Trager MicroForest Project
Founders Square
Louisville, Kentucky
2023 - Present
This project is possible through the generous support of the Trager Family Foundation and these additional sponsors.

Support the Trager MicroForest Project
Contact
Mary Bentley Houk or donate online at: http://give.louisville.edu/TragerMicroForest

The Trager MicroForest at Founders Square is exploring how intensely-planted urban spaces can promote a healthier and more vibrant city.

Located at 501 W. Muhammad Ali Boulevard, in downtown Louisville, Founders Square offers a platform for scientific inquiry into the ability of novel planting and designs to measurably improve multiple aspects of human and environmental health. As part of the UofL Christina Lee Brown Envirome Institute’s New Vision of Health Campus, the Trager MicroForest is helping us to better understand the potential of nature in cities.

Early thermal drone images of Founders Square


Current research at the Trager MicroForest includes:

  • Continual examination of the square’s microclimate to better understand how it affects visitors' comfort and to explore ways to reduce temperatures in the immediate area.
  • Measuring the positive impact of intensely planted green spaces on human stress to investigate whether the intervention (greening) can reduce the physiological and psychological stress that leads to chronic diseases.
  • Ongoing studies of changes to the local biodiversity, soil health, microbiome, and carbon sequestration capacities to see if small urban green spaces can mimic some of the benefits of existing, large forest plant communities.
  • Observing changes in social activity and uses of the area related to the strategic integration of nature and urban design into and around the square.

Phase One Open

Guided by the Trager MicroForest Concept Plan, Phase One of the Trager MicroForest began in April 2024 and was completed in June 2025, with the space was reopened to the public on April 30, 2025. This phase introduced substantial improvements to the former Founders Square.

Construction fencing came down on April 30th

Phase One

The first phase of the Trager MicroForest began with a detailed planting plan design working with our researchers, arborists and Gresham Smith.

Tree planting plan for Phase One of the Trager MicroForest

In partnership with the UofL Department of Geography and Geosciences, we installed meteorological sensors throughout the site to collect baseline data on the previous park configuration and to support ongoing monitoring of environmental changes resulting from the new design and plantings.

Dr. Gunter and Sean Willis install meteorological sensors at Founders Square

The Envirome Institute conducted initial studies on human stress levels associated with earlier versions of Founders Square. We will continue this research as the Trager MicroForest matures into a densely planted urban green space.

Our partners at the UofL's Department of Biology performed a variety of baseline studies of the site to better understand the state of the biodiversity of the bird and invertebrate populations, and the biological health and carbon sequestration capacity of the soil.

Wayne Long of the Jefferson County Extension Service collecting soil samples in 2023

We collected samples of the microbiome of the park before any construction or planting began so that at some point, we can follow up with post sampling and determine if there are any significant changes to the microscopic life that surrounds us.

Microbiome swabs taken around Founders Square pre-construction

A major component of Phase One involved depaving significant portions of the square to reduce hardscape and expand areas available for planting.

Removal of excess concrete
Removal of internal brick walkway

A 178-foot semi-circular retaining wall was also constructed, and over 750 tons of amended topsoil were added to enrich the site and support the growth of a vibrant central forest.

Prefabricated sections of the wall were delivered as they were completed and then installed on site
Once the wall was complete, about 40 truckloads of new top soil was brought in

To understand the vegetative mass changes of Founders Square, we conducted terrestrial LiDAR scans of the park before construction in 2023 and after the initial construction and planting in 2024. LiDAR scans utilize millions of points of data to provide a three-dimensional model of the site. We will continue to scan the forest to evaluate changes over time.

Terrestrial LiDAR scan of Founders Square in 2024

A new zoned irrigation system was installed to help establish the forest once it was planted. Particular care was given to the existing trees beyond the depaving with air spading to loosen up the compacted soils without damaging the established root systems.

Zoned irrigation system installation
Air spading around the existing mature trees

We planted 113 new trees—comprising canopy, codominant, and understory species—on this ¾-acre site, which already hosts 24 mature trees along the perimeter. In addition, we introduced 242 shrubs and a diverse mix of grasses to enhance vegetative cover.

Beginning of the central forest tree planting in November 2024
Tree planting in February 2025

To improve accessibility and engagement, we added more than 220 feet of crushed limestone pathways, creating a circular trail that invites visitors to walk through and experience the forest.

Two new light systems were installed in Phase One to provide appropriate down-lighting in the central forest and minimize blind spots in the forest while trying to avoid affecting plant cycles and growth. We added ground lighting along the bottom edge of the new retaining wall to illuminate the pathway and to give the central forest a sense of floating, and maybe help elevate nature and the important role it plays in our urban center.

Cantenary down-lighting in the central forest with additional lighting over the pathway
Programmable ground lighting along the edge of the retaining wall

Trager MicroForest Concept Plan

The initial idea of the Trager MicroForest began with conversations around how to improve downtown Louisville with the Trager Family Foundation, the Envirome Institute, Louisville Metro and other stakeholders. How could a small, underutilized urban green space better serve the aspirations of a healthier future for our city?

Beginning in early 2023, a series of public workshops and collaborative design sessions with our design consultants at Gresham Smith led to the development of the Trager MicroForest Concept Plan. This vision continues to guide the project, including Gresham Smith’s design for Phase One.

Phase Two: Realizing the full potential of the Trager MicroForest

As we nurture the new plantings from Phase One and continue to monitor the impacts of the intervention, we are actively planning Phase Two, which focuses on increasing greenness, enhancing social connectivity and improving the site's interface with its urban surroundings.

This next phase will address edge conditions and incorporate additional plantings and seating to attract and accommodate more visitors. Proposed features include a micro-retail structure at the southwest corner to increase site activation and visibility, as well as new pedestrian amenities such as lighting, various seating options, and improved sidewalks. These updates aim to enhance accessibility, reduce crossing distances along the adjacent streets, and expand stormwater-mitigating vegetative areas.

If you are interested in supporting Phase Two of the Trager MicroForest, please contact Mary Bentley Houk (marybentley.houk@louisville.edu) at the UofL Envirome Institute.

Follow the Progress and Get Involved

We have installed two Chronolog stations in Founders Square, one at the southwest corner near Armory Place and Muhammad Ali Blvd, and a second at the northeast corner. These stations allow us to produce crowd-sourced timelapse documentation of the progress of the Trager MicroForest's progress. Help us document the forest over time by following the instructions on the stations and uploading your photo to the timeline.

Scroll down to explore more about the Trager MicroForest – see photos of our progress, check out upcoming events, and find ways to get involved. You'll also find our ongoing project updates and a growing list of supporters who make this work possible.

The Trager MicroForest is made possible by our growing list of supporters:

Trager Family Foundation  |  The Owsley Brown II Family Foundation  |  The McCance Foundation  |  James Graham Brown Foundation  |  Sociable Weaver Foundation  |  Norton Family Foundation  |  Whittenberg Construction  |  Baldwin Wealth Partners  |  Smith Family  |  Moss Family  |  Campbell Family  |  Mulloy Family.

Latest Trager MicroForest Project Related News & Notes