Why Trees?

Trees, especially urban trees, provide many tangible benefits to California.


  1. Nowak, David J. and Eric J. Greenfield. Urban and Community Forests of the Pacific Region: California, Oregon, Washington. US Forest Service. October 2009. Web.
  2. Development of GHG Efficiency Benchmarks for the Distribution of Free Emissions Allowances in the Cap-and-Trade Program.” California Air Resources Board. California Air Resources Board, 20 August 2012: 6. Print.
  3. McPherson, Greg. Urban Forestry Economics Fact Sheet. 2012. Microsoft Excel file.
  4. Geiger, J.R. Trees – The Air Pollution Solution. Center for Urban Forest Research. January 2006.
  5. Xiao Q., and E.G. McPherson. Rainfall interception by Santa Monica’s municipal urban forest. Urban Ecosystems. 2003.
  6. McPherson, E.G. and J.R. Simpson. 2001. Effects of California’s urban forests on energy use and potential savings from large-scale tree planting. Davis, CA: USDA Forest Service, Pacific Southwest Research Station, Center for Urban Forest Research
  7. Wolf, K.L. 2008. City Trees, Nature and Physical Activity: A Research Review. Arborist News 17, 1:22-24.
  8. Melvin, John. Urban Forestry Economics Fact Sheet. California Department of Forestry and Fire Protection. Web. February 2013.
  9. Wolf, K.L. 2010. Community Economics – A Literature Review. Green Cities: Good Health. College of the Environment, University of Washington. Web. February 2013.

Trees improve the quality of the air we breathe.

Trees remove carbon dioxide from the air by sequestration.

Trees filter air pollutants, including ozone and particulates.

Trees produce life-supporting oxygen.

This recent study from the US Forest Service Northern Research Station suggests that trees’ improvements to air quality help humans avoid more than 850 deaths and more than 670,000 instances of acute respiratory symptoms in a given year!

Trees help Californians store, clean, process, and save water.

Trees help keep our waterways clean by reducing stormwater run-off and soil erosion.

Trees filter chemicals and other pollutants from water and soil.

Trees intercept rainfall, which protects against flash flooding and recharges groundwater supplies.

Trees need less water than lawns, and the moisture they release into the air can significantly reduce the water requirements of other landscape plants.

Trees conserve energy, making our buildings, systems, and properties more efficient.

Trees mitigate urban heat island effects by providing shading.

Trees provide shade, moisture and windbreaks, decreasing the amount of energy needed to cool and heat our homes and offices.

Trees increase mental and physical health for people at every age.

Trees create a desirable environment for outdoor physical activity and encourage active lifestyles.

Trees reduce symptoms or incidence of attention deficit and hypertension disorder (ADHD), asthma, and stress.

Trees reduce exposure to UV radiation, thus reducing the risk of skin cancer.

Tree views can speed the recovery time for patients recovering from medical procedures.

Trees produce fruit and nuts to contribute to healthy diets.

Trees create a setting for neighbors to interact, strengthen social ties and create more peaceful and less violent communities.

Trees contribute to the overall physical, mental, and social well-being of individuals and communities.

Check out the Green Cities: Good Health website for a comprehensive collection on studies showing the connection between trees and human health.

Trees create employment opportunities for people to start, develop, and succeed in their careers — making California’s cities and towns better places to live, work, and play.

  • There are more than 50 million sites available for planting new trees and approximately 180 million trees in need of care in California’s cities and towns. With plenty of work to be done, California can continue job creation and economic growth by investing in urban and community forests today.
  • Urban forestry projects provide critical training to young adults and at-risk youth along with opportunities in the public works sector. Additionally, urban forestry care and management create both public and private sector jobs while also creating a healthier, cleaner, and more livable environment for decades to come.
  • See the economic value of trees on CAL FIRE’s Urban Forestry Economic Impacts Fact Sheet.
  • Check out 50 Careers in Trees you can have from the Tree Foundation of Kern
  • Search for tree jobs on our California ReLeaf Job Postings or at the ACTrees Jobs Center
  • Learn how California ReLeaf helped create more than 300 jobs and contribute well over 200,000 hours to California’s work force during a time of economic stimulus — read the short story or the long story of our work with the American Recovery and Reinvestment Act in 2009


“Urban Forests are critical to changing the quality of environmental health in our communities; our approach promotes restoration and environmental stewardship.” — Kemba Shakur, Urban ReLeaf Executive Director

“We are taking youth that are on the fringe of being employable, at-risk youth, and giving them training. At the same time they are required to complete their diploma, which makes them competitive in the job market.” — Nathan Higgins, CSET Project Manager

Trees make our communities safer, more valuable, and more fun to be a part of.

Tree planting, care and management generate jobs in both the public and private sectors.

Trees can increase the value of residential property by 10% or more.

Trees can boost business and tourism in commercial areas by providing shadier and more inviting walkways and parking lots.

Trees attract new businesses and residents.

Trees cut costs for heating and cooling and landscape water.

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