Most (or all) forestry machines have a tab on the right (the one with the picture of a chest) which allows to change the permissions of that particular machine. It has 3 modes:
Public: Default. All players may interact with the block.
Restricted: All players may interact with the block but pipes/tubes may not. This mode also prevents others from breaking the block.
Private: Only you may interact with the block. This mode also prevents others from breaking the block.