Shade Tree Analyses
In 2007, the Shade Tree Committee worked with the City of Geneva to
conduct an analysis of the street trees using the USDA Forest
Service's
i-Tree Streets. A random 6% sample of City blocksides was
inventoried, from which the software created estimates with an
acceptable error. Here are some of the more useful:
Population
It is estimated that the City of Geneva has about 3,800 street
trees.
Species
Almost half of the street trees are Norway maples. The pie
chart below shows the percentage of other species in the top 10.
Age
Age is estimated by tree diameter, and many species increase about
1” in diameter every three years. As the graph below
demonstrates, the oldest common species are the silver maples and
the red oaks. The average age of the street tree population is
about 50 years.
Condition
Half of the City's street trees were found to be in good condition,
and another 40% in fair condition. Three percent were estimated to
be dead or dying at the time, and most of those have been removed
since the analysis was carried out.
Environmental benefits
Using the best available science, we can estimate that Geneva's
street trees deliver about $475,000 per year in environmental
benefits. These benefits include
- energy savings
- carbon dioxide removal
- air quality effects
- storm water abatement
- property value
Benefit-cost ratio
Using the annual benefits and city expenditures, we estimate that
the City's street trees return about $9 to the community for every
$1 invested.
Committee Work
Helpful Information
Tree Care
Related Links