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Tree Cages and Shelters

Bruce Pankratz

NW Wisconsin

(1000 words or so)

(uneaten tree growing through the top of a tree shelter)

Somewhere along the line you have probably heard someone say "the best time to plant a tree is twenty years ago". You might think that means trees take a while to grow tall. Sometimes this is true but where we live it means 19 years ago you had to replant the tree because a deer ate the first one so 18 years ago you could plant a third tree to replace the second one a deer ate and on and on. Twenty years later you may have given up on the idea of ever growing that tree long ago unless you found a tree deer do not like to eat. That is where tree shelters and cages come in. Instead of building a fence around your entire woodlot you either put a small fence cage or plastic tube around each tree. Tree shelters work only on trees with leaves and not needles but cages work with either. You will usually need to buy the plastic tubes called tree shelters. You can make tree cages yourself with fencing.

Tree cages or tree shelters are meant to keep deer from eating the top of the tree. There have been oak trees on our land perhaps ten years old but only about three feet tall covered with nipped-off and dead branches. After pruning the trees and putting them in a tree shelter the trees took off since there was already a good root system in the ground. Some are now twenty five feet tall or more. And without tree shelters or cages we would not be eating apples from the crop this year.

(tree shelters protecting oak trees)

Tree cages and shelters differ in price with the tree shelters I have used being more expensive. Unlike the shelters deer can eat the branches as they grow through the sides of the cages but deer usually have left the top of the skyward-growing top of the tree alone for both shelters and cages. Once the top of the tree grows beyond the top of the shelter or cage you can set the tree free by removing the cage or shelter. You can then reuse the cage or tree shelter. After liberating the tree you can prune the bottom branches (don't take too many at first) and a few year later all of the messy bottom of the tree has disappeared as the tree grows wider. Losing the branches at the bottom of the tree is better than no tree at all.

(three foot shelter with oak stake)

Let's take a closer look at commercially available tree shelters first. A commercial tree shelters look like a piece of plastic stove pipe so they are easier to see than cages. The the wind pushes on the entire shelter so they must be anchored more firmly than cages. Shelters are sold with 1" oak stakes. Shelters create a warmer and moister climate so the tree inside can grow faster than in a tree cage. Irrigating the tree means pouring water down into the tube.

To install a shelter simply push it over the tree. With nibbled trees you may need to prune enough of the tree off so the shelter fits. Next, slip the stake through the plastic fastening strips on the tube that will hold the tube to the stake, pound in the stake and then pull the fasteners tight. Leave the tubes touching the ground in the summer, raise the shelters up in the fall to let the tree harden up for winter and and then lower the shelters down again to keep the mice out. Keeping mice out is something the tree cages cages cannot do.

Shelters come in different heights. The smaller the shelter the easier for a deer to nibble off the top of the tree and stunt its growth. For us the best height has proved to be 5 feet. We tried some three foot shelters but many were knocked over or gnawed by bears back in the woods. We were able to reuse them a few years ago to protect small oak with better results but still think five feet is the minimum to be safe. Once the growing tree spread its branches too much after it successfully grows above the shelter, you cannot pull the shelter off and reuse it but if left on the tree, the shelters eventually decompose.

(five foot tree cage with 3 foot lath stakes)

Tree cages in contrast last a good long time and probably will have the bark grow around them if not removed in time. You can take the cages apart to get them off of trees if needed.

The best luck we've had with the tree cages we built ourselves was to start with a five foot roll of fencing costing about $41. We get about seventeen or eighteen cages from the 50 foot roll of fencing. For a cage with a diameter of about eleven inches cut a five foot by about 33" piece. The diameter of the shelter is roughly one third (Pi to be exact from geometry) of the circumference of the cage. When you cut the fence be sure to leave wire for attaching the cage together after you roll the fence piece into a cylinder. Once you have the cage built all you need do is put it around a tree and pound some stakes to keep it steady. Three foot wood lath (costs about ten cents each) works to hold the cage. Thread the lath through the cage from the outside at the bottom, pound it in and then weave the top of the lath back through the fence. There is not as much wind pressure on fencing compared to tree shelters and also the tree itself helps hold the fence when the branches grow out.

For people who have only a small number of trees to protect, cages or shelter may make sense but if you are trying to grow thousands of trees for income the idea of shelters may not. In any event you may only know if you made the right decision twenty years from now.