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I've Got You Covered: The Amount of Pavement Covered by Street Trees

This article is from Issue Urban Forest - Vol. 6 No. 1.

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The trees that grow along urban streets are called street trees. Some street trees are planted between the street and the sidewalk. Other street trees are planted in a strip of land called the median, which lies in between the lanes of traffic. Trees that grow in front yards are considered street trees if part of their canopy covers public areas, such as the sidewalk or the street. The scientists in this study wanted to know how much of the sidewalks and streets were covered by tree canopies in a particular urban area. 

Welcome to the Urban Forests edition

Note to Educators

Urban Forest Lesson Plan

Reflection Section Answer Guide

Education Standards Correlations


Meet the scientists that contributed to this article:

"Science Topics" covered in this article:
  • Earth Science
  • Life Science
  • People and Science
  • Technology and Science

"Environmental Topics" covered in this article:
  • Atmosphere (Educators)
  • Forest and Grassland Use (Educators)
  • Growing and Using Trees and Other Plants (Students)
  • Importance of Forest to People (Students)
  • Protecting Trees and Other Plants (Students)
  • The Value of Forests and Grasslands (Educators)
  • Using Forests (Students)

Regions covered in this article:
  • Alaska
  • Forest Products Lab
  • Intermountain
  • International Institute of Tropical Forestry
  • Northern
  • Pacific Northwest
  • Pacific Southwest
  • Rocky Mountain
  • Southern
  • Southwestern

"Thinking About Science Themes" covered in this article:
Scientists work to solve problems. These problems are identified because their solution provides a benefit to people. Sometimes a scientist's research might be a part of a larger problem. By solving a small piece of the problem, scientists can provide information so that the larger problem might one day be solved. In this study, the scientists wanted to know how much of a city's paved surfaces should be covered by trees. Paved surfaces include streets, sidewalks, and parking lots. Many benefits are provided by urban trees when they cover paved surfaces. To answer their question, they first needed a way to estimate the current amount of ground and pavement that urban trees cover. This is because the amount of benefits provided by urban trees is related to the amount of ground and pavement that their canopies cover. Unless the scientists found out how much of the city's paved surfaces were currently covered by trees, they could not determine whether more tree cover was needed.
Specific "Thinking About Science" Themes:
  • Characteristics of Scientists
  • The Scientific Process
  • Uses and Benefits of Science

"Thinking About Environmental Themes" covered in this article:
Urban trees provide many benefits to people and their communities. Urban trees keep areas cooler in the summer, helping to lower energy use in buildings. Trees keep the air cleaner by reducing the amount of harmful pollutants in the air. They also help to prevent global warming by reducing the amount of carbon dioxide going into the atmosphere. Trees hold the soil in place and intercept rainwater. When trees intercept rainwater, they reduce the amount of water that runs into stormdrains and washes pollutants into streams and rivers. Urban trees also provide homes for birds and other urban wildlife and make urban areas more beautiful. Most of these benefits depend on how much of the ground, including paved areas, the tree's canopy covers (figure 1). Usually, the larger the area of ground or pavement that is covered by urban tree canopies, the greater the benefits to people.
Specific "Thinking About the Environment" Themes:
  • Ecosystems

NSE Standards covered in this article:
  • Abilities necessary to do scientific inquiry (A)
  • Nature of science (G)
  • Regulation and behavior (C)
  • Science and technology in society (F)
  • Science as a human endeavor (G)
  • Understandings about scientific inquiry (A)

Science Benchmarks covered in this article:
  • Habits of Mind: Communication Skils
  • Habits of Mind: Computation and Estimation
  • Habits of Mind: Critical-Response Skills
  • Human Society: Social Change
  • Human Society: Social Trade-Offs
  • The Mathematical World: Reasoning
  • The Mathematical World: Symbolic Relationships
  • The Nature of Mathematics: Mathematics, Science, and Technology
  • The Nature of Science: Scientific Inquiry
  • The Nature of Science: The Scientific Enterprise