The word arboretum means a botanical collection (etum) of trees (arbor). I like to think of it as a tree museum or zoo. Specimens from around the world may be brought together into one location. An arboretum often features trees that are endemic. Other plants like shrubs may be included, but the main focus is on the trees.
The Design of Arboreta
A common design for arboretums is to make several groups of trees according to different characteristics such as whether they are edible, scented, native, ethnobotanical, conifers, and so on. There may be an area specially created for children.
Since arboretums can also be used as research stations, many are run by universities, such as the Core Arboretum a 91-acre arboretum owned by West Virginia University and located on Monongahela Boulevard in Morgantown, West Virginia. It is open to the public daily without charge. Arboreta can help preserve endangered species and study their genetics, perform experiments and educate the public.
An arboretum specializing in growing conifers is known as a pinetum. Other specialist arboreta include saliceta (willows), populeta, and querceta (oaks), a fruticetum (from the Latin frutex, meaning shrub), and a viticetum, a collection of vines.
The Arboretum as a Botanical Garden
More commonly, today, an arboretum is a botanical garden containing living collections of woody plants intended at least partly for scientific study, but also to inspire curiosity and build knowledge about plants and wooded landscapes in order to enhance life, preserve nature, and advance sound stewardship practices.
An example is the Arboretum, created in 1991 as a joint effort between the University of Kentucky and the Lexington-Fayette Urban County Government. The mission of The Arboretum is to showcase Kentucky landscapes and serve as a resource center for environmental and horticultural education, research and conservation. The Arboretum began in 1991 and boasts 100 acres of year-round color and plants.
Arboreta Through the Ages
Egyptian Pharaohs planted exotic trees and cared for them; they brought ebony wood from the Sudan, and pine and cedar from Syria. Hatshepsut's expedition to Punt returned bearing thirty-one live frankincense trees, the roots of which were carefully kept in baskets for the duration of the voyage; this was the first recorded attempt to transplant foreign trees. It is reported that Hatshepsut had these trees planted in the courts of her Deir el Bahri mortuary temple complex.
One example of an early European tree collection is the Trsteno Arboretum, near Dubrovnik in Croatia. The date of its founding is unknown, but it was already in existence by 1492, when a 15 m (50 ft) span aqueduct to irrigate the arboretum was constructed; this aqueduct is still in use. The garden was created by the prominent local Gučetić/Gozze family. It suffered two major disasters in the 1990s but its two unique and ancient Oriental Planes remained standing.
The Urban Definition
Interestingly, the Urban Dictionary defines arboretum as a place where everybody belongs to a clique (because everyone has labels, like the plants in an arboretum).