A few years back, I made a tree skirt for DD whose 12 ft tree has a diameter of 82+". It was simple because her tree is so wide and the branches start so low that an elaborate tree skirt would have been a waste- her words. Just a circle with four sections and two alternating fabrics. On the back I used a wide backing muslin. My neighbor bought one just last month- same 12 ft height but the diameter is much smaller at less than 60". Your cousin may provide you with some insight! Good luck and keep us posted.