The Collaborative International Dictionary of English v.0.48:

sapling \sap"ling\, n.
   A young tree. --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sapling
    n 1: young tree

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "sapling":
   adolescent, baby, conifer, evergreen, fledgling, fruit tree,
   hardwood tree, hopeful, infant, junior, juvenal, juvenile, minor,
   pollard, pubescent, scion, seedling, set, shade tree, shoot, slip,
   softwood tree, sprig, sprout, stripling, sucker, teenager, teener,
   teenybopper, timber, timber tree, tree, twig, young hopeful,
   young person, younger, youngest, youngling, youngster, youth