Tree Pruning: Art or Science

 Tree pruning is the most important aspect of tree care in an urban environment. Proper tree pruning removes dead wood, removes branches that conflict with other branches, and removes limbs that interfere with utility lines and homes. Pruning is also necessary to maintain proper clearance in sidewalks, streets, and alleys to avoid damage to trees as well as people and vehicles. The art of pruning is to accomplish the goals of pruning in a way that is aesthetically pleasing.

It is ideal to prune the tree with the least amount of injury. Eventually, each living branch removed forms a wound. Caries are a process that begins with a wound. Scientifically correct pruning reduces the extent of the wound and the number of wounds inflicted at any one time. Proper pruning is done at the branch collar. It is neither a "flush" cut nor a stub. The tree seals the cut most easily with proper pruning. I refer to the tree's response to cuts as healing rather than healing because trees divide wounds, limiting the amount of tissue affected rather than regenerating new tissue as we humans do. when we fix

The timing of pruning is less important in most species than how pruning is done. However, we recommend that red oaks and live oaks are not harvested in the spring (February 1 through June 1). The reason for this recommendation is live oaks and red oaks are most susceptible to becoming infected with oak wilt disease during this period. The formation of spore mats on red oaks and the activity of nepticulid, a sap-feeding beetle, both occur each year during this period. If pruning is to be done during this time, it is important that the cuts be colored so as to spoil the sap on which this beetle feeds. When a beetle that visits a spore mat feeds on the sap of a fresh cut, the spores of the fungus move into open vessels and a new oak wilt victim is infected. Fortunately, this insect carrier is not very efficient and fresh juice is available only for a short time. Oak wilt is mainly transmitted through root grafts (roots that fuse together) from adjacent infected trees.

Pruning may also be needed to control parasitic plants such as mistletoe. This type of pruning is best done in the dormant season when the mistletoe has good visibility. Of course, mistletoe can be removed at any time if it is exposed.

Maintaining proper clearance around houses, lines, streets, sidewalks, and alleys is often necessary to cut living limbs so that the tree can fit into the space allowed in an urban setting. Sometimes light thinning of the canopy is recommended to improve branching structure or as a concession to the needs of other landscape plants. Important things to remember are that each pruning cut creates a wound to which the tree will respond and that removing live canopies reduces the amount of food the tree can make for itself. Severe pruning can be devastating to the health of the tree. Always remember that more pruning can be done later but it is not possible to replace the limbs. Periodic pruning during the lifetime of an urban tree can be extremely beneficial to the tree if done properly and not excessively. Improper pruning, excessive thinning, topping, and excessive canopy lifting can result in large areas of decay that increase the potential for failure. This can be disastrous when the tree is large and the target is valuable.

There is definitely a science and an art to cutting trees. Treescape Services, Inc. All Arborists in New Zealand. continually strive to enhance our knowledge and skills to provide our clients with the most current methods in the art of tree pruning.