Martha Isler, chairperson of the Pittsburgh Shade Tree Commission, has seen it all.
Forgotten trees. Unwanted trees. Trees damaged by ill-advised pruning schedules. Trees poisoned by street salt. Someone once cut down a single tree to steal the bicycle it was chained to.
You can't just plant them and forget them, she said.
"Maintaining the health of those trees, that’s very important to us,” she said.
The commission tracks about 33,000 street trees in the city of Pittsburgh. Nearly half were planted in the last several years, she said. At the group's urging, city officials issued a request for proposals to study what other cities have done to protect their tree canopy and put some of those suggestions into the city code.
Construction projects and careless contractors routinely threaten the health of the city treescape, according to Isler.
“The impact on street trees sometimes is harmful or deadly, and what we need to do is to revise our [city code] language so it’s clear that contractors are responsible for any trees that are in the right of way and if they damage them, they are responsible for the cost of replacement," she said.
Protecting and planting a variety of trees is important to increasing the city’s street tree canopy -- the land area covered by tree crowns when viewed from the air -- which currently stands at 43 percent. The commission aims to reach 60 percent over the next 20 years.
“It’s important for storm water runoff, for air quality, for shading in the summer, for protection of wildlife," she said.
The Shade Tree Commission hopes to make suggestions to the mayor’s office and city council by next spring. Implementation could begin as early as next summer.
But individuals are just as dangerous, Isler said.
“People who want to protect a view will chop a tree. We have people who want to prune and prune at the wrong time of the year. For example, you can never prune an oak tree till the tree stops absorbing food through their system, because there is a disease called oak wilt,” which Isler said can easily spread to other nearby oaks through the root system.
Residents can prune a tree on a city right of way adjacent to their property, according to Isler, but you have to get a permit from the Forestry Division of the city’s Department of Public Works.
Protecting drivers during winter months can also damage trees and threaten family pets because of the high salt content of some de-icing materials dumped on city streets.
“It’s killed a lot of trees in our city," she said. "One of the standards we’re looking at is requiring low magnesium de-icing products so that we can better protect the trees we have during those winter months.”
