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本文从历史植物地理学的角度、根据川西南山地冕宁县沉黄沼泽地层中发掘出中全新世以来保存完好的大量古森林遗迹资料，通过多学科综合性研究证实，中全新世“沉黄古森林”距今约７０００多年，是由４４科、５５属、７３种森林植物组成，以铁杉为主要建群种，林内混生有多种常绿和落叶针阔叶树种。从该森林的演变和种类组成变化得知，在距今４５００年～２８００年间，铁杉和阔叶树种数量减少，云南松数量增加，杉木已从森林中消失；距今２８００年后铁杉进一步减少，云南松显著增加，黄杉、华山松、油杉、桦木、木荷、桤木逐渐从森林中消失；距今２０００年左右，铁杉和雪松从森林中消失。目前该地区森林已演变成云南松林或松栎混交林。森林生态环境演变大致分为４个阶段：（１）温暖多雨阶段（距今７０００年以前）；（２）温暖湿润阶段（距今７０００年～４５００年）；（３）温暖潮润阶段（距今４５００年～２８００年）；（４）温暖干燥阶段（距今２８００年以来）。由上可见，沉黄中全新世古森林及生态环境的演变，提供了这一森林生态系统在时间和空间上物种多样性变化的实例。
Based on the history of phytogeography, a large number of preserved ancient forest ruins have been excavated from the sediments of the Huanghuang Marsh in Mianning County, southwest mountainous area, Sichuan Province. Based on multidisciplinary comprehensive studies, it is confirmed that the Mid-Holocene “ Forest ”is about 7,000 years ago. It is composed of 44 families, 55 genera and 73 species of forest plants. With hemlock as the main species, there are many evergreen and deciduous broad-leaved species in the forest. Based on the evolution and species composition of the forest, we know that the number of hemlock and broad-leaved species decreased and the number of Pinus yunnanensis increased during the period from 4500 to 2800 years ago, and that of fir has disappeared from the forest; the hemlock further decreased after 2800 years , The Pinus yunnanensis increased significantly, and Douglas fir, Pinus armandii, Oleander fir, birch, Schima superba and alder gradually disappeared from the forest; about 2000, hemlock and cedar disappeared from the forest. At present, the forest in this area has evolved into a pine forest or pine-tree mixed forest in Yunnan. The evolution of the forest ecological environment can be divided into four stages: (1) Warm and Rainy Stage (7000 years ago); (2) Warm and humid stage (7000 to 4500 years ago); (3) Warm and humid stage 4500 ~ 2800 years); (4) warm and dry stage (dating back 2800 years since). It can be seen from the above that the evolution of the mid-Holocene ancient forest and its ecological environment in Shenhuang provides an example of the changes of species diversity in time and space in this forest ecosystem.