The current level cap for Tap Paradise Cove is level 90 and the level cap for Paradise Cove Android is 50. Once you reach these levels you cannot advance further.
Once a player reaches level 60 in the iOS version of the game the interval between levels increases dramatically so it takes longer to level up. Additionally, the trees in the main cove start to yield less xp. To level up more quickly try chopping trees in Pirate Cove or Mermaid Cove as they give more experience.