From the official rules: 
Four rival lumberjacks are competing to chop down the most trees for their business. However, standing in their way are tree-hugging hippies protesting the deforestation.
The following terms are used in Logger:
Tree - Any seedling, sapling or mature tree on the board.
Seedling - A large pyramid
Sapling - A large pyramid with a medium pyramid stacked on it
Mature Tree - A stack of pyramids. From top to bottom: small, medium, large.
Protester - Denoted by a volcano cap
Logger - A piece representing the player. Denoted by a medium pyramid of a color not used for trees. Non-Icehouse pieces like meeples may be also used.
Place a seedling on the center of the board. The remaining pyramid pieces from the Rainbow stash are kept aside in a common pool. Starting with the first player, each player places his logger on a corner of the board. Each player also starts with 1 protester in his or her supply (2 protesters for a 2-player game). Remember who went first as this will be important at the end game.
The winner is the player with the most points at the end of the game. Though scoring 10 points triggers the end game, having 10 points may not be enough for victory.
No Diagonals - Diagonals do not exist in Logger. Any rule pertaining to adjacency or movement is orthogonal only.
Each player's turn consists of three parts: Movement, Growth and Action.
Movement - Move your logger up to two spaces. Loggers may not occupy or walk through spaces occupied by trees or other loggers.
Growth - All trees in the same row and column your logger occupies grow 1 stage. All seedlings become saplings and all saplings become mature trees. Mature trees produce 1 seedling in any space adjacent to them if able. Please note growth of all trees is considered simultaneous, so no tree should experience two stages of growth in one turn, nor should any seedlings newly spawned from a mature tree this turn. All trees in your logger's row and column must grow or create a new seedling if able.
Action - There are three options in the Action phase: Plant, Protest and Chop. You must perform an action if able. This phase is skipped if your logger is unable to perform any action.
Plant - Plant one seedling in any space adjacent to your logger.
Protest - You may place one or more protesters from your supply onto mature trees. Protested trees may not be directly chopped down by any player.
Chop - Chop down an unprotested mature tree adjacent to your logger by removing it from the board. Chopping will create a domino effect. Any mature tree behind the first chopped tree will also be considered chopped and so on regardless if they have protesters on them not. This process stops when either the edge of the board or a space occupied by anything other than a mature tree is reached. Score 1 point for each tree removed in this way. Add any protesters from felled trees to your supply.
For example, a given row can have this formation: Player-Mature Tree-Mature Tree-Sapling-Mature Tree. When the player chops the first tree, the second one will be removed as well. However, the domino effect ends at the sapling because it is not fully mature. The sapling and the last mature tree remain on the board.
Logger is a game of equal turns. When a player reaches 10 points, the end game condition is reached. All players who have not had a turn this round will get one final turn. (Example: Player 2 reaches 10 points. Players 3 and 4 will receive one additional turn, but Player 1 does not. However, if Player 4 reaches 10 points, the game ends immediately.)
The player with the most points at the end of the game wins. In case of a tie, the player with more protesters in reserve wins.