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Pener Conference Keynote
City Trees and Country Trees
The keynote address was delivered by BU's Earth and Environment professor, Dr. Lucy Hutyra. Dr Hutyra, a MacArthur Foundation Fellow, has discovered that country trees and city trees of the very same species behave in ways that are significantly different from one another in response to their built and natural environments. While we might "of course they do" to ourselves as we read, Dr. Hutyra's research holds significant implications for selecting climate change mitigation strategies. For example, city trees grow faster and act as larger carbon sinks than their twins growing in a large intact forest such as Harvard Forest. Cities, therefore, just need more trees, right?
Not so fast.
Dr. Hutyra's research finds that "streetscape trees" aren't a panacea for cooling cities and mitigating CO2 emissions. Even though "soils in urban fragmented forests release carbon into the atmosphere at lower rates than fragmented forests in rural areas," and in spite of the fact that "respiration rates in urban forest edges are also less sensitive to temperature increases," planting trees in cities must be the Right Tree, Right Place. City trees "do consume carbon quickly," a fact that works to mitigate our emissions, reports Dr. Hutyra's team. "But, their mortality rates are nearly twice that of rural trees, leading to a net loss of carbon storage over time." Additionally, they require watering, another environmental and economic cost to consider. Understanding all of these variables, including innovative roofing design and materials, Dr. Hutyra informed the students, is important for good science and critical information that leads to better decisions in government and industry.
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