If you are wondering how to wrap trees with Christmas lights, there are some basic measurements that you need to take into consideration. Measure the circumference of the tree trunk, as well as the circumference and count of any branches you wish to wrap with lights. Determine how much spacing you want both between each light bulb on the string, as well as how far apart you plan to wrap the light strings. Here are 30 Beautiful Christmas Lights Decorations on Trees.