Quaking Aspen (Populus tremuloides), Poplar (P. deltoides and fremontii), Cottonwood (P. trichocarpa and hyb.) and various Willow species (Salix spp.) are all members of the Populus genus in the Salicaeae, or Willow, family, with 56 genera and about 1,225 species in all.🌿 The quaking aspens are fast-growing, short-lived, upright, branching, open, deciduous trees that typically grow in colonies of identical trees that may live thousands of years. Their clone offspring form new trunks that sprout