Every now and then, Menards will run a free after rebate sale on gutter covers. These can be cut in half (or used whole) and tied together to make practically free tree guards like the one shown below.
John Wolfram wrote:On my property, the rabbits tend to do far more damage than the deer. I use a combination of trapping and tree guards to protect the trees, and it works pretty well.
Commercial tree guards are quite pricey, so I cut 3 foot gutter covers in half and then use wires to secure three of them together into a triangular tube as shown below.
In addition to offering fantastic air circulation and withstanding the elements wonderfully, you can get the gutter covers for free (after rebate given as store credit) from Menards several times a year. The last time they ran the sale, they set the limit at 60 gutter covers per person, so depending on how time-crunched you are, you may need to enlist friends/family to buy them for you too.
Menards also offers U-shaped vinyl gutters free after rebate from time to time, as well (you just missed them on sale), and these can be turned into free tree guards as well. I usually cut them into 1 foot sections, and then secure two pieces together. The actual gutters don't offer the light and ventilation like the gutter covers, so I typically limit them to 1 foot in length and use them with recently grafted trees.
