ADAPTING OUR URBAN FORESTS TO A CHANGING CLIMATE Leslie Brandt, PhD

Climate Change Specialist

URBAN FORESTS

All publicly and privately owned trees within an urban area— including

individual trees along streets and in backyards, as well as stands of remnant

forest (Nowak et al. 2001).

ENERGY USE

Reduced cooling from shade Reduced heating from windbreaks

Annual economic value: $2.8 million

WATER QUALITY AND FLOW Precipitation

Evapotranspiration

Stemflow

Throughfall

$3.4 million annual value for stormwater runoff reductions

COMMUNITY RESILIENCE

URBAN FORESTS: A CLIMATE ADAPTATION STRATEGY?

Ten-Year Urban Forestry Action Plan: 2016 -2026

National Urban and Community Forestry Advisory Council

Cities that include trees as part of their climate

change/sustainability goals in climate action plans

States that have developed comprehensive Climate Action

Plans, using forests to help adapt/mitigate

Cities that view trees as part of their overall

sustainability/climate protection efforts

ST. PAUL’S URBAN FOREST

Over $10 million in benefits (energy reduction, stormwater, aesthetic, air quality)

32.% Canopy Cover:

• 66.2% of Saint Paul is suitable for tree canopy cover

• Residential, single-family parcels offer the greatest opportunity

Species Composition:

• 1 in 5 city trees is an ash tree (EAB)

• Maples make up a similar percentage.

Source: https://www.stpaul.gov/departments/parks-recreation/natural-resources/forestry/urban-tree-canopy

IMPACTS

HARDINESS ZONE PROJECTIONS Low emissions High emissions

5a-5b

5b-6b

5b-7a

Now: Zone 4

STRESSORS

Drought Flooding

Storms Disease

LOSING SUITABLE HABITAT

http://www.fs.fed.us/nrs/atlas/

Paper birch Balsam fir Black spruce

White spruce White pine

LOSING SUITABLE HABITAT

Sugar Maple

American linden/basswood

Chokecherry

http://www.fs.fed.us/nrs/atlas/

GAINING HABITAT

Wild plum

Eastern redbud

Ohio buckeye

HOW DO WE ADAPT?

ADAPTATION OPTIONS

Reduce impacts/ Maintain current

conditions

Forward-looking/ Promote change

Resistance Transition Resilience

THINGS YOU CAN DO AT HOME Resist change:

• Water during hot, dry periods

• Using systematic insecticides for ash trees on private property

• Protect/maintain cold-adapted trees on the north side of buildings/north facing slopes

THINGS YOU CAN DO AT HOME Build resilience:

• Increase biodiversity-plant something different!

• Plant trees and other native plants that can withstand a variety of stressors (drought, flooding, wind)

• Prune to reduce susceptibility to storm damage

• Plant trees at the proper depth

THINGS YOU CAN DO AT HOME

Facilitate transitions

• rain gardens

• rain barrels

• Plant southern species

• Plant prairie plants in hot, sunny spots

URBAN FORESTRY CLIMATE CHANGE RESPONSE FRAMEWORK

Brandt et al. 2016. Environmental Science and Policy

EXAMPLE: HENNEPIN COUNTY

20

Gravel bed nursery-builds root structure, reduces cost, ensures proper planting

Species selection-southern species (zones 5, 6), growing hickory from seed

LEARN MORE www.forestadaptation.org/urban

lbrandt@fs.fed.us