Gaylan Williams connected with urban forestry at exactly the right time.
Williams, an arborist and research associate who will be joining the Department of Planning and Landscape Architecture as an assistant professor this fall, had returned to his native New Orleans a few years earlier, where the ongoing recovery from Hurricane Katrina offered plenty of opportunities for the landscape design skills he had learned as an undergraduate at Louisiana State University. Williams applied the concepts of green-blue infrastructure — landscape design that includes a strategic mixture of water and planting materials — to the city’s age-old problems: heavy rainfall, difficult drainage situations and aged infrastructure.
“The biggest part of it was managing stormwater as close to where it falls as possible, not centralizing it or bring it across town to a large detention basin, but incrementally manage the runoff in predetermined locations within our urban landscape, because that’s kind of how rain happens, dispersed pockets of precipitation across the city,” Williams says. “With more severe storms on the horizon due to climate change, we must design mechanisms that keep additional pressure off our aging municipal drainage systems in order to reduce the frequency of flooding.”
Williams used sustainability metrics to gain an understanding of how much water runoff could be decreased by specific design interventions, like bioswales and detention ponds, solutions that can also improve water quality. But Williams also knew this was only part of the solution for the built environment in New Orleans. He found the other part in trees — or, more specifically, in urban forestry, the care and management of tree populations to improve urban environments.
“My research revolves around understanding the metrics of what trees bring to the environment and using that understanding as a better way to design urban and rural landscapes,” explains Williams, who earned his doctorate in urban forestry from Southern University in 2022. “So not only are we designing our landscapes, using plants, based on aesthetics but also based on performance.”
The timing has been fortuitous. The Inflation Reduction Act of 2022 pumped billions of dollars into underserved communities across the United States to help them plant trees. Williams and other urban foresters have mobilized to educate these communities about which types of trees they should be planting to achieve the greatest environmental benefits.
“In some cases, cities do not understand what each tree is specifically doing for their urban environment,” explains Williams. “Cities are just planting as many trees as they can, given the species available at the local nurseries and farms. However, the literature tells us that while this approach does work in certain aspects, it neglects important equity and environmental justice considerations.”
Williams ticks off the critical questions that aren’t always asked when tree-planting efforts are implemented: Does the community want the trees? If so, why? How do they want the plantings to look? How do they want the plantings to perform? What are the right trees for this area? In Williams’ view, many urban forest management plans lack a comprehensive approach.
Williams studied the problem himself during his dissertation work. He examined an urban park in New Orleans and determined that, given the biodiversity landscape of the area, red maples were the best choice to address carbon sequestration. Another tree, the lacebark elm, outperformed the red maple, but the tree is considered invasive, making it a poor choice for the park environment.
“Everyone wants this overarching rule of thumb when it comes to planting trees and it’s not that simple,” he says. “You have to first identify where you’re planting the trees and then determine why. In this community, what tree species would improve the quality of life of residents and visitors?”
One of the issues urban planners and landscape architects like Williams often need to overcome is what he calls a community’s fear of trees — homeowners concerned about new tree plantings creating problems for their sidewalks, roofs, and driveways or concerns about potential impacts to property value. The solution, he says, could be in changing the ways in which they are planted.
“Right now, we have these huge trees planted over 50 years ago that are falling every time there’s a big storm,” he says. “But if we look at how trees grow in nature, more closely together, forming these dense buffers and barriers, maybe we could incorporate this aesthetic, designing windbreaks, to help our trees survive as climates and weather patterns become more severe.”
Finding the proper scale of how communities can implement urban forestry principles to get the most holistic and cost-effective results and doing community outreach on how best to do it will be critical, says Williams. He points again to New Orleans, where, 20 years ago, people balked at the idea of using retention basins to manage water over concerns about mosquitoes and the diseases they often carry. Today, small basins are a key part of urban runoff management.
“It took 15 years of dedicated community education to get New Orleanians to embrace stormwater management, and I think the same commitment is required for urban trees,” says Williams. “How do we bring the research and science from academia to practice in a way that is scaled and curated correctly for each region, so that practitioners can incorporate these insights into their designs?”