Bonsai is the Japanese art of growing miniature trees by restricting the growth of the plant through various pruning and cultivating techniques. As part of the growing technique (aka the training process), future Bonsai trees are grown in containers/trays to limit root growth and provide easy access for pruning or shaping the plant as desired. The Bonsai method can take years before a final tree is completed and requires constant care for the tree to stay in the desire size and shape. Bonsai trees are often confused with dwarfism or dwarfing of trees. In actuality, the two processes are completely different in their approach to creating miniature trees.
In dwarfing, the miniature tree effect is obtained through genetics or selective breeding. In selective breeding, specimens which are smaller than the normal specimen size are mated to created a smaller than average specimen. This process is continued till you have a breed of the specimen at the desired size. The other method for dwarfism in plants is genetic engineering. In genetic engineering, genes that inhibit growth or provide miniature characteristics are spliced into the genome of the desired specimen. Genetic engineering modifies genes on a microscopic level while selective breeding modifies genes looking at the macroscopic effects. The end result is a miniature version of the desired specimen with all the desired aesthetics retained.
Depriving a plant of specific hormones during the growth process can also result in dwarfing of the specimen. However, the lack of hormones can result in the dwarf specimen not displaying some of the desired aesthetics or size. Practice or experience is the best the way to control the end result when using the hormone approach. For the purposes of creating display miniatures trees, the hormone method is not normally used.
Both the Bonsai art form and dwarfing are ways of growing many different miniature species of plants and trees. Whichever process is used, the end result is a miniature version of a larger tree or plant. At this point, the dwarfed tree/plant has some significant advantages to a Bonsai tree. Once the dwarfed tree is developed to the desired size, there is little maintenance (i.e. watering, removing dead branches, etc...) required to sustain the tree. However, the Bonsai tree will require continuing pruning and cultivation to maintain the desired size and shape. If not properly, this can result in the death or ruination of the Bonsai tree. The Bonsai tree method is essentially a larger commitment of time and resources.
So, if the desired miniature tree is one the can be taken care of with watering and some general maintenance, a dwarf tree is the proper selection. However, if you want a miniature tree that reflects your personality and want a hobby for life, the Bonsai tree is the proper selection. In either case, miniature trees have been a source of beauty and awe in private gardens and public arboretums for decades and will add a definitive touch to any decor.