Lumberjack

In A Link to the Past, the Lumberjacks can be found to the north of Kakariko Village. Two of them are found cutting a large tree saying that they can feel something odd about it. Later on in the game, after facing Aghanim (for the first time), they stop cutting the tree, and if you charge into it with the Pegasus Boots, a hole will appear. When you fall down the hole, you end up in a cave with a Piece of Heart in there.

The Riddle Quest can be started in the Lumberjack's house.