Delaware Public Media

Enlighten Me: Bringing the elm back to American cities

Feb 7, 2020

The virulent strain of Dutch Elm Disease caused the death of most of America’s elm trees.

But some elms have proven to be resistant, and the U.S. Forest Service has been breeding these survivor elms for planting.

In this week’s Enlighten Me, Delaware Public Media’s Nick Ciolino talks with Universiy of Delaware Professor of Urban Forestry Tara Trammell about a project to plant these elms in urban areas to replace an aging canopy in places that can be harsh for young trees like Newark, Delaware.


“It’s important to plant them, because they can help mitigate storm water and runoff and flooding. They’re important for cooling the environment as well,” said Trammell. “So putting trees in these locations they don’t already have trees, that can actually benefit from having them is an important task.”     

The project planted 45 trees in Newark using three elm varieties at 15 locations of varying harshness. 

Trammell says researchers will study how fast the trees are growing and study the leaves for indications of stress in a hope to assess which aspects of the urban environment limit tree growth.

“Urban conditions can be quite stressful, with soil compaction, water availability, nutrient deficiencies or heat stress,” she said. “If we look at some of these compounds or internal structures, we might be able to see what types of stresses these trees are experiencing.”     

Trees were also planted in Philadelphia and Columbus, Ohio.