关键词: 国外松, 衰退病, 环境条件, 林分因素, 数量化分析, 螺旋图

Abstract: The species and amounts of Cladocera in various water areas of Tianjin district, as well as the ecological distribution, components of species and quantitative variations of Cladocera in salty fresh water and polluted water areas are investigated and discussed by the author.

Key words: Exotic pines, Decline diseases, Environmental condition, Forest stand factors, Quantitative analysis, Spiral chart