Pete and Charlie:
My parents pulled the glider out of the woods some years ago and restored it. I am not sure what type of wood was on the original or on the restoration. The glider started to get ratty again and was placed in the edge of the woods a second time. Ants and termites took up residence and the wood was reduced to virtually nothing. Certainly nothing that you could or would want to make a pen out of. I decided to go with the plastic lumber in the hopes that the glider's third life would be its longest one yet.