Hoops could be laminated up out of just about any wood that is available in your area, but you would need a table saw to make the thin strips. Since it might take an hour to fabricate each hoop, this is not a great solution.

Eric,

For a hoop foundation we use use 20 inch lengths of rebar driven halfway into the local heavy clay. The pvc slips over the rebar. I've not heard of pvc leaching into the soil although it does create pollution in its manufacture and ultimate disposal. 10 foot pieces make hoop frames. 20 foot pieces make walk-in greenhouses. I use a pair of 1x2's along the ridge for stability. These can be used with metal cable clamps or with duct tape.
Bridging the gap between wire and rebar is the bar stock.
If you have access to a small welder it's easy to tack together 3/16" or 1/4" bar stock for smaller frames. Bar stock is avalable in 20 foot lengths and is easy to bend for hauling. Many junk yards sell this as 'new' metal.

Mike