Horticultural therapy (also known as social and therapeutic horticulture or STH) is defined by the American Horticultural Therapy Association (AHTA) as the engagement of a person in gardening and plant-based activities, facilitated by a trained therapist, to achieve specific therapeutic treatment goals. The visual aesthetics of plants are known to elicit feelings of inner peace, which generates positive emotions toward a meaningful appreciation of life. Direct contact with plants guides the individual's focus away from stress enhancing their overall quality of life. The AHTA believes that horticultural therapy is an active process which occurs in the context of an established treatment plan. Horticultural therapists are specially educated and trained members of rehabilitation teams (with doctors, psychiatrists, psychologists, occupational therapists and other) who involve the client in all phases of gardening, from propagation to selling products, as a means of bringing about improvement in their life.