The term 'Tree in a Tray' is a type of Japanese art form known as Bonsai. Bonsai is the practice of cultivating miniature trees in containers, such as trays, to create an aesthetically pleasing and balanced landscape. The art form has been practiced for centuries and is considered a form of meditation. Bonsai trees are often pruned and shaped to create a desired look, and can be kept indoors or outdoors.