Pruning & Trimming


It needs to be emphasized that proper cutting technique is extremely important. Improper cuts do not heal well resulting in decay that can spread. Dead-wooding is important: dead branches should be removed as they are harmful for the tree's health. Poor pruning can take years to correct, and in some situations, the damage is irreversible. Unfortunately, many people are still engaging in faulty pruning practices that have been proven to be harmful. Research in arboriculture is ongoing throughout the world, and all tree care practices should be based on solid scientific research, not "this is the way my dad taught me." Frequently, one will see a truck in the neighborhood that lists all of the services that they provide: yard cleanup, grass cutting, pressure washing, landscaping, and tree pruning. It is unlikely such a person is a trained professional in the trimming and care of trees. Pruning is not a skill learned overnight, and one should entrust the care of their trees to knowledgeable and experienced professionals.

An interested homeowner can learn many pruning skills, and of course, pruning and caring for your trees is a wonderful hobby. But again, sometimes it is better to work alongside a reputable tree service company. Large trees and hazardous situations are best left to the professional. Too many homeowners are seriously injured while working in tall trees or hedge-trimming off of high ladders. Leaning from a ladder with a chainsaw invites disaster. Working near power lines is extremely dangerous, and again, should only be done by professionals.

For more information on proper pruning techniques, there are excellent books and informative web-sites. A few important details for homeowners are included below:

  • Look for any major cavity rot in the trunk and large branches.
  • Look for hanging branches and have them removed immediately. They are called "widow-makers" for a reason and may fall at any time.
  • Diseased and decaying wood can be removed at any time of the year.
  • Prune at the branch collar to promote healing of the wound.
  • Remove criss-cross or rubbing branches. The bark is often damaged and becomes an entry point for disease.
  • Prune at the right time: some trees should only be pruned at certain times of the year.
  • Remove diseased or insect-infested branches.
  • Avoid tipping and topping cuts, and never leave stubs. Use thinning cuts.
  • Remove watersprouts and suckers in deciduous trees.
  • Do not prune more than 1/3 of the canopy.
  • Remove branches that interfere with visibility: traffic, crosswalks, traffic lights, street lights etc.
  • Raise the canopy (remove branches) if the branches block ground floor windows and doors.
  • Break-ins are discouraged when there is greater visibility. Low branches that interfere with trucks or vans should also be removed.

Topping should not be done as it is usually very harmful for the tree and may dramatically increase the tree's hazard rating. Weakly attached leaders grow in size and often fall in the wind 10 or 20 years after the topping. Previously topped trees are often dangerous and should be inspected by a qualified arborist who can recommend possible solutions: removal, cabling/bracing, re-topping or ongoing inspection. A much better alternative for large trees is spiral thinning (canopy thinning) which decreases wind resistance. Such trimming allows the wind to pass through the trees, decreasing the likelihood that the tree will fall due to wind-throw. It also allows more light penetration and air circulation, both important for the tree's health. (See the ISA website for further information about topping.)