The American Society of Consulting Arborists (ASCA) is for arborists who consult or are seeking out a career in consulting.  ASCA has developed the highest standards of performance in the field of arboricultural consulting and is the only professional or trade organization dedicated solely to the advancement of the arboricultural consulting industry and its members.  ASCA is the preeminent authority on the issues and practice of those who are Consulting Arborists.

The ISA – International Society of Arboriculture is an educational organization that disseminates information about trees based on scientific research.  It has a tree worker and arborist certification program and can help you locate a certified professional in your area.  The ISA also offers numerous educational publications.

The Western Chapter of the ISA is the branch that includes California, Arizona, Nevada, and Hawaii.

The Tree Care Industry Association (TCIA) provides training and safety programs, among numerous other programs, that help tree care businesses with their everyday challenges.