Hi. Could I start a above ground 4 foot tall, 125 foot long hugelkultur bed as a natural border fence? I live in the city and I already have multiple raised beds made from concrete blocks on my attached vacant lots due to poor soil quality. I've done the lasagna method in my raised beds with success using wood chips, cardboard, etc. The tree trimming companies around here love to give away free wood chips, so asking for logs shouldn't be a problem.