To start you will need tissue paper in an array of seasonal leaf colors (white for snow) Construction paper for the base and we used construction paper to cut out the tree trunk and branches. I cut out the trees ahead of time and glued them down to the paper since my kids were a little young to make the tree shape but if your kids are older then they can cut it out and glue it down so you have a base to work with.
Then for my kids favorite part, tear small pieces of tissue paper and crumple them up. Rub each piece with the glue stick, or dip it in glue. Both my 5 and 3 year olds were over joyed to rip and crumple paper.
Using different colors to create the different seasons, we used white and silver for the winter snow, pink for the spring blossoms, green for the summer leaves, and yellow and orange for the fall leaves.