Tree trimming is commonly done to give the tree a nice aesthetic look. However, safety and health need to be factors in tree trimming as well. In order to trim a tree in an attractive fashion, there are certain molds that arborists tend to follow. Some of the unclude crown thinning, crown raising, and crown reduction.  The crown of the tree is the top portion of the tree. To perform crown thinning, you need to make sure that you are cutting mainly vertical branches. Cutting the lateral branches will result in undesirable appearance in the tree. Thinning needs to be performed in order to keep airflow going throughout the trees. This results in a healthy tree. When a tree is thinned at the crown, you must make sure that you are not performing a different type of cut, called “topping”. This involves cutting off all of the tips of all of the apex branches. This will greatly hurt the tree and make it difficult for the tree to grow new branches. No more than one-fourth of the crown of a tree should be removed at a time. 

 Crown raising is another type of aesthetic trimming which involves cutting the lower lateral branches of a tree. As you cut up the tree, however, you must make sure that two-thirds of the tree’s height is consumed by live branches. This is a useful type of trimming that can be used when a tree is blocking a sign or walkway.

 Crown reduction is a type of tree trimming that is rarely practiced. It involves removing a large portion of the foliage from the tree. Large, vertical branches attached to the stump are cut, while lateral branches still remain. This is different from crown thinning in that it doesn’t involve just thinning of the tree, it also makes the tree shorter.