They look to be horsehair alone mounted on an MDF base. The very lower part has been cut in and painted brown, perhaps with a paste added. Everything else looks flocked with a multi coloured fine flock. They are very rigid, no springy horsehair, so perhaps have been given several applications of a PVA based glue - like Woodland Scenic cement. These are made by S&A Scenics and are the the large set.