Planting an Urban Forest: An Interview with Tree San Diego
When you think of city management and design, do trees come to mind?
The good folks at Tree San Diego think so, and think that you should too!
Tree San Diego is an urban forestry nonprofit who works to increase the quality and density of San Diego’s urban forest — and they have some thoughts about the importance of urban trees and how they contribute to a resilient community.
Trees, and by extension, the “urban canopy” (the layer of leaves, branches, and stems of trees that cover the ground in an urban environment when viewed from above), have an important role in city design. They make cities cooler, quieter, more desirable, more efficient, and safer — and therefore, more resilient. San Diego has recently announced a plan for a dramatic increase in our urban canopy in hopes of reaping some of these benefits — and I turned to the experts at Tree San Diego to find out more.
In this interview, you’ll learn all about why we need to have trees in our urban spaces, not just on our trails, as well as the number of benefits that urban trees and urban forests provide! You’ll also learn how Tree San Diego works to select their species, how they account for disease and pests, and the role of trees in urban planning.
If you’d like to learn more about Tree San Diego and their mission, you can check them out on their website. I’d also like to give a special thanks to Elekra Fike-Data, Chris Klier, Chuck Morgan, and Kurt Peacock from Tree San Diego for their help and expertise with this interview.
What does the concept of resilience mean to you and Tree San Diego? And how are urban trees part of a resilient community?
Resilience is the ability to recover from problems or conditions that are not ideal. We at Tree SD are choosing tough, low to moderate water-use tree species to better prepare for the warming, drier climate we will face in the coming years.
San Diego hopes to increase their urban canopy to 35% of the city by 2035. Can you talk about the benefits of having such a large, developed urban canopy, and what that would mean to the average resident?
Hitting the 35% cover target will improve the quality of life for everyone in San Diego! Some of the immediate benefits include lowering temperatures, reducing pollution and storm water runoff, blocking ultraviolet light more effectively. Residents will want to be outdoors more, more active in recreational activity and lowering heating and cooling bills, which burns less fossil fuels.
Many folks associate San Diego (and, more broadly, Southern California), with palm trees — which are actually a non-native species! Can you talk about your process of choosing which trees (and where) to plant?
Palms may be iconic, but they do not provide the ecological benefits that broadleaf or evergreen trees provide. They require annual maintenance which makes them more expensive to maintain than other trees.
We base our tree selections on the soil volume available and the utility situation, such as overhead wires, to prolong the useful life of trees. Microclimates can also affect what we select — we need to keep in mind dimensions like sun vs. shade, soil grade, and proximity of buildings and other fixed infrastructure to the site, ultimately striving to maximize the size of any tree in a given site. The bigger the tree can grow, the more benefits it provides!
San Diego is known for being an extremely biodiverse area, and there are a number of extremely unique environments in the county — from desert, to mountains, to ocean, just to name a few. Can you talk about the importance of wilding the urban environment? Have you received support from the outdoors community for your initiative?
Wilding and rewilding our urban environments are important since it improves health, provides areas for recreation and relaxation, improves biodiversity, and expands our wildlands and ecosystem restoration. Here in San Diego, we see examples of this in our local estuaries from Carlsbad, to Carmel Valley, and Imperial Beach. Balboa Park is another example, which has both wilderness areas and more formal, landscaped areas. The various cities within San Diego are focusing now on more “plantscaping,” and adding trees to our urban areas. In fact, in small open areas around the city, local officials are now looking to create pocket parks!
Water use is always a major concern for any SoCal resident. How does planting more trees affect a city’s water and usage?
Planting trees uses a lot of water, especially during the establishment period. However, I believe the benefits gained with planting more trees far outweigh the additional water needed. For example, a tree cover will save 11,000 tons of soil annually in a medium sized city. A tree-shaded, air conditioned home can improve its efficiency by 10% and saves up to 34% of annual costs. Trees planted in the right place for a home can reduce heating costs up to 25%. Trees are natural air conditioners, cooling the air through transpiration (how plants evaporate water). Trees improve real estate value by 1% of sale price. Trees reduce and mask noise with white noise. One acre of trees will provide enough oxygen each day for 18 people to breath, while, at the same time, absorbing pollutants and filtering particulates. Trees planted in parking lots can reduce the ambient temperature by 3% and car interior by 30%. 100 mature trees intercept 210,000 gallons of water per year, allowing cities to spend less money on storm water control and keeping water pollution out of our estuaries, rivers and ocean. The list of benefits goes on and on!
On the campus of UC San Diego, there are 27,000 trees. These trees sequester 7,560 tons of CO2 annually, and remove 6,210 pounds of pollutants from the air. A study conducted by the human-environment laboratory of the University of Illinois at Urbana Champaign concluded that a tree-filled community recorded a lower incidence of violence and vandalism than a community that was less forested. Additionally, trees can lower stress and help provide speedy health recovery. The benefits are monumental!
Meanwhile, the city of San Diego is working to be water independent by recycling water. By the end of 2035, nearly 50% of San Diego water will be provided by taking waste water and purifying it to high-quality drinking water, and will actually cleaner and safer than our present drinking water. You can learn more about this initiative here. So there are a lot of things at play!
You also run a project that diverts end-of-life urban trees away from the wood-chipper/landfill and towards other products. Can you talk more about the success of this program, and the difference between what happens to a tree in this program vs a normal urban tree?
The Treejuvenation project was a small pilot that really started when we realized how many exotic trees are grown in the temparate San Diego climate. Once these trees reach the end of their life, they can be collected for their viable wood. The urban forester now thinks about what trees should be planted on a longer scale — not just thinking of planting the tree for now, but thinking about the end of life, and planting trees that can eventually turn into desirable lumber. As another benefit, the tree care industry strives to ensure that urban trees grow as straight as possible which makes them ideal for harvesting for lumber as opposed to being cut up and dumped in the landfill or chopped into firewood!
What do you see as the future of the tree in urban planning and design? Have you seen an uptick in support from governments and planners in including more environmental elements such as trees in new developments?
Trees are only increasing in importance for urban planning as we move forward into a changing climate. Many new developments have trees and environmental elements as a focal point, rather than an afterthought. This is a trend that we expect to see throughout urban planning, especially with support and funding opportunities from government and other stakeholders.
How are you helping build resilience into Tree San Diego? What is a major obstacle that you have overcome?
Tree San Diego is building organizational resilience through diversifying funding sources, strengthening partnerships, and growing to meet growing needs. While not unique to our organization, limitations related to COVID-19 were a major challenge. Tree San Diego prides itself on connecting and working with the community, but during the height of the pandemic we were unable to work face-to-face with folks. Instead, we adapted our programs, conducting our training virtually and delivering trees to be planted at individuals’ homes rather than community planting events.
Can you talk about your biggest success so far as part of Tree San Diego? What helped you achieve it?
Tree San Diego was recently awarded a federal IRA Urban Forestry Grant to continue planting trees, training candidates through our Treejectory workforce development program, and building a regional urban forestry management plan. This $2 million grant award will allow us to bring the benefits of trees to thousands of people while empowering communities in priority populations zones to grow and care for a newly planted urban forest.
I know you partner with a number of groups around San Diego. Do you have plans to partner with urban forestry groups outside of San Diego?
Yes, we will work alongside the US Forest Service, CAL FIRE, and other NGOs in California to achieve our goals of building a greener future.
What is next for Tree San Diego?
Tree San Diego will embark on a path to expand our impact, influence, and statewide partnership. As our team plans to celebrate the organization’s 10th anniversary in 2024, we are currently building models to broaden our shared urban forest and plan for sustainable urban forestry management throughout the region.
What are the best ways for people to learn more about, or get involved with, Tree San Diego?
Get involved and stay in contact with our team by joining the TSD Leaflet Newsletter, signing up for Tree Steward training, becoming a Terrific Tree Member, and donating to the cause.
Want to learn more? Go more in depth here:
City of San Diego’s Forest Management Programs