You don't just need expertise or experience to be an effective steward of urban trees. You need a network.
In my last post I wrote about some of the complexities of using urban trees to both avoid and cope with climate change. To deal with these challenges, we need broadly knowledgeable professionals. From arboriculture to ecology, tree physiology, conservation, urban planning, landscape design, municipal policies, urban infrastructure, and community engagement, planners and managers of urban landscapes contend with all this and more.
The Australian School of Urban Forestry (ASUF) is an annual one-week, intensive program of guest speakers, field trips, and hands-on projects at the leading edge of urban forestry. Organized by Associate Professor Steve Livesley and Dr. Sara Barron of the University of Melbourne, and Ian Shears of the City of Melbourne, ASUF brings together the many different tree and forest stewards across Australian cities.
There are plans to hold ASUF in different areas of Australia over time, but it's currently held in Melbourne. This is a good place to start - as we heard from David Callow, the Director of Parks and City Greening, Melbourne is home to ambitious programs for expanding urban tree cover and engaging communities with greenspace planning. And of course, the city is internationally famous for its "treemail" program (more on that in a bit).
This year, I gave an opening lecture about urban forests and nature-based solutions. But as soon as I saw the program, I knew right away that I didn't just want to be a lecturer - I needed to be a student. So I sat in on the course and listened to innovative practitioners and researchers from all across Australia, and a few from across the world.
There's far too much information in ASUF to fit into a short blog post, but here are a few observations:
Defining urban forestry
What we call urban forestry isn't really a single profession. As pointed out by Susan Day, a professor at the University of British Columbia and program director for one of the few degree programs in urban forestry, people come to hold positions as urban foresters from a wide range of backgrounds, including forestry (most of which is not urban) to ecology, environmental science, policy, horticulture, urban planning, design, and a range of other disciplines. And many people charged with planning, designing, or maintaining urban trees and landscapes don't hold positions that are titled "urban forester" at all.
As an ecologist, I have easy access to scientific organizations like the Ecological Society of America to help with professional development, summarize best practices, organize outreach and education, and provide a clearinghouse of information. But there isn't quite an analogous resource for urban foresters. ASUF is helping to fill this gap with online resources and a forum for all urban tree and forestry stewards and professionals across the country.
The need for stewards of urban trees
There is more written about the benefits of trees than could easily be distilled here, but we can summarize a few points from the evidence to date. First, let's get one issue out of the way: some of the physical effects of trees on the environment have been over-estimated. As I wrote last time, carbon sequestration in urban trees will do very little to mitigate climate change, and many studies are showing that the same is true for other forms of air pollution. This was well described by Theo Eisenman's recent paper on the science of urban trees, air quality, and asthma.
But, having said that, the cooling effects of trees on air temperature are strongly supported by evidence. And there are other intricate and fascinating ways that trees affect human health. The literature on greenspace and health is vast - there are now numerous review papers on the topic and even systematic reviews of reviews. You'd think that given all these papers, we must be very sure about exactly how trees affect urban health. But in fact, most papers conclude that there are still major knowledge gaps, because collaborations between the health and ecological/forestry professions are relatively rare. We know that there are real benefits of proximity to greenness for mental health and some physical health outcomes. And there are intriguing aspects of social well-being - factors like social interactions, connectedness, and feelings of inclusion - that intersect with trees and parks. But data are only available for limited populations and periods of time. We're still just scratching the surface in finding ways to best configure urban forests and greenspace to benefit public health.
This brings us back to the treemail. Melbourne has a user-friendly data portal about its urban forest, and each tree has a unique identifier associated with an email address so that people can report maintenance issues as needed. Except it turns out that people don't just write about maintenance. They write personal messages, poems, jokes, or moving accounts about their experiences with trees. Messages can arrive from overseas from people who have never been to Melbourne, but view the trees online. You can write a message yourself if you want, and be aware: when they feel so inclined, sometimes the trees write back.
Anyone who works with urban trees quickly learns: people are passionate about them. Sometimes they're passionately against tree planting, though I've found it much more common that people are emotionally attached to specific trees, types of trees, or concepts of nature that relate to trees. I think this is extremely important - in the end, regardless of the data on pollution effects, air temperature, or outcomes for cardiovascular health, often we just want trees because, well, we want them. As this blog post put it, the outcomes of the treemail program showed that "there's more to trees than ecosystem services." And as far as I'm concerned, that's reason enough to plant and care for them, if we can do it well.
The urban environment can be a challenging place for both people and trees, but by all indications, we're better off together than apart.
This is why we need urban forestry professionals to develop, implement, and share the best practices for making cities habitable with and for trees. In part 2, we'll hit the streets (and roofs) of Melbourne and look at some creative projects aimed at improving livability and quality of life by expanding and re-designing greenspace.