To study ecology of Korean native wild orchids, Cymbidium kanran and Cymbidium lancifolium distributed in Mt. Halla, Jeju-Do, Korea were surveyed their growth conditions in various habitats, including seasonal changes of air temperature, maximum and minimum values of the air, soil temperature at depth of 20㎝, relative humidity, monthly fluctuations of light intensity, soil acidity, topograpical features, wind speed, etc. from June 1977 to June 1980.
Air temperature was ranged to be 8℃∼15.5℃ in spring, 21.1℃∼24.9℃ in summer, 11.5℃∼20.7℃ in autumn and 5.5℃∼8.5℃ during the winter season. Thus, the annual air temperature of the Cymbidium sites showed a range of 12℃∼17℃ as an average.
Minimum value was recorded -6℃ on January, and maximum value was measured 31℃ on August.
The highest soil temperature at depth of 20㎝ was about 23℃ in August; on the other hand, the lowest was 4.4℃ in January for this regions. The range of annual mean soil temperature showed between 12℃ and 14℃ according to the altitudes of surveyed area.
As to the monthly distribution of light conditions January, February, March, October, November and December were maintained higher light intensities ranged from 8,000 to 10,000 lux, and May, June, July and August were shown lower light regimes ranged from 1,500 to 2,500 lux. Also, April and September regarded as an intermediate were recorded to he range of 5,000∼6,500 lux. Annual average light intensity was about 6,500 lux for Cymbidium habitats in comparison with 110,000 lux in open area of a clear day. Therefore, one must be suprised that Cymbidium grow at the light condition of 6% of full sunlight in nature. Annual relative humidity was from 77% to 83% in average, and autumn and winter were regarded as a dry seasons; however, summer seemed to be a humid period.
The range of soil acidity was from pH 5.1 to 5.7 in the Cymbidium positions.
Natural distribution areas of the Cymbidiums were observed more abundantly on the south-facing of eastern south-facing slopes having a breeze in general.
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