Seeing the Urban Forest for the Trees
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1. Urbanization is increasing globally, with more people living in urban areas, which leads to issues like increased energy use and air pollution. Trees can help address some of these issues by providing shade, improving air quality, and sequestering carbon. 2. Nature and urban populations interact in cities, as trees grow both through natural regeneration and planting. However, costs are unavoidable to maintain trees and infrastructure. 3. The urban forest and tree cover is facing threats from development, climate change, pests and diseases, and invasive species, which could reduce tree cover in cities by thousands of acres each year. Proper planning, assessment, and monitoring are needed to sustain urban forests into the future.
Seeing the Urban Forest for the Trees
- 1. Seeing the Urban Forest for the Trees David J. Nowak US Forest Service Syracuse, NY
- 2. Early Morning Test – What is this?
- 5. Perception of Value We take care of things we value New red car – What are you willing to pay? Ferrari 488 GTB - Features: Twin-turbocharged 3.9-liter V8, 660 horsepower Yugo - Features: Rear-window defogger so owner can keep hands warm while pushing vehicle
- 6. Five General Messages about Urban Forests There are global problems
- 7. Urbanization World = 54% urban (3.9 billion urban inhabitants) By 2050 = 66% urban (6.4 billion urban inhabitants) www.globalchange.umich.edu
- 8. Projected urban land increase (2010-2060): +2 million acres/year Urban land (conterminous U.S.) 2010 = 67.8 million acres (3.6%) 2060 = 163.1 million acres (8.7%) Increase greater than size of Montana Urban population increase Approximately 90% urban population (2060) Delaware land area = 1.2 million acres
- 9. Growth in Percent Urban (2010 – 2060)
- 10. Urbanization Issues – Energy Use One trillion BTU =~ 250,000 tonnes of TNT Daily world energy use = 60 million tons of coal = pile of coal: 10 ft x 1 mile x 4.4 miles theenergyharginger.com
- 11. Urbanization Issues – Air Pollution 3.7 million deaths from outdoor air pollution (2012) World’s largest single environmental health risk Air pollution mortality (2010) – Nature, 2015
- 12. Urbanization Issues - Others Increased air temperatures Water flow / quality issues Crowding Stress… Source: NASA: Bright red = 65oC; Dark green / blue ~ 25oC
- 13. Five General Messages about Urban Forests There are global problems Trees can help
- 14. Tree Benefits - Tangible Shade / Cool Air Aesthetics Wildlife
- 15. Tree Benefits – Less Tangible Pocket book ($) Altered building energy use / altered emissions Products (26M t wastewood/yr), jobs Human Health Water quality Air quality, UV radiation Physiological changes Environmental Quality / Regulations Air quality, water quality, carbon, air temperature Other Biodiversity, neighborhoods, crime…
- 16. Tree Costs Maintenance / planting / removal Leaf clean-up Damaged sidewalks Blocked views Branch drop Crime perception Pollen Increased energy use VOC emissions Maintenance emissions, pesticides, excess fertilization
- 17. Annual U.S. Urban Forest Values > $18 billion/yr Avoided energy use = $7.8 billion* 39 million Mwh/year; 246 million MMBTU /year Air pollution removal = $4.7 billion 717,000 tons/year; ~580 avoided deaths / year Carbon sequestration = $3.7 billion 29.4 million tons / year Avoided emissions = $2.2 billion* 21.5 million t CO2; 93,000 t pollutants /year Oxygen production = $0 75 million tons per year Total = $18.4 billion $770 per acre of tree cover *preliminary results
- 18. Five General Messages about Urban Forests There are global problems Trees can help Nature and people interact
- 19. Tree Cover Urban / Community Land ~80% of U.S. urban land is within forested areas
- 20. Nature and Humans What percent of trees in cities are planted? Nowak, D.J. 2012. Contrasting natural regeneration and tree planting in 14 North American cities. Urban Forestry and Urban Greening. 11: 374 – 382
- 21. Planting varies by city population density and region Nowak, D.J. 2012. Contrasting natural regeneration and tree planting in 14 North American cities. Urban Forestry and Urban Greening. 11: 374 – 382
- 22. Percent planting varies by land use Nowak, D.J. 2012. Contrasting natural regeneration and tree planting in 14 North American cities. Urban Forestry and Urban Greening. 11: 374 – 382
- 23. Percent of Total Tree Cover in Cities by Land Use Forest (40% TC) Grass (20% TC) Desert (10% TC)
- 24. Why Don’t We Have More Urban Trees?
- 25. Why Don’t We Have More Urban Trees? It is expensive to keep trees out US mowing ~$49-134 billion / year
- 26. Why Don’t We Have More Urban Trees? It is expensive to keep trees out
- 27. Five General Messages about Urban Forests There are global problems Trees can help Nature and people interact Costs are unavoidable
- 28. Costs are Unavoidable People in association with trees = costs Goal = reduce costs; increase values No trees ≠ no costs Costs of gray infrastructure and mowing
- 29. What if we didn’t maintain gray infrastructure?
- 30. What if we didn’t maintain gray infrastructure?
- 31. Five General Messages about Urban Forests There are global problems Trees can help Nature and people interact Costs are unavoidable Change is coming
- 32. Major Drivers of Change in the Future Development
- 33. Major Driver of Change in the Future Development Climate Change
- 34. Major Driver of Change in the Future Development Climate Change Insects and Diseases Emerald ash borer range (2013) Ash dieback (Hymenoscyphus fraxineus)
- 35. Major Driver of Change in the Future Development Climate Change Insects and Diseases Invasive species
- 36. Tree Cover Change In the U.S., urban tree cover dropping: 20,000 acres per year 4.0 million trees per year
- 37. Steps to Sustainability Assess resource – what do you have? Understand resource – what can it do? Plan – what do you want? Right location, right tree, right time; across scales Implement Plan Monitor – did you get there?
- 39. Summary dnowak@fs.fed.us nrs.fs.fed.us/units/urban Trees and forests provide significant value to society Understanding and communicating the resource value is essential to improve management and community well-being