores and model railway suppliers are where most people get theirs. It can be hard to find, though, it took me years to luck into some in the size I wanted.
If you can only get it in smaller sizes, though, you can always stick it together to make bigger rocks if you need to. Cork's pretty good tempered, especially if you seal it with PVA.