How to hire and arborist who can help one in selecting and planting a high-quality tree that will thrive in your landscape; Properly pruning your trees to enhance their appearance, health, and safety, and orchestrating their removal safely and efficiently when needed; Diagnosing and treating tree disorders such as diseases, pests, soil fertility problems, and physical injuries; Preserving trees during construction activity and preparing them for extreme weather such as wind, ice, and lightning; Evaluating tree structure, assessing hazardous conditions, and recommending actions to mitigate risks. Virginia, like many states doesn't license aborists. The best way to discern a competent arborist is to ask if the individual has earned the credential of “Certified Arborist”, which is awarded by the International Society of Arboriculture (ISA) — a professional organization whose mission is to advance the ethical and scientific care of landscape trees. To become a Certified Arborist, a candidate must first meet minimum education and work experience requirements and then pass a written competency exam. Once certified, the arborist must participate in continuing education programs to maintain his or her certification