Tree climbers may need a high school diploma or GED certificate, depending on the requirements of the employer. You should have excellent tree climbing skills and completely lack an aversion to heights. Training, or even an interest, in horticulture, landscape design, or arboriculture can set you apart from other candidates. Some employers may require you have your own tree maintenance equipment. It is imperative you know how to use and maintain the tools you use to trim, inspect, and maintain trees. If your duties include the application of pesticides, some states require you first obtain a special license.