The Queen Sirikit Botanical Gardens      Not too far from the city of Chiang Mai, you can find this spectacular botanical garden.      The road to Samoeng that winds up the Mae Sa Valley was only completed in the 1980's, before then the journey could only be made in a 4-wheel drive jeep in the dry season. There had, however, been Thai villages scattered up the valley for over a hundred years, growing tea. There were hill tribe villages, teak-logging camps and in the 1930's Dr Kerr started a small botanical garden, as is the wont of Englishmen abroad.      The Queen Sirikit Botanical Gardens, based on this earlier one, were opened in 1992. The gardens cover an area of some 3500 rai and include a wide variety of vegetation ranging from dipterocarp to hill evergreen forest containing over 10,000 trees as well as ferns, palms, herbs and flowers - many of which are extremely rare. The gardens are working with Kew Gardens to become a regional centre and contain research facilities, accommodation for students and an information centre, well stocked with books and facts about the gardens.      Even if you are not a botanist it is well worth visiting these beautiful gardens in the mountains and wandering along the nature trails that wind beside tinkling streams and under great shady trees. The flowers are especially colourful in the cool season which runs from November to March.      There are regular tours to visit the botanical garden as well as surrounding tourist attractions in the Mae Sa Valley.