While we all admire the beauty of a tall sugar maple turning hues of crimson and orange in the fall, the cooling shade of a sycamore in the summertime, and the year-round greenery of a pine or spruce, some may take for granted, or not be aware, of the planning and effort required to integrate trees into the urban environment. As air and water pollution, climate change, flooding, and heat islands in major cities threaten our health and well-being, efforts are increasing around the world to not only increase the tree canopy, but to protect trees already in the ground.
In Philadelphia, the Pennsylvania Horticultural Society has trained, supported, and partnered with more than 5,000 volunteer Tree Tenders to plant 17,000 trees over the last decade. PHS continues to be at the forefront of the urban tree movement across the country, contributing to the increasing body of science and research that seeks to understand the benefits of urban canopy coverage, and to document the history of tree-planting efforts in cities throughout the US and beyond.
“Today, street trees play a big role in discussions about the urban and global climate,” says Sonja Dümpelmann, a University of Pennsylvania professor and Landscape Historian and author of Seeing Trees: A History of Street Trees in New York City and Berlin. In her book, she explains how the planting of trees in cities to serve specific functions is not a new phenomenon.
“Tree planting is one of many measures needed to mitigate the climate and provide equal access to nature,” says Dümpelmann. “However, there is not one model, or pattern that can be applied everywhere. Different species have different needs and provide different effects in different locations,” she says.
Valuing Trees and Their Caretakers
“It is the mature trees that provide most of the ecosystem services. Careful tree management that includes planting plans, regular surveys, and appropriate care therefore is crucial. Valuing trees goes hand in hand with valuing those who handle, work with, and study them. Careers in urban forestry and arboriculture, as well as training in these fields, need to be valued and compensated accordingly,” says Dümpelmann.
Urban reforestation is recognized as one of the most effective ways to increase cities’ resiliency to climate change and to provide numerous health and social benefits to residents. But the movement to plant trees systematically and comprehensively in cities was born in the 19th century, both in Europe and in the US. Dümpelmann will talk about the origins of urban greening and what we can learn today from more than a century of these efforts in her “Tree Talk: On the Nature, Culture, and Politics of Street Tree Planting” on Wednesday, October 14 at 5 p.m. Register here for this virtual presentation.
Philadelphia and Its Tree History
Trees have always been an important part of Philadelphia. One of the earliest city maps showing street trees dates back to the late 18th century. Trees along the Benjamin Franklin Parkway were planted in memory of World War I soldiers killed in the conflict. In 1989, 219 red oak trees lining the boulevard were removed because they had become too unhealthy due to repeated collisions from cars, disease, and nails used to post notices. In their place, red oak, red maple, and sweet gums were planted so it would no longer be an arboreal monoculture.
Leading the way for trees in Philadelphia is Mindy Maslin, PHS Tree Tenders Program Manager and program founder. Maslin got the idea for a citizen stewardship program while she was attending a tree conference in Chicago in 1991. “I fell in love with the idea, and immediately knew that this was what Philadelphia needed,” she says. “We needed a program that empowered citizens to take the lead in organizing their own neighborhoods. Almost thirty years later, it seems to have worked,” says Maslin. Every planting season, about 60 Tree Tenders groups throughout the region participate by planting and caring for hundreds of trees.
Since the creation of this program in 1993, PHS Tree Tenders have cared for more than 1,600 trees annually. Tree Tenders learn tree biology and identification, as well as proper planting and care. In the process, strong friendships are formed where residents work together, side by side, towards a common goal. Tree Tenders Basic Training courses are offered two times per year through PHS.
Tree Checkers For Long-Term Success
The Tree Checkers monitoring program for new trees was launched in 2011 by Maslin as an extension of the PHS Tree Tenders program. “We have always had an ethic of checking on and caring for trees after planting, but there wasn’t always a system for reminding homeowners of their tree’s needs, recording tree health information, and for scientifically measuring what they were finding,” says Maslin.
At the 2010 Partners in Community Forestry Conference in Philadelphia, Maslin learned of a tree monitoring program run by Friends of Trees in Portland, Oregon. “It seemed like the perfect tool for Tree Tenders in the summer months to engage homeowners in caring for their trees, collect data to follow-up with trees, and produce a list of any dead trees that needed replacement the following planting season,” she says.
In its ninth year, the Tree Checkers program is going strong at PHS. “We can't just plant hundreds, or thousands of trees, each year and walk away and never look back,” says Dana Dentice, PHS Trees Program Manager. “Many won't make it beyond their first year or two — the time it take trees to establish themselves and regrow all the roots they lost back in the nursery field —without some initial TLC from their human caretakers.”
“How do we know if our infant, toddler, or even adolescent and mature trees, are getting the proper care they need to thrive and meet our ever-growing human demand for healthier and cooler neighborhoods,” asks Dentice. This is where long-term tree monitoring and PHS’s Tree Checkers program plays a critical role. “Repeat assessments of the health of a tree allows us to address certain needs throughout the course of its life,” she says. “When you combine the individual assessments, performed following rigorous standards, for a cohort or population of trees it paints a really good picture of performance of certain types of trees, as well as the program’s best practices to plant and steward those trees.” Dentice reports that current data collected indicates up to a 94% survival of our Philadelphia street trees in their first summer after planting — a success!
Support PHS’s More Trees Please Campaign
Trees help reduce rates of asthma, crime, and even premature deaths in cities. Philadelphia currently has 20% tree coverage, with some neighborhoods having less than 5% coverage -- where 30% is ideal for urban areas. Less than 30% tree coverage means hotter temperatures, more run-off pouring pollutants into our rivers and streams, and healthy lives being negatively affected. PHS is committed to partnering with Philadelphia Parks and Recreation, the US Forest Service, and other partners to chart a path forward to meet and sustain our city’s tree canopy at the 30% goal -- but we need your time and support. Please consider making a gift to PHS’s More Trees Please campaign.