Into the Woods: How and Why We Manage Our Forests

David Donovan

MN GreenCorps Member

Green Infrastructure – Urban Forestry

Three Rivers Park District

Trees are good…

• Sequester/store carbon

• Reduce GHG

• Remove air pollutants

• Mitigate storm water

• Lessen energy use

…But I don’t have to tell you that.

Sometimes it’s not as obvious…

• Wildlife habitat

• Public health – Physical

– Social/Psychological¹

• Aesthetic worth

• Added property value

• Boost commerce²

• Crime reduction³ ¹ Taylor (2001) ² Wolf (1999) ³ Kuo (2003)

How do we study this?

• Tree inventory

– Forest structure, species composition

– Overall health (disease, invasiveness)

– Significance of ecological services

– Estimated economic (compensatory) value

Assist in guiding management practices

of a forest system

What/how much is there?

i-Tree Eco

• Developed by USDA Forest Service

• Provides a broad picture of entire urban forest

• Analyzes data regarding:

– Inventory fieldwork

– Local meteorology

– Pollution levels

Three Rivers Inventory Project

Active Use Areas

• Areas of recreation (picnic sites, playgrounds, camping)

• Complete inventory

• Each tree plotted, various attributes recorded

Natural Areas

• Off-trail, undeveloped, relatively undisturbed areas

• Sample inventory

• Survey random plots, extrapolate to rest of Parks

Setting Up the Project

• Geographic Information Systems (GIS)

• Estimate 10,241 forested acres in Park District

• Stratified random sample of plots for natural areas

• Selected and inventoried 20 sites for a total of:

– 760 trees inventoried

– 23 species identified

Snapshot of Combined Results

• Across both inventories:

– 7,831 trees inventoried

– 61 species identified

– Average diameter (DBH) 12 inches

– Average height 38 feet

– Potential health concerns 1,348 (17%)

Charly Kearns

MN GreenCorps Urban Forestry

2010-2011

Preliminary Results, 2010-11

• Three Rivers Project Estimates: – 3.8 million trees

– 89% canopy cover

– Pollution removed: 450 mt/y

– Carbon stored: 422,000 mt

– Carbon sequestered: 15,800 mt/y

Total compensatory value of trees within Three Rivers Park District:

$1.44 billion

$3.66 million/y

$8.57 million

$321,000/y

Relative Magnitudes

• Carbon sequestered annually:

– 10,500 automobiles

– 5,300 single family houses

– 15 days of area emissions

• Compared to other places:

Number of Trees

Carbon Storage

(mt)

Carbon Sequestration

(mt/y)

Pollution Removal (mt/y)

Three Rivers Park District

3,886,000 422,000 15,800 326

Baltimore, MD 2,627,000 541,000 14,600 390

Philadelphia, PA 2,113,000 481,000 14,600 523

Managing to Manage

• Mission:

– To promote environmental stewardship through recreation and education in a natural resources-based park system.

• Natural Resource Management

– Restore and protect natural resources

• Forestry

• Water Resources

• Wildlife

Three Rivers Forestry • Sow native tree and shrub seeds

• Plant seedlings and large bare root trees

• Remove exotic species to allow succession

• Maintain trees and shrubs in active use areas

• Monitor and control disease and insects (oak wilt, gypsy)

• Lessen landscape damage due to animals (deer, vole)

• Utilize mulch with leaves from neighboring cities

Current 2011-12 Season Goals

• Natural Area Inventory – More robust sample size

– > Double plots posted

– 100% survey of posted plots

• Active Use Area Inventory – Continue and expand

– Update plantings/removals

2010-11 2011-12

Plots Posted 43 100

Plots Surveyed 20 In Progress

Your Part in Urban Forestry

• Plant native species! – Sustains native wildlife

– Reduces water consumption

– Controls soil erosion

– Improves water quality

– Mitigates flooding and drought

– Slows wildfire spread

– Preserves natural heritage

• Control spread of exotic species