North Carolina State University study: Dying trees in cities? Blame it on the pavement

10 Mar

The Nature Conservancy published How Urban Trees Can Save Lives:

The Planting Healthy Air report documents which cities stand to benefit most from tree plantings, in terms of both heat and PM reduction, and how much investment would be required to achieve meaningful benefits.
The analysis found that investing just US$4 per resident in each of these cities in tree planting efforts could improve the health of millions of people, and that trees are as cost-effective as many other common solutions.
Most of the cooling and filtering effects created by trees are fairly localized, so densely populated cities—as well as those with higher overall pollution levels—tend to see the highest overall return on investment (ROI) from tree plantings…. https://global.nature.org/content/healthyair

Urban trees can affect the quality of life and health.

Science Daily reported in Why people reject city trees: Study explains why thousands of Detroit residents rejected city’s tree planting efforts:

Trees are a hallmark of vibrant neighborhoods. So why did nearly one-quarter of eligible residents in Detroit, Michigan, turn down free street trees? That’s the mystery University of Vermont researcher Christine Carmichael solves in one of the first studies to explore opposition to city tree planting programs.
As cities from New York to L.A. embark on major tree planting initiatives, the research helps to explain why more than 1,800 of 7,425 eligible Detroit residents — roughly 25% — submitted “no-tree requests” between 2011 and 2014 alone. The study was published January 7 by Society and Natural Resources journal.
“This research shows how local government actions can cause residents to reject environmental efforts — in this case, street trees — that would otherwise be in people’s interests,” says Carmichael, a postdoctoral researcher at UVM’s Gund Institute for Environment and Rubenstein School of Environment and Natural Resources.
Carmichael found that the opposition in Detroit resulted primarily from negative past experiences with street trees, particularly in low-income neighborhoods grappling with blight from vacant properties. In 2014 alone, the city had an estimated 20,000 dead or hazardous trees, following the contraction of Detroit’s once-massive tree maintenance program from budget cuts and population decline.
For many long-term residents, wariness of the new trees was driven by past experiences of caring for vacant properties in their neighborhood. They believed responsibility for maintaining the trees would eventually fall to them. “Even though it’s city property, we’re gonna end up having to care for it and raking leaves and God knows whatever else we might have to do,” said one woman interviewed for the study.
Carmichael also found that skepticism of the program was tied to wider distrust of the city government and outside groups in parts of Detroit. As a result, residents wanted greater decision-making power in selecting which trees to plant in particular locations, adds Carmichael who completed the three-year study for her PhD with co-author Maureen McDonough of Michigan State University…. https://www.sciencedaily.com/releases/2019/01/19010714

A North Carolina State University study suggests that urban areas may require different development and management strategies than forests.

Science Daily reported in Dying trees in cities? Blame it on the pavement:

A North Carolina State University study examining urbanization, scale-insect abundance and latitudinal warming on tree health in the Southeast captured a few surprising results.
The study showed more scale insects on red maple trees in the midrange of eight cities within a 10-degree latitudinal difference, from Newark, Delaware, to Gainesville, Florida….
“Impervious surfaces — basically concrete and pavement — near trees was a better predictor of scale-insect abundance than temperature, and thus a better predictor of poor tree health in the study area,” said Michael Just, an NC State postdoctoral entomology researcher and corresponding author of a paper describing the research.
The finding was surprising, Just said, as the study’s original hypothesis predicted higher scale-insect abundance at lower latitudes — the study’s southernmost areas.
“What we’ve learned over the years in natural areas like forests didn’t translate in this study, which means we may need to consider if other natural-system theories can be used in urban areas,” Just said. “That’s important if we want to have reliable predictive ecological models.” https://www.sciencedaily.com/releases/2019/03/190304140852.htm

Citation:

Dying trees in cities? Blame it on the pavement
Date: March 4, 2019
Source: North Carolina State University
Summary:
A new study of urban tree life in the Southeast shows pavement and concrete may have a bigger effect than longitudinal warming.

Journal Reference:
Michael G. Just, Adam G. Dale, Lawrence C. Long, Steven D. Frank. Urbanization drives unique latitudinal patterns of insect herbivory and tree condition. Oikos, 2019; DOI: 10.1111/oik.05874

Here is the press release from North Carolina State:

PUBLIC RELEASE: 4-MAR-2019

Dying trees in cities? Blame it on the pavement

NORTH CAROLINA STATE UNIVERSITY
A North Carolina State University study examining urbanization, scale-insect abundance and latitudinal warming on tree health in the Southeast captured a few surprising results.
The study showed more scale insects on red maple trees in the midrange of eight cities within a 10-degree latitudinal difference, from Newark, Delaware, to Gainesville, Florida.
Cities in that midrange, including Raleigh and Asheville, showed poorer tree health, due mostly to these high volumes of tree-destroying gloomy scale insects (Melanaspis tenebricosa), which appear as tiny bumps on tree branches and leaves.
“Impervious surfaces – basically concrete and pavement – near trees was a better predictor of scale-insect abundance than temperature, and thus a better predictor of poor tree health in the study area,” said Michael Just, an NC State postdoctoral entomology researcher and corresponding author of a paper describing the research.
The finding was surprising, Just said, as the study’s original hypothesis predicted higher scale-insect abundance at lower latitudes – the study’s southernmost areas.
“What we’ve learned over the years in natural areas like forests didn’t translate in this study, which means we may need to consider if other natural-system theories can be used in urban areas,” Just said. “That’s important if we want to have reliable predictive ecological models.”
###
The study appears in the journal Oikos.
Steven Frank, an NC State professor of entomology, and Lawrence Long, an NC State entomology graduate student, co-authored the paper along with Adam Dale from the University of Florida.
Funding for the study was provided by the U.S. Department of Agriculture National Institute of Food and Agriculture funded Southern IPM Center, under Agreement No. 2014-70006-22485, as well USDA NIFA award Nos. 2013-02476 and 2016-70006-25827. It was also supported by Cooperative Agreement G15AP00153 from the U.S. Geological Survey.
Note: An abstract of the paper follows.
“Urbanization drives unique latitudinal patterns of insect herbivory and tree condition”
Authors: Michael Just, Lawrence Long and Steven Frank, NC State University; Adam Dale, University of Florida
Published: Feb. 15, 2019 in Oikos
DOI: 10.1111/oik.05874
Abstract: Urban landscapes are characterized by high proportions of impervious surface resulting in higher temperatures than adjacent natural landscapes. In some cities, like those at cooler latitudes, trees may benefit from warmer urban temperatures, but trees in many cities are beset with problems like drought stress and increased herbivory. What drives patterns of urban tree health across urbanization and latitudinal temperature gradients? In natural systems, latitude-herbivory relationships are well-studied, and recent temperate studies have shown that herbivory generally increases with decreasing latitudes (warmer temperatures). However, the applicability of this latitude-herbivory theory in already-warmed urban systems is unknown. In this study, we investigated how the interaction of urbanization, latitudinal warming, and scale insect abundance affected urban tree health. We predicted that trees in warmer, lower latitude cities would be in poorer health at lower levels of urbanization than trees at cooler, higher latitudes due to the interaction of urbanization, latitudinal temperature, and herbivory. To evaluate our predictions, we surveyed the abundance of scale insect herbivores on a single, common tree species Acer rubrum in eight US cities spanning 10° of latitude. We estimated urbanization at two extents, a local one that accounted for the direct effects on an individual tree, and a larger one that captured the surrounding urban landscape. We found that urban tree health did not vary with latitudinal temperature but was best predicted by local urbanization and herbivore abundance. We did not observe increased herbivore abundance in warmer, lower latitudes cities, but instead herbivore abundance peaked in the mid latitudes of our study. This study demonstrates that urban landscapes may deviate from classical theory developed in natural systems and reinforces the need for research reconciling ecological patterns in urban landscapes.
Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.
Media Contact
Michael Just
mjust@ncsu.edu

@NCStateNews
http://www.ncsu.edu

The Royal Parks of the United Kingdom summarized the benefits of urban trees. The Royal Parks wrote in Why are trees so important?

Trees are vital. As the biggest plants on the planet, they give us oxygen, store stabilise the soil and give life to the world’s wildlife. They also provide us with the materials for tools and shelter.
Not only are trees essential for life, but as the longest living species on earth, they give us a link between the past, present and future.
It’s critical that woodlands, rainforests and trees in urban settings, such as parks, are preserved and sustainably managed across the world….
Trees benefit health
The canopies of trees act as a physical filter, trapping dust and absorbing pollutants from the air. Each individual tree removes up to 1.7 kilos every year. They also provide shade from solar radiation and reduce noise….
Trees benefit the environment
Trees absorb carbon dioxide as they grow and the carbon that they store in their wood helps slow the rate of global warming.
They reduce wind speeds and cool the air as they lose moisture and reflect heat upwards from their leaves. It’s estimated that trees can reduce the temperature in a city by up to 7°C.
Trees also help prevent flooding and soil erosion, absorbing thousands of litres of stormwater.
Trees boost wildlife
Trees host complex microhabitats. When young, they offer habitation and food to amazing communities of birds, insects, lichen and fungi. When ancient, their trunks also provide the hollow cover needed by species such as bats, woodboring beetles, tawny owls and woodpeckers.
One mature oak can be home to as many as 500 different species. Richmond Park is full of such trees, which is one of the reasons it has been designated a National Nature Reserve and Site of Special Scientific Interest.
Trees strengthen communities
Trees strengthen the distinctive character of a place and encourage local pride. Urban woodland can be used as an educational resource and to bring groups together for activities like walking and bird-watching. Trees are also invaluable for children to play in and discover their sense of adventure.
Trees grow the economy
People are attracted to live, work and invest in green surroundings. Research shows that average house prices are 5-18% higher when properties are close to mature trees. Companies benefit from a healthier, happier workforce if there are parks and trees nearby.
Trees protect the future
Soon, for the first time in history, the number of people with homes in cities will outstrip those living in the countryside. Parks and trees will become an even more vital component of urban life. We must respect them and protect them for the future…. https://www.royalparks.org.uk/parks/the-regents-park/things-to-see-and-do/gardens-and-landscapes/tree-map/why-trees-are-importantcarbon,

See, Envisioning a Great Green City: Nature needs cities. Cities need nature. https://www.nature.org/en-us/what-we-do/our-insights/perspectives/envisioning-a-great-green-city/

Resources:

Urban Forestry & Energy Conservation Bibliography https://articles.extension.org/pages/71120/urban-forestry-energy-conservation-bibliography

Urban Forestry Bibliography Created by the Forest Service … https://www.milliontreesnyc.org/downloads/pdf/urban_tree_bib.pdf

Where information leads to Hope. © Dr. Wilda.com

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http://drwildareviews.wordpress.com/

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