云南热带森林植被分类纲要

A sketch for classification of tropical forest vegetation in Yunnan

关键词:  植被, 分类, 森林, 热带, 云南

Key words:  vegetation, classification, forest, tropical area, Yunnan

摘要:

热带森林是云南的重要植被类型, 虽对云南热带森林植被的系统分类及研究在《云南植被》中有所体现,并发表了大量论文,但在植被类型的划分、命名及其解释上却不尽相同,特别是对群系的记录很不全面。该文总结已掌握的研究资料,参考世界类似热带森林植被的研究成果,系统地对云南热带森林植被的类型、分类、物种组成和群落特征等进行了归纳。结果表明:云南的热带森林植被包括3个主要的植被型, 即热带雨林、季雨林、季节性湿润林。云南的热带雨林是在亚洲热带北缘季风气候下发育的在水分、热量和分布海拔上均到了极限条件的热带雨林类型,分为热带季节性雨林和其山地变型—热带山地雨林二个植被亚型, 前者包括19个群系, 后者包括12个群系。文中的热带季雨林是依据其原始定义指介于热带雨林与萨王纳之间的一种热带落叶至半常绿森林植被,其分布主要受水分条件制约,非纬向地带性植被; 它们分为落叶季雨林和半常绿季雨林2个植被亚型,前者包括7个群系, 后者包括3个群系。 把分布于云南南部石灰岩山地的在一些植物学文献中称之为“石灰岩季雨林”的热带森林植被,考虑其常绿至半常绿的外貌特征、特殊的植物区系组成以及乔木层没有一个明显的无叶(落叶)期(其落叶现象可能主要由于局部生境的干燥和历史的原因,并非是由于地区性气候干旱所导致),它们与季雨林的原始定义不符; 该文使用名称热带季节性湿润林来定义这类发生在石灰岩山中、上部,在热带季节雨林带之上的热带山地垂直带上的植被类型。季节性湿润林也分为季节性常绿湿润林及季节性半常绿湿润林2个植被亚型,各包括2个群系。

Abstract:

Tropical forests are important vegetation types in Yunnan. Although fundamental work was enumerated in the monograph Vegetation of Yunnan and a lot of papers on local vegetation types were published, the classification, termilology and explanations on the tropical forest of Yunnan are still various and uncertain, especially on the classification and circumscription for formations of the forest. This article is a summary on the classification of the tropical forest vegetation types and their formations recorded in Yunnan. The tropical forest vegetation in Yunnan includes three main vegetation types: tropical rain forest, monsoon forest and seasonal moist forest. The tropical rain forest in Yunnan is a type under the monsoon climate and evolved at the limits of rainfall, temperature and altitude required by tropical Asian rain forests. The vegetation type is comprised of the seasonal rain forest on lowlands and the montane rain forest on higher elevations as two subtypes, and the former includes nineteen formations and the latter includes twelve formations. The tropical monsoon forest is a deciduous to semi-evergreen vegetation type between the tropical rain forest and the savannas on its original definition, and its distribution is controlled mainly by rainfall and topography. The tropical monsoon forest is classified into two subtypes: the deciduous monsoon forest with seven formations, and the semi-evergreen monsoon forest with three formations. The so-called “the tropical monsoon forest on limestone” in some Chinese references, due to its evergreen to semi-evergreen physiognomy, particular floristic composition and not having a deciduous period of the year in its canopy(deciduous trees in the forest could be due to local habitat dryness and historical reasons on limestone, not the regional dryness of climate), does not meet the definition of the monsoon forest. Here I give the name the tropical seasonal moist forest for this type of forest occurring on limestone slopes above the tropical seasonal rain forest at valleys. The tropical seasonal moist forest is also assorted into two subtypes: the seasonal evergreen moist forest and seasonal semi-evergreen moist forest, and both of them include two formations.