Downtown Canopy

Downtown Dover's Canopy

The street trees that make up downtown Dover's urban canopy play a vital role in the city’s environment. The Central Business District (CBD) Street Tree Plan and the Master Plan’s Climate Adaptation Chapter outline goals for enhancing this canopy, including improving stormwater management, filtering air pollutants, and lowering surface and air temperatures.

Street trees planted today typically have tap roots and deeper and more vertical roots as they have been found to promote greater infiltration than species with fibrous roots and more lateral, shallower roots. Deeper roots can help preserve sidewalks longer than trees with roots that tend to spread horizontally.

Careful consideration is put into the recommended species selections due to the environment that street trees inhabit which can involve poor drainage, limited sunlight, concentration of car exhaust and animal waste, and the presence of public infrastructure that can incur damage from tree roots and branches as well as interfere with tree growth. 

Today’s street tree selections are intended to thrive in Dover’s downtown and help build a greener, more resilient urban environment for years to come.

Threats to the Downtown Canopy

As mentioned above, street trees face particularly challenging conditions in an urban environment. These conditions include poor drainage, limited sunlight, a concentration of car exhaust and animal waste, and the presence of public infrastructure that can be damaged by street trees and impact their growth. 

Currently, Dover's downtown canopy is primarily made up of ash trees. Ash trees across the country, including throughout Dover, have been impacted by the emerald ash borer, a highly destructive invasive insect that has devastated ash tree populations across the country.

Emerald Ash Borer

Many ash trees in Dover’s downtown are in visible decline due to infestation by the emerald ash borer (EAB), an invasive insect that has spread across New Hampshire since 2013. EAB larvae feed beneath the bark, disrupting water and nutrient flow, with early signs including canopy dieback, bark splitting, woodpecker damage, and small D‑shaped exit holes.

Once symptoms appear, damage is typically irreversible, and dying ash trees become brittle, posing serious safety risks in busy areas. Because of the hazards and specialized equipment required for removal, the Community Services Department has been pruning affected trees for now, but most will need to be removed within one to two years. 

Replacing the affected ash trees will have a dramatic impact on the look and feel of the downtown area but it will allow for safe conditions and the opportunity to replant with a more diverse, resilient urban forest.

As the city plans for this project, you can give feedback on how you would like the downtown landscape to look by clicking here. 

More information on the EAB can be found here.

Resources:

Central Business District (CBD) Street Tree Plan 

The CBD Street Tree Plan, funded by the NH Department of Environmental Services Coastal Program, aimed to enhance Dover’s climate resilience by improving the urban landscape and promoting innovative stormwater design education.

The Street Tree Plan can be found here. 

The Street Tree Plan Fact Sheet can be found here. 

Master Plan, Climate Adaptation Chapter

In 2018, the City of Dover adopted the Climate Adaptation Chapter of the Master Plan. The development of the chapter was led by a citizen steering committee with support from regional and university partners. 

The Climate Adaptation Chapter can be found here.