The Field

by Nate Lowry, ASLA

Ever wonder what our urban streets and avenues would be without street trees or other urban forestry components? Have you ever pulled into that shopping center from yesteryear only to find not a tree, planting island, or bit of shade in sight? How did that wall-to-wall paved impervious area make you feel? Can cities and urban infrastructure even exist and provide an ample quality of life without urban forestry?

Urban forestry is essential to our built environment and population centers and is defined by Wikipedia as the “care and management of single trees and tree populations in urban settings for the purpose of improving the urban environment.”

Healthy streetscapes and efforts to employ urban forestry techniques have a number of positive effects cities could likely not live without. Street trees help curb the urban heat island effect and can be effective in carbon sequestering in urban areas where carbon footprints tend to peak. They also provide much needed shade that improves not only the pedestrian experience, but also keeps your car cooler on a 90 degree day and helps businesses reduce energy use through less air conditioning. Street trees often increase property values, aid in stormwater management, and as an added benefit, attract tourism, businesses, and economic investment.

Ignoring urban forestry techniques often is not an option anymore for cities, with 80% and growing of Americans living in urban areas. In fact, many municipalities have gone the way of enhancing urban forestry environments and boosting tree inventories rather than neglecting them over the last couple of decades. If you think about any sprawling farm field across America, there often is no shade or vertical scale in sight until you get to the actual homestead. Farmers and ranchers have planted impactful trees around their homes for hundreds of years, often flanking all sides for obvious advantages. Cities are like the homestead on the farm—a vibrant urban forestry program is vital to keeping life comfortable and viable within.

The photo at the start of this post is from a project MacKay Sposito designed in Wilsonville, Oregon called Boone’s Ferry Road. Street trees were incorporated right into the stormwater planters and are an integral part of the rain garden drainage approach. Specific tree and shrub species were selected to aid and foster stormwater infiltration and treatment. Street trees, along with other plantings, help soften the rigid hardscape curbing and slotted openings in addition to improving stormwater quality. They also provide spring and fall color in addition to shading and buffering storefronts from the busy thoroughfare.

Many municipalities throughout the country and beyond have set out on aggressive urban forestry strategies to improve quality of life and take advantage of other added benefits. Many cities are now exploring technology like GIS to increase awareness and protection of their tree canopies, utilizing these systems for not only identification and inventory but also for health assessments.

The City of Charlotte, North Carolina in 2017 set a lofty goal of increasing tree canopy in its parks and streets by 50% by 2050. This was not decided on by just Charlotte elected officials and higher-ups—more than 40 organizations and 3,000 Charlotte residents shared input about the plan and 50% was the decided upon goal.

Louisville, Kentucky, rated the fourth hottest urban area in the US, recently looked to urban forestry to help combat summer temperatures and improve quality of life. They found street/open space trees provide the most cost-effective long term solution to mitigating heat islands and providing much needed heat reductions. They developed hot-spot maps and looked to infill troubled impervious areas with more street trees. Quality of life and the environmental effects weren’t the only thing Louisville was after—they found that if they can increase their tree canopy coverage to 45%, the city would attain a savings of 67 million KW of energy or $5 million alone in utilities savings annually! The photo below shows several involved citizens who are part of the ‘Citizen Forester Volunteer Group,’ a group that was established as part of the emphasis on urban forestry in Louisville (some even donning Louisville loves trees shirts!). Louisville also has a training program offering ‘Citizen Forester’ courses 101 and 102, as any good urban forestry program has to involve key stakeholders (and maybe even some free labor).

In Melbourne, Australia, due to a warming climate and decade-long drought, city officials set out on an aggressive 20-year urban forestry strategy aiming to double tree canopies by 2040. Since adopting the plan in 2012, Melbourne has planted nearly 12,000 new trees and mapped the species and health assessment of 70,000 others. This data allowed them to start diversifying their tree stock with a goal of providing no more than 5% of any one tree species, no more than 10% of any genus, and no more than 20% of any one tree family. This diversification means Melbourne will enjoy a vibrant tree canopy for decades to come, and one that is not nearly as susceptible to infections and die-off of certain tree species or genuses. City officials also believe this effort will help cool the city’s urban summertime temperatures by 4 degrees Celsius or more than a whopping 10 degrees Fahrenheit! Melbourne even put together a full-on urban forest manual to solidify their serious approach to urban forestry and urban quality of life (see summary graphic below).

Urban forestry is vital in today’s society and is at the forefront of managing our built environments, with non-stop growth and significant climatic challenges present everyday. Quality of life directly relates to comfort and sustainability; continuing to bolster street and other public tree canopies aids greatly in the feel and perception of our built environments, amongst many other benefits. So the next time you park under that street tree or plop down a blanket under a park tree, realize there is much more to the story than just shade for your car or lemonade in August. Those trees help lower the heat island effect, provide vertical scale at the pedestrian level, provide for social spaces where none would exist, help with reducing wind and noise, generally increase property values, and lower a business’s cost of goods sold through lower everyday energy use. You don’t have to be in a forest to hug a tree!

Nate Lowry, ASLA, is a licensed landscape architect for MacKay Sposito Engineering in Federal Way, WA. He has over 16 years of experience predominantly in the Puget Sound area. He is also a City Councilmember and member of the Pierce County Regional Council planning body.