The sediments of a small lake in Yunnan (22?N, 100'30'E, 1280 m a.s.l.), although presenting substantial dating problems, are lnost probably 36,000-20,000 years old. The potential natural vegetation of the locality today is subtropical evergreen broadleaved forest, but tropical rainforest occurs only 30-60 km away and 600 m lower; Pinus forest occupies poorer soils down to 1250 m a.s.l. The pollen diagrams demonstrate that subtropical broadleaved forest and pine forest grew around the site during the sedimentation period fluctuating in their relative abundance. In addition there were short intervals in which Podocarpaceae (including Dacrydium not now growing in mainland China) were common. Another site, 7.5 km away, confirms this record. The climatic implication is that, at a time approaching the last glacial maximum, this part of China experienced greater winter humidity and rainfall but mean annual temperatures only slightly, if at all, lower than present.
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Jin-ling et al. (1986) studied this question.