Undergrowth vegetation niche in scenic-recreational forest communities of Platycladus orientalis and Robinia pseudoacacia in Beijing suburb Niche of the Major Tree Species Populations in Cathaya argyrophylla Forest in Guangxi Study on the Niche of the Main Populations in Abies chensiens Community Niche characteristics of dominant populations in natural forest in North Guangdong Niche of dominant species populations in an evergreen broad-leaved forest in Baishanzu Niche of Main Understory Populations of Larix gmelinii Rupr Forest in A’ershan Area The Niche Characteristics of Endangered Plant Tsuga tchekiangensis in Jiulongshan National Nature Reserve of Zhejiang Province