Root trapper bags are a plastic type material on the outside and a coarse fabric on the inside that prevents the roots from J hooking and winding around the outside of the container - as I'm sure you've seen in many plants grown in plastic pots. As far as the Walmart chestnuts, I started with 6 of those 3 years ago and 3 of them died the 1st year, After that I decided to grow my own. I've since planted 40 -50 and only lost a handful and the ones I started from seed have caught up to the Walmart trees in growth. I like my results better. They say 3-5 years but I don't fertilize or do anything special with them so I would expect closer to 5-7 years.