  We used the dendrogram algorithm to decompose the surface density
distributions of stars into hierarchical structures. These structures were tied
to the multiscale structures of star clusters. A similar power-law for the
mass-size relation of star clusters measured at different scales suggests a
self-similar structure of star clusters. We used the minimum spanning tree
method to measure the separations between clusters and gas clumps in each
massive star-forming region. The separations between clusters, between clumps,
and between clusters and clumps were comparable, which indicates that the
evolution from clump to embedded cluster proceeds in isolation and locally, and
does not affect the surrounding objects significantly. By comparing the mass
functions of the ATLASGAL clumps and the identified embedded clusters, we
confirm that a constant star formation efficiency of $\approx$ 0.33 can be a
typical value for the ATLASGAL clumps.
