World Botanical Tour Guides of Great Britain

World Tour Guides: One of the Great Royal Botanic Gardens is located in Kew, usually referred to as Kew Gardens. It is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. The Royal Botanic Gardens, Kew and the brand name Kew are also used as umbrella terms for the institution that runs both the gardens at Kew and Lakehurst Place gardens in Sussex. The Royal Botanic Gardens, Kew, a non-departmental public body sponsored by the Department for Environment, Food and Rural Affairs, Kew is responsible for the world's largest collection of living plants. The living collections include more than 30,000 different kinds of plants, while the herbarium, which is one of the largest in the world, has over seven million preserved plant specimens. The library contains more than 750,000 volumes, and the illustrations collection contains more than 175,000 prints and drawings of plants.

Kew Gardens originated in the exotic garden at Kew Park formed by Lord Capel John of Tewkesbury. It was enlarged and extended by Augusta; some of the early plants came from the walled garden. The collections grew somewhat haphazardly until the appointment of the first collector, Francis Masson, in 1771. In 1840 the gardens were adopted as a national botanical garden. The first curator was John Smith. The Davies Alpine House opened the third version of an alpine house since 1887. Although only 16 meters long the apex of the roof arch extends to a height of 10 meters in order to allow the natural airflow of a building of this shape to aid in the all important ventilation required for the type of plants to be housed.

The new house features a set of automatically operated blinds that prevent it overheating when the sun is too hot for the plants together with a system that blows a continuous stream of cool air over the plants. The main design aim of the house is to allow maximum light transmission. To this end the glass is of a special low iron type that allows 90% of the ultraviolet light in sunlight to pass. It is attached by high tension steel cables so that no light is obstructed by traditional glazing bars. To conserve energy the cooling air is not refrigerated but is cooled by being passed through a labyrinth of pipes buried under the house at a depth where the temperature remains suitable all year round. A design goal of the house is that the maximum temperature will not exceed 20 degrees Celsius.

Kew's collection of Alpine plants (defined as those that grow above the tree-line in their locale - ground level at the poles rising to over 2000 meters in the Alps), extends to over 7000 and as the Alpine house can only house around 200 at a time the ones on show are regularly rotated. Kew Palace is the smallest of the British royal palaces. The Palm House (1844–1848) was the result of cooperation between architect Decimus Burton and iron-founder Richard Turner, and continues upon the glass house design principles developed by John Claudius Loudon and Joseph Paxton. A space frame of wrought iron arches, held together by horizontal tubular structures containing long prestressed cables, supports glass panes which were originally tinted green with copper oxide to reduce the significant heating effect. The 19m high central nave is surrounded by a walkway at 9m height, allowing visitors a closer look upon the palm tree crowns.

A new treetop walkway opened on 24 May 2008. This walkway is 18 meters (59 ft) high and 200 meters (660 ft) long and takes visitors into the tree canopy of a woodland glade. Visitors can ascend and descend by stairs. The floor of the walkway is made from perforated metal and flexes as it is walked upon. The entire structure sways in the wind. The image to the left shows a section of the walkway and the steel supports that were designed to rust to a tree-like appearance to help the walkway fit in with its surroundings. Kew Explorer is a service that takes a circular route around the gardens, provided by two 72-seater road trains that are fueled by Calor Gas to minimize pollution. A commentary is provided by the driver and there are several stops.