Great Oak Tree

The Great Oak Tree is a common landmark of the Smurf Forest where the Smurfs would resort at certain occasions. Gargamel often uses the Great Oak Tree as a waiting point as well, knowing that the Smurfs often appear there.

Mainstream Smurfs Media
In the Season 6 episode "I Smurf To The Trees", it is revealed that Grandpa Smurf planted the acorn that would grow up to become the Great Oak Tree.