Yunnan Province is one the least economically developed areas of China and is located in the far west, sharing borders with Burma Laos and Vietnam. It is a major source of a number of essential oils, including geranium, medicinal eucalyptus, citronella and wintergreen, for which Yunnan holds a major share of the international market. Annual production numbers are presented in Table 1.
The production and trading systems for essential oils in Yunnan changed during the 1990s in response to the impact of the economic reform program and a number of other factors.
Location and the system of production: Prior to 1990, production of geranium oil was undertaken in several areas in Yunnan. Today, however, the comparatively remote Binchuan Valley has become the pre-dominant source. The county of Binchuan lies to the northwest of the provincial capital, Kunming, at an altitude of 1,450 m above sea level. The climate is dry in summer and moist in winter but without distinctive four seasons; the annual rainfall is around 582 mm. The combination of climate and soil are ideal for cultivation of geranium. The population of the county is around 300,000, of which eighty percent grow geranium.