I recall seeing an article on sugar plantation railroads, where there were photos of cane being harvested. I believe it was in a Narrow Gauge and Short Line Gazette. Photos such as that would give you the relative size, and shape, of the cane, compared to the people harvesting it. You would then have to find a material that best represented the crop. You might try a search on "sugar cane", sugar plantation railroads, etc. to see if you can find that kind of photo.
Unless someone has modeled it before, and can provide some information, that's about the best I can offer right now.
Pete