As Forestry’s budget allows, we may enact a tree pruning program in limited neighborhoods where many of the city trees need pruning for street and sidewalk clearance and especially for promoting healthy structure.
Pruning can benefit a tree during any life stage, although it is especially important for a professional arborist to train young trees to develop a strong structure, as this makes them less prone to failure as they get older. Changes made now will significantly benefit the longevity and health of trees in the area.
Pruning on older trees focuses on removing deadwood and achieving clearance over streets and sidewalks. 8 ft of clearance over the sidewalk and 14ft of clearance over the street is required.
Pruning objectives
Clearance
Raise low branches on trees for street and sidewalk clearance, as well as a stop sign and corner/intersection visibility.
Structure (young trees)
- Remove or reduce large limbs that originate low on the trunk (low limbs that are left are more likely to interfere with street traffic, large trucks, etc.) By removing or reducing lower limbs on young trees, the tree has a chance to put more energy into its upright leaders. It is better to cut limbs before they get too large.
- Remove crossing/rubbing limbs. Many times, un-pruned trees will develop multiple branches that grow into each other, or that take up the same space. Leaving well-spaced scaffold branches ensures a stronger structure.
- Select a single upright leader (when possible). We may reduce (shorten) or remove competing/multiple upright shoots to allow one to dominate. In our streetscapes, some trees tend to develop multiple upright leads. However, during early or late snow events or windstorms, these branches are more likely to break or suffer from damage. By developing a good structure now, damage or failure potential can be reduced.
Health
- We may elect to remove a tree if its health or structure is significantly compromised; if it is planted in a poor location such that it will cause significant damage to infrastructure or hinder public safety; or if it is a non-approved street tree that is causing or is likely to cause significant issues in the future.
Please note:
Although the tree may look quite different immediately after pruning, city arborists have the long-term health of the trees in mind. Correcting defective branching structures now will allow the trees to put more energy into the preferred limbs. While it can be a shock to see significant corrective actions after many years of unchecked growth, within a few years, the trees will adapt, fill in, and become much stronger, healthier, and more valuable assets for our community.
Contrary to some pruning prescriptions for private trees in your yard that perfectly balances a tree, the city trees will be pruned with a different scope in mind; we will focus first on clearance and corrective pruning. Balancing or symmetry may not occur during the initial pruning cycle, as this may remove too many limbs at one time. Arborists will use discretion when deciding the number of limbs to remove.
Resources
A right of way (R.O.W.) is the city-owned area of land designated for streets, sidewalks, and public use. It includes the parkway between sidewalks and curbs. Where sidewalks are attached to curbs, the R.O.W. extends a distance into the property. The exact distance varies from street to street.
The abutting property owner is responsible for watering/fertilizing the trees in the R.O.W., and caring for and maintaining any shrubs or other vegetation. City Forestry is responsible for pruning, removal, and health management of trees in the R.O.W.
A City Forester’s Permit is required to plant, remove, prune, or spray trees in the street right-of-way (City Code 4.4.101-A).