Standard trees hardly need any explanation. These are the varieties that are most common, and probably what you picture when you think of any tree. No specific shaping is required to get the shape to take this form. Just let it go and prune it as you would normally, and unless you have a strangely deformed tree then it should end up being a standard tree.
It is possible to turn a standard tree into a bush tree through pruning. The branches take the same shape, but the stem or trunk of the tree is noticeably shorter. This can be beneficial if you want to grow trees, but don’t want to block the view. For example, my house has a great view of the Rocky Mountains. I didn’t want to sacrifice this gorgeous view, so I grew my trees up as bush trees.
Cordons are a type of tree that you might not be familiar with. It consists of one stem with no branches. It is planted at an angle so that it arches up over the ground. Through the course of its growth, all branches are removed. These are beneficial because they take up very small amounts of space and more can be fit in a certain square footage. The only negative aspect is that they produce smaller amounts of fruit per tree.
Espalier trees grow with a single vertical stem in the center, and several horizontal branches on each side. These allow for long rows of trees, while still producing large amounts of fruit. If you operate an orchard, you probably use this shape to fit as many trees as possible into the area you have.
Fan trees use the same theory as espalier trees. However, the shape is slightly different. The same central vertical stem is used, but the connected branches are not horizontal; they grow in the same pattern as a standard tree, only they are two dimensional rather than three dimensional. They are also used to save space, and are used instead of espalier trees for certain types of trees that do better with sloped branches.
Another type of espalier is the step-over espalier. They are like a normal espalier, but with just one horizontal branch very close to the ground. They are particularly interesting because they still produce delicious fruit while providing a border for whatever you want. I have used step-over trees to fence of my garden. They are definitely my favorite shape of tree, mainly because they are like a fence that bears fruit. What’s not to love?
As you can see, each of these shapes has its own benefits and negative aspects as well. If any of these sounds like they would be a good fit for your garden, you can ask your local nursery employees or favorite tree service company in Pittsburgh PA for advice on reading material that will help you achieve your goals. Most of the time, getting the tree into the desired shape is a very easy process and just requires some guidance at the beginning.