Tension wire is used on deer fencing for several reasons. 

For areas with high winds, tension wire helps sturdy the fence and block flying debris. Fence tensioning protects the fence mesh from falling tree limbs - therefore, if gardeners have trees on properties, tension wire is a must-have accessory.

Ultimately, tension wire steadies the fence from post to post, eliminating sagging. If homeowners plan to install a deer fence with posts less than 15 feet apart from one another, tension wire will most likely be used. The monofilament wire can be used to strengthen the top of the fence and halt jumping attempts from deer and other wildlife.