Urban forests provide critical environmental benefits, but the resilience of these socio-ecological systems to stresses like pest and disease outbreaks relies on tree health and diversity. Despite this, low species diversity continues to be a challenge in urban forest management. Using a participatory research approach in central Florida (United States), we selected and tested underutilized native tree species (Celtis laevigata Willd., Ilex vomitoria Aiton, Taxodium ascendens Brongn., Ulmus alata Michx., and Viburnum obovatum Walter) in two urban settings (streetscape and park) in four communities (total n = 200). Our collaborative process was organized into five steps, including a 2-year monitoring period to assess mortality and health through establishment. At the end of the trial, 156 trees survived with annual mortality rates differing by species and plot type. Taxodium ascendens had the highest annual mortality of the five species trialed. Overall, U. alata and V. obovatum showed the greatest potential in central Florida urban settings. Our tree selection process can guide others who want to create forward-thinking and diverse planting lists. Furthermore, this project demonstrates that co-production of knowledge involving members of local municipalities, practitioners, and researchers can be an effective strategy for selecting and testing underutilized tree species.

While many practitioners and scholars understand the risks associated with low urban tree diversity, they often lack the ability to rectify this challenge on their own. The complex system of tree production and procurement is shaped by market pressures, nursery and site constraints, local governance, and differing professional objectives among those who grow, specify, and plant trees. To understand constraints to and opportunities for increasing urban tree diversity, we conducted a series of focus groups comprised of nursery growers, landscape architects, and municipal tree managers. Our results highlight a significant list of considerations and constraints to diversity, with some issues shared among green industries and some specific to growers or purchasers. In light of our findings, we outline actionable strategies for increasing urban tree diversity.

As urban development increases in density, the space to grow urban trees becomes more constrained. In heavily developed areas, small stature trees can be planted to reduce both above- and below-ground conflicts with infrastructure elements. However, even these species can interfere with pavement when placed in extremely confining conditions. In this study, we build on past work to determine the minimum planting space widths of small stature urban trees. Species, stem diameter, and the height at which stem diameter measurements occurred were all strong predictors of trunk flare (i.e., the interface region between large structural roots and the trunk) diameter (adjusted R² of 0.843). Additionally, we modelled the relationship between planting space and the presence or absence of pavement conflicts using the predictions derived from this effort to project the potential cost savings in two United States cities. Study results provide a guideline to create sufficient space for urban trees and minimize infrastructure damage and associated cost savings.

This new 13-page article combines canopy coverage data from all of Florida's metropolitan and micropolitan areas with ecological models developed by the USDA Forest Service to calculate several key benefits of urban trees and an approximation of their monetary value. Benefits of urban trees include carbon sequestration/storage, air pollution filtration, and stormwater mitigation. Written by Drew C. McLean, Andrew K. Koeser, Deborah R. Hilbert, Shawn Landry, Amr Abd-Elrahman, Katie Britt, Mary Lusk, Michael G. Andreu, and Robert J. Northrop, and published by the UF/IFAS Environmental Horticulture Department.https://edis.ifas.ufl.edu/ep595

Background: Public engagement is needed to make sure urban forestry management efforts align with the values of the public being served. Noting this, we determined current and desired urban forest access of Florida (United States) residents using the criteria from the 3-30-300 rule (i.e., 3 trees visible from home, 30% canopy in neighborhood, and a green space within 300 meters of home). Methods: A survey of 1,716 Florida residents was conducted to assess canopy coverage and green space access. Respondents were then asked if this level of urban forest access was sufficient for their needs. We also asked their perceptions of the benefits and drawbacks of urban trees and whether they had any negative interactions with trees in the past. Results: We found that 37.3% of Florida residents met all three criteria of the 3-30-300 rule. Despite this, half the respondents would prefer more trees in their neighborhoods. When asked to name the top benefits provided by trees, the most common responses were shade, beauty, and attracting wildlife. The most common drawbacks to urban trees included risk to property, leaves/debris, and fears regarding storms and hurricanes. Conclusions: Florida residents largely value their urban forest and would like to see it maintained or enhanced. Improving access to greenspaces for recreation is the most pressing concern for urban forest managers in Florida looking to meet the requirements of the 3-30-300 rule. Results from this study can inform and test urban forest management at national and global scales.