La Crosse Downtown Tree Program

Challenge

As a designated Tree City USA since 1989, the City of La Crosse takes pride in caring for their leafy assets throughout this Wisconsin community.

The trees lining La Crosse’s downtown streets offer a multitude of benefits, such as stormwater management, erosion control, enhancing air quality, and even providing habitat for native wildlife. Additionally, these urban trees provide economic advantages by enhancing property values and retail sales, fostering conditions for economic prosperity, and ultimately reducing crime rates.

Unfortunately, due to standard sidewalk cut-outs, soil conditions, and limited space in downtown business districts, trees in these urban areas typically have a lifespan of only about seven years, and the trees lining La Crosse’s downtown streets were no exception. Noting the poor condition of the trees along Cass Street, Main Street, State Street, 5th Avenue, and 7th Avenue, the City needed to take proactive measures to evaluate their health and improve or replace them as necessary.

Solution

To assess current conditions and plan for the long-term survival of these valuable resources, La Crosse officials called on the planning and landscape architecture expertise of SEH, along with tree specialist Legacy Trees, to implement a tree-planting program for a 12-block area in their downtown area.

The program's primary objective was straightforward: preserve existing trees and introduce new species diversity, providing them with optimal environmental conditions to thrive.

The City secured funding through the American Rescue Plan Act (ARPA) to augment tree coverage in the downtown area, aiding deeper soil installation for root establishment and adding trees to areas that had remained treeless for two decades.  

In April 2023, the team conducted an extensive tree inventory and assessment of every City-owned tree along downtown streets within the study area, considering factors such as health, species diversity, and environmental suitability. Armed with this valuable data, the team devised a strategic plan to prioritize essential enhancements, including tree maintenance, spacing adjustments, pruning, and disease management, while identifying locations requiring tree replacements. The program also incorporated guidelines for the selection of appropriate tree species to ensure a resilient and sustainable urban canopy.  

The project used two approaches to increase soil volume within the downtown core. The first approach used soil cells: a gridded framework system that supports the pedestrian pavement and allows good quality and uncompacted planting soil in areas well beyond the typical tree pit opening. Better soil, improved drainage, and increased air exchange leads to healthier and larger trees. Soil cell technology was used with 50 trees in the downtown district.

The second approach replaced compacted soils within larger tree pits located adjacent to open space, minimizing impacts to existing pavement. Soil aeration tubes were incorporated into the tree pit to increase gas exchange within the soil to encourage tree roots to establish throughout the soil volume, rather than staying within the top 9-18", a standard for urban trees. Eight trees were replaced using this technique, and new trees will be planted in the spring of 2024.

With an established program detailing ongoing care and maintenance in place, the residents of La Crosse are well-positioned to enjoy the environmental, social, and economic benefits of these beautiful, green resources for years to come.