Planning and Design

Hazards

There are many hazards associated with trees, such as those produced when trees fall during storms or die and begin to fall. However, falling trees are not the only potential for problems.

Urban trees should never be allowed to grow in designated clear zones for utility lines, pedestrian walkways, buildings, streets and travel lanes. When trees are allowed to grow un-checked into these areas they reduce clearance and sight distance and increase costs to maintain public safety. Additionally, if the upper portions of the tree are left to tower over property it can cause power outages, damage to homes, vehicles and other property. There is also an increased risk for personal injury.

An often overlooked liability is the root structure of the tree. Tree roots that surface above ground can pose a tripping hazard or damage equipment such as lawn mower blades.

In many cities, communities are finding themselves spending millions of dollars to resolve conflicts caused when trees impose on sidewalks, sewers, power lines and other elements of urban infrastructure. Studies have shown that repair costs for sidewalk, curb and gutter repair, tree removal and replacement and legal and liability costs range from $0.75 to $2.36 per capita and up to $6.98 per resident. When figuring in the additional costs of repairing damaged sewer lines, pavement, building foundations and other damaged materials, total costs add up to as much as $100 million per year in larger cities.

Unfortunately, when these repairs become necessary municipalities are sometimes forced to shift these costs to residents. Typically, this leads to a downsizing in urban forests as small stature trees are planted to replace the larger trees removed due to their damaging effects.

Trees
Site Preparation
Management
Hazards
Cost/Benefit Analysis
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