Helping urban trees to adapt to climate change
Adaptation of Urban Trees to Climate Change through Superior Genetics and Modified Soils
Almost 80 percent of the U.S. population lives in urban areas and depends on the essential ecological, economic, and social benefits provided by urban trees and forests. This project strengthens the health of trees in cities by evaluating and carefully selecting suitable tree species, and by transforming compact urban soils to help trees thrive long-term in a challenging environment.
Almost 80 percent of the U.S. population lives in urban areas and depends on the essential ecological, economic, and social benefits provided by urban trees and forests. In the U.S. alone, urban trees store over 708 million tons of carbon, and they can help further reduce emissions by lowering electricity demand for summer air conditioning and winter heating. However, urban soils are often unproductive due to high bulk density, low organic matter, poor structure, and low water-holding capacity. These characteristics diminish soil health and create an environment inhospitable to plant growth. Moreover, as climate change worsens, increased summer heat stress is predicted, and new strategies for urban tree selection and management are needed now if we are to prepare for these challenges.
We sought strategies to strengthen the health of urban trees and forests in two ways: selecting tree species that are better able to grow under extreme weather events, and mitigating disturbed urban soils to reduce stress on plants. We continued development of an improved method for determining a tree’s drought tolerance, as well as researched the ability of trees to adapt to drought conditions, by simulating limited water availability under controlled conditions. We also continued to research the Scoop & Dump (S&D) process of soil remediation, which consists of digging-out compacted urban soils and incorporating large amounts (33% by volume) of compost, as well as topping soils with mulch once a year.
We found that fifteen hybrid oak species have increased insect and disease resistance, drought tolerance, good form, and tolerance to alkaline soils. These species were able to cope after drought events, while other trees dropped their leaves to reduce water losses. We have provided 230 trees to communities in New York State for further, long-term evaluation. The Scoop & Dump soil remediation technique has shown to increase the volume of soil usable for trees, while increasing soil quality both in landscape beds and along streets. We also developed a Soil Health Manual for Urban Landscapes, to assist municipalities in assessing and protecting their urban trees and forests; this work is crucial for storm water management, pollution relief, urban heat island mitigation, and human well-being. Over the past two years, we have disseminated our research findings via 25 presentations and workshops, with attendees including Cornell Cooperative Extension educators, urban foresters, nursery professionals, and arborists.
Website: Urban Horticulture Institute
- Funding Source: McIntire-Stennis
- Statement Year: 2020
- Status: Completed project
- Topics: Trees, urban, climate change, sustainability