Species composition of communities are firstly affected by environmental filtering where species are progressively selected from the available species pool, and then by spatial aggregation which result in specific spatial organizations. However, the hierarchical effects of these processes across spatial scales are poorly understood. Using dataset of forest plots in northeastern China, we quantified the effects of environmental filtering at region-zone, zone-area, area-district, district-plot scales, and spatial aggregation at within-plot scale on β-diversity along latitudes. We showed that the patterns of β-diversity was mainly dominated by the processes at the region-zone, district-plot, and within-plot scales.We also showed that environmental filtering at the broader scales had stronger effects at higher latitudes, while at the finer scales only at lower latitudes. The effects of spatial aggregation were more prominent at lower latitudes. We highlight that the scale-dependency of the ecological processes needs to be fully considered in future studies.