Stakes
A line of stakes is designed to discourage cavalry charges due to the high casualties caused, and generally slow other units down as they traverse them. Stakes are laid along the front of the unit laying them, in the direction that unit is facing, and are just as dangerous to friendly units as enemies - so much care and consideration is required. During the battle, stakes gradually become uprooted and ineffective, and once a unit has laid a line they can lay another, but the first line will be removed.