Tree Pruning - Seasonal trimming for a healthy tree.

It is all about the strength of a young tree's structure. New trees should be pruned with long term health in mind. This means favoring overall strength at first and then going for an emphasis on form an appearance as the tree matures. In later years, these earlier concerns should be based on maintaining the soundness of structure. The location where one branch attaches to another is called the node. This is the point at which a proper pruning cut should be made. During the growth part of the year, buds form and eventually turn into twigs. They will grow, forming nodes. The branch area between one node and the next is called the internode.

There are several different types of pruning. Among the most common are the following.

Crown Thinning

You should try not to remove more than one fourth of the living crown of a tree at any one time. If it is absolutely necessary to do so, the job should be done over a period of several years. Thinning is done to allow light to more easily penetrate and air to more freely circulate into the crown of the tree. It is important to preserve and maintain the form of the tree and to always keep in mind the load on the branches and the overall structural strength.

Branches that meet forming strong wider angles should be kept. Where branches meet and form narrow angles, included bark often builds up; causing a weak joint that might split. These should be removed. Sometimes, removing lateral branches from one stem will enable the other to become the dominant one. You should also prune branches that rub against each other.

The danger in removing too many laterals is the possible creation of lion's tails. These are large bunches of foliage at the ends of bare branches. This can result in sun scalding and leads to overall weakness and breakage.

If a dominant branch is damaged, it will be necessary to pick the strongest one among the co-dominant branches and prune away all of its major competition. Thus, it may replace the main branch over time.

Crown Raising

Here, lower branches are removed to make an area free for clearance of vehicles, pedestrians and lines of sight. Local ordinances will most likely specify the height requirements. When engaging in this type of pruning, remember that the ratio of living crown to total height of the tree should be two to three. That means that an eighteen foot tree should retain twelve feet of living branches on the top.

In a tree's first few years, some branches can be kept on the lower portion to encourage proper growth and prevent things like vandalism and sun scald. Keep them trimmed to slow their growth and eventually you can remove them entirely.

Crown Reduction

Sometimes a tree will grow too large for the space it occupies. There are two solutions when this happens: removal and replacement with a tree that will not overgrow its allotted area, or a pruning technique known as crown reduction. This second alternative is called drop crotch pruning and should be used only as a last resort. This method involves a thinning of the living crown and can result in damage to the stems. This can lead to decay and eventual loss of the tree anyway. Still, it is preferred to "topping" which can place more stress on the tree. The crown reduction method also helps to retain the shape of the tree and allows more time to pass between its use and the next needed pruning.