1) Arbor Day planting 2) Baby tree 3) Future tree 4) Grove youngster 5) Nursery youngster 6) Small palm 7) Tree 8) Young tree 9) Youth 1) Sprout 2) Tree 3) Treelet 
young tree (E, 179)
• (n.) A young tree.
A very young tree.
Strong, young tree, the stem of which has normal branch development from the bottom up. ... Woody vegetation between 0.4 and 5.0 inches in diameter at breast height and greater than or equal to 20 feet in height, exclusive of woody vines. ... (09 Oct 1997) ... 
A young tree, larger than a seedling but smaller than a pole.
young tree (E, 179)
A young tree that measures two to four inches in diameter.
sap'ling noun A young tree. Shak. 
[n] - young tree
noun young tree
Obtained by destroying (or waiting for Leaves to decay after chopping it down) the Leaves on a Tree. Saplings can be planted anywhere as long as it's on grass, but they need sufficient light and room to grow or they will stay a Sapling forever. Destroying a planted Sapling will give it back to the player.
a tree at least 4 1/2 feet tall and up to 4 inches in diameter.