Screw a 2x4x12" board into the center a 16"x16" base. Slide the carpet tube over the base as shown. You will also need an umbrella base. I happened to have a broken one on hand.
Cut the bottoms off of paper lunch bags. My carpet tube is measured at 5 1/2 feet. It used 36 paper bags. I have a taller palm tree in my classroom (about 6 1/2 foot)..it took about 50 bags. Scrunch the bags down to get the textured look. See example. Using your umbrella base, hot glue the palm leaves starting at the top. Continue working around the tree, gluing each leaf down. Last, stick your umbrella handle into your tree.