Make a jig by cutting the windscreen shape in a 1x4. Cut two lengths of chair cane, soak them in water for several minutes then clamp them in the jig. Using the jig to support them glue the pieces together to form the upper and lower parts of the windscreen frame.

The chair cane does not hold its shape very well. I recieved a suggestion that bamboo would make a good frame. Heating it over a soldering iron will make it bendable. I'll update here when I try it.