Multiattack. The giant makes two attacks, using Tree Club or Trash Lob in any combination.
Tree Club. Melee Attack Roll: +8, reach 10 ft. Hit: 18 (3d8 + 5) Bludgeoning damage. If the target is a Large or smaller creature, it has the Prone condition.
Trash Lob. Ranged Attack Roll: +8, range 60/240 ft. Hit: 16 (2d10 + 5) Bludgeoning damage, and the target has the Poisoned condition until the end of its next turn.