seeing the urban forest for the trees

Seeing the Urban Forest

for the TreesDavid J. Nowak

US Forest Service

Syracuse, NY

Early Morning Test – What is this?

Perception of ValueWe 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

Five General Messages about Urban Forests

There are global problems

UrbanizationWorld = 54% urban (3.9 billion urban inhabitants)

By 2050 = 66% urban (6.4 billion urban inhabitants)

www.globalchange.umich.edu

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

Growth in Percent Urban (2010 – 2060)

Urbanization Issues – Energy Use

One trillion BTU =~ 250,000 tonnes of TNTDaily world energy use = 60 million tons of coal

= pile of coal: 10 ft x 1 mile x 4.4 miles

theenergyharginger.com

Urbanization Issues – Air Pollution3.7 million deaths from outdoor air pollution (2012)

World’s largest single environmental health risk

Air pollution mortality (2010) – Nature, 2015

Urbanization Issues - Others

Increased air temperatures

Water flow / quality issues

Crowding

Stress…

Source: NASA: Bright red = 65oC; Dark green / blue ~ 25oC

Five General Messages about Urban Forests

There are global problems

Trees can help

Tree Benefits - TangibleShade / Cool Air

Aesthetics

Wildlife

Tree Benefits – Less TangiblePocket 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…

Tree CostsMaintenance / planting / removal

Leaf clean-up

Damaged sidewalks

Blocked views

Branch drop

Crime perception

Pollen

Increased energy use

VOC emissions

Maintenance emissions, pesticides, excess fertilization

Annual U.S. Urban Forest Values > $18 billion/yrAvoided 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

Five General Messages about Urban Forests

There are global problems

Trees can help

Nature and people interact

Tree Cover Urban / Community Land

~80% of U.S. urban land is within forested areas

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

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

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

Percent of Total Tree Cover in Cities by Land Use

Forest(40% TC)

Grass(20% TC)

Desert(10% TC)

Why Don’t We Have More Urban Trees?

Why Don’t We Have More Urban Trees?

It is expensive to keep trees out

US mowing ~$49-134 billion / year

Why Don’t We Have More Urban Trees?

It is expensive to keep trees out

Five General Messages about Urban Forests

There are global problems

Trees can help

Nature and people interact

Costs are unavoidable

Costs are Unavoidable

People in association with trees = costs

Goal = reduce costs; increase values

No trees ≠ no costs

Costs of gray infrastructure and mowing

What if we didn’t maintain gray infrastructure?

What if we didn’t maintain gray infrastructure?

Five General Messages about Urban Forests

There are global problems

Trees can help

Nature and people interact

Costs are unavoidable

Change is coming

Major Drivers of Change in the Future

Development

Major Driver of Change in the Future

Development

Climate Change

Major Driver of Change in the Future

Development

Climate Change

Insects and DiseasesEmerald ash borer range (2013)

Ash dieback (Hymenoscyphusfraxineus)

Major Driver of Change in the Future

Development

Climate Change

Insects and Diseases

Invasive species

Tree Cover Change

In the U.S., urban tree cover dropping:

20,000 acres per year

4.0 million trees per year

Steps to SustainabilityAssess 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?

Demonstrating Tree Value

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