Barriers of the Woodchuck to plants
Surround the garden with a five foot piece of chicken wire fencing that is rigged so that the vertical part is about 24 inches high. Bend the fencing into the shape of L. Position the fence around the garden with the short arm of the L standing up (24 inches) and the long arm (about 36 inches) resting at least 1 foot below ground level. Completely cover the long arm with soil. The vertical arm of fence will stop the woodchuck above ground, and if he decides to dig his way in, he'll run into the wire buried in soil. You can also electrify a chicken wire fence for effective protection or place a hot shot wire about four to six inches above the ground and three or four inches away from the chicken wire fencing.
Barriers on the plants preventing Woodchuck contact
Three foot high trunk guards made from PVC or flashing around standard or semi-dwarf fruit trees. This will keep the hog from climbing or chewing the trunk. This system may not work on dwarf trees because they are too short from the ground to the first limbs.
Other Options - It does help to keep a swath of grass mowed all the way around the garden. This short grass deprives the woodchuck of shelter for at least a few seconds on his way to the garden so he may be less likely to take the chance to make himself vulnerable to his predators such as cats, dogs, and hawks.
A properly rigged electrified wire down low can also do the job.
For all the components you need to build an electric fence go to our Yardener's Tool Shed;click here