Main Street trees FAQ

Why were trees on Main Street removed?

In spring 2023, City of Littleton foresters declared that 64 honey locust trees lining Main Street were in serious health decline due to an extreme case of thyronectria canker. Unfortunately, the trees were too seriously damaged for mitigation. Foresters determined they posed a risk of falling limbs and decided to remove them.

What is Thyronectria Canker?
Thyronectria canker is a common fungal disease that affects honey locust trees. The fungus presents itself as bumpy or visibly sunken areas (cankers) on limbs of the tree. Within the sunken areas there are small, disc shaped, fruiting bodies that might be yellow or reddish. These spots will age, decay, and turn black over time causing deformations in the trunk and compromising structural integrity of the tree.

What about plans to sculpt some of the tree trunks into works of art?

While city planners initially hoped to have some of the honey locust trunks carved into sculptures, foresters determined the idea was not feasible. New streetscape elements will be discussed as part of the Project Downtown planning process (see below).

Is this related to Emerald Ash Borer (EAB)?

No, the two issues are completely unrelated. Thyronectria canker is a fungal disease whereas EAB is an insect. Though EAB is incredibly devastating, the pest only targets ash trees.

Learn about the emerald ash borer in Littleton.  

Are the trees going to be replanted?

Replanting will not take place at this time, as city planners engage the public in Project Downtown, a comprehensive effort to enhance downtown for generations to come. While trees and greenery have emerged as a high priority for residents, future planting will require proper infrastructure to support trees, including irrigation, structured soil, and the selection of appropriate tree species that are properly spaced and resistant to blight and disease.

Learn about Project Downtown.

What is structured soil?

Structured soil is a commonly used method for promoting healthier urban tree canopies by utilizing a type of medium that allows for adequate growth areas for tree roots and ensures the appropriate moisture content. There are a variety of solutions to accomplish this, and these will be explored in the planning and design components of Project Downtown.

How did ALL the locusts on Main Street get infected?

The small fruiting bodies, mentioned above, produce spores that can spread to any susceptible neighboring trees by wind, animals, and touching branches. Unfortunately, the honey locusts on Main Street represented a monoculture that allowed disease to spread quickly.

How can you spot thyronectria canker before it’s too late?

The presence of thyronectria canker in a tree can be identified by certain signs. These include premature yellowing and wilting of foliage, as well as early leaf drop. Additionally, one may observe yellow, red, or brown lesions that may cause injuries to the bark with slightly sunken spots in the branches or trunk of the tree. The sunken spots eventually break open, which exposes healthy tissue and leads to the oozing of sap and release of moisture. The decayed wood and blackened bark left behind emits a foul odor

If you believe your honey locust could be infected, call a City of Littleton certified arborist to assess the tree. View a list of licensed arborists.

What do I do if I have a honey locust?

Prevention is key! Promote tree health and vigor by fertilizing and watering your honey locust. Recommended watering rule of thumb for trees in Colorado is 10 gallons of water per inch of tree diameter. Stop the spread of fungi by only pruning diseased branches in dormancy. Canker fungi can grow on dead wood and produce spores that can infect nearby susceptible trees. Do not store or transport diseased honey locust firewood. Any damage to the base of the tree can become an entry point for fungi, so be diligent to protect your tree. Finally, if you must remove your honey locust, replant trees that are resistant to the fungi but still provide the important benefits we need to live.

What if I have questions?

For questions related to the tree removal project, please contact Kelsey Stansfield, Grounds, Open Space and Natural Resources Manager at 303-795-3766 or

For questions related to City events, please contact Kelli Narde, Director of Communications at 303-795-3733 or

For questions related to the Project Downtown, please contact Adrienne Burton, Senior Project Manager at 303-795-3863 or