Tree Pruning and Maintenance

In urban landscapes, tree pruning is needed to improve overall structure, to enhance vitality and to maintain safety and aesthetics.  To optimize the tree health and structure through pruning, there must be a basic knowledge of tree biology.  Pruning cuts must be made with an understanding of how the tree will respond.  Take it from The BIG Oak, improper pruning is harmful and can cause damage that will remain with a tree for the remainder of its life.

Reasons for Tree Pruning

  • To improve overall structure and branching patterns (structural prune)

  • Reduce chance of limb failure (structural prune)

  • To remove or reduce hazardous limbs (safety)

  • To provide clearance from buildings, structures, wires or other trees (practical)

  • To remove lower limbs (crown raising)

  • To remove dead or dying limbs (crown cleaning)

  • To remove diseased limbs (health)

  • To improve a view (vista pruning)

  • To increase flowering / fruiting

Pruning Considerations

Many considerations must be made before pruning any tree.  The type of pruning will be much different for younger developing trees when compared to older, mature trees. 

Here are a few considerations:

  • Tree species

  • Age of tree

  • Current health of tree

  • Structural issues

  • Safety concerns / hazardous conditions

  • Tree location / site conditions

  • Purpose of pruning

Pruning During the Dormant Season

The best time to prune a tree will vary based upon tree species, tree health and pruning objectives.  As a general rule, the dormant season is the best time of the year for most tree pruning. Here are some reasons why:

  1. Minimizes the risk of insect pest issues

  2. Minimized threat of spreading diseases such as oak wilt, cankers or fire blight

  3. Results in the least impact on the tree health since stored energy is at its highest point

  4. Easier to visually inspect the entire crown of the tree for structural concerns with no leaves

  5. Less impact on surrounding plants and landscape

Pruning for Mature Trees

When pruning mature trees, priority must be given to make sure trees are safe since larger trees have a higher chance of causing damage.  For larger trees, tree pruning should be kept to maintaining the existing structure (not changing the structure).  If the tree has a well-established structure, the majority of pruning needed should only be for deadwood removal and crown raising or clearance from structures.  The BIG Oak must insist that the removal of live limbs on mature trees should be kept to a minimum.  Removing a large portion of live tissue on a mature tree can have negative impact to both tree health and structure.   Pruning objectives for older trees should be:

  • Reduce the risk of failure

  • Minimize the removal of live tissue

  • Allow for ground and structure clearance

  • Maintain structure and health (do not change it drastically)

Pruning for Younger Trees

The pruning of younger trees is important to help develop proper structure and branching patterns.  Young trees that have been pruned have a lower potential for limb failure and will require less maintenance in future years.  A larger percentage of live limbs can be pruned for younger trees (up to 25-30% at one pruning visit), so this is important structural cuts need to be made. This is completely the opposite for pruning older trees.

  • Training will develop trees that are structurally sound minimizing the negative effects of co-dominant stems, weakly attached limbs and redundant limbs.

  • Fewer failures, potential hazards and defects in trees will make for a sustainable urban forest. 

  • Well-spaced limbs will equate to fewer limbs to be pruned in the future.

  • Well-developed tree crowns will result in trees that are more aesthetically pleasing and safer.

Proper Pruning Cuts

Pruning cuts must be made so the tree has the best opportunity to seal off and compartmentalize the wound.  Every pruning cut has an impact on the tree. The BIG Oak says “no pruning cut is better than a bad pruning cut”. Remember, trees DO NOT heal, they only seal off the wound.

Pruning tip from The BIG Oak =

Starting a tree pruning program when trees are young can be one of the most important elements of long-term planning. Pruning young trees is often inexpensive (per tree), but if often overlooked. Developing trees with solid overall structure will save money and will save trees.