Spatial distribution patterns of seedling and sapling in a spruce-fir forest in the Changbai Mountains area in northeastern China

The objective of this study is to describe the seedling and sapling distribution patterns of a spruce-fir coniferous and broadleaved mixed forest in the Changbai Mountain area, one sample plot covering 60x60 m was established. The spatial coordinates, diameters at ground height (DGH) and heights (H) of all trees with a height exceeding 30 cm and a diameter at breast height (DBH) less than 5 cm were measured. The following 15 tree species were recorded in this plot: Abies nephrolepis, Picea asperata, Pinus koraiensis, Betula platyphylla, Betula costata, Tilia amurensis, Acer tegmentosum, A. mono, A. ukurunduense, Populus davidiana, Phellodendron amurense, Taxus mairei, Quercus mongolica, Fraxinus mandshurica and Ulmus japonica. Abies nephrolepis and Tilia amurensis, and Picea koraiensis and Tilia amurensis, do not show a positive spatial correlation; The spatial relationship between Abies nephrolepis and Picea koraiensis, and Abies nephrolepis and Pinus koraiensis is not negative; There are no obvious spatial correlations between Picea koraiensis and Pinus koraiensis.