dysfunctional root systems and brief landscape lives: stem
TRANSCRIPT
Dysfunctional Root Systems and Brief Landscape Lives: Stem Girdling Roots and the Browning of our Landscapes
2010 Woody Plant Conference – Scott ArboretumGary JohnsonThe University of MinnesotaDepartment of Forest Resources
University of Minnesota Urban Forestry and Horticulture Institute (www.trees.umn.edu)
Gary Johnson, Professor and corresponding presenter. [email protected], 612-625-3765. Chad Giblin, Research Scientist Jeff Gillman, Associate Professor Dave Hanson, Research Specialist Rebecca Koetter, Research Fellow Sean Peterson, Forestry Technician Andrea Dierich, Graduate Research Assistant Davin Shokes, Research Assistant Emily Hanson, Research Assistant
University of Minnesota Urban Forestry and Horticulture Institute
Some Average Life Spans
Bur Oak 250+ Years* Silver Maple 125+ Years* Boxelder 100+ Years* Jack Pine 80+ Years* Paper Birch 65+ Years* Ford F150 Truck 20+ Years** Urban Core Tree 7-10 Years***
*Silvics of North America. **I Hope. ***Moll, 1989
State of the Urban Forest – 1989G. Moll, American Forests
Average Tree Lifespans* “Downtown” Urban Trees: 7-10 years. Suburban Landscape Trees: 30-40 years. Rural Landscape Trees: 60-70 years. Native Undisturbed Sites: 150 years.
*Based on J. Kielbaso’s research
“Downtown” Urban Trees
“Suburban” Landscape Tree
“Rural” Landscape Tree
Native Undisturbed Sites
Tree Health Decline: Predisposing, Inciting and Contributing Factors
Predisposing: Chronic effects on health. Inciting: Short-lived, random events. Contributing: Opportunistic factors.
Common Predisposing Factors
Long-Term Drought Cold Hardiness Zones Confined Root Spaces Poorly-Drained Soil
Common Inciting Events
Seasonal Floods Non-Target Spray Drift Weed Trimmer/Lawn Mower Damage Wind Storms
Common Contributing Agents
Armillaria Root Rot Two-Lined Chestnut Borer Bronze-Birch Borer Target Cankers
Dysfunctional Root Systems as Primary Predisposing Factors
Normal Functional Root Systems
Soil Line
Branch Root
Fine Root
6 year sugar maple root system from seed
Normal Functional Root Systems
White spruce root system
Pat Bartlett – Bartlett Forestry
Normal Functional Root Systems
Abnormal but Functional Root Systems: Gravel Bed Root Systems
Abnormal but Functional Root Systems: Adventitious Roots
Dysfunctional Root Systems as Primary Predisposing Factors
Photo by Dave Hanson
Photo by Eric Berg
Dysfunctional Root Systems as Primary Predisposing Factors
Dysfunctional Root Systems as Primary Predisposing Factors
Approximately 20 year old root system of linden
Dysfunctional Root Systems as Primary Predisposing Factors
Dysfunctional Root Systems as Primary Predisposing Factors
Dysfunctional Root Systems as Primary Predisposing Factors
Problems With Dysfunctional Root Systems
Reduced Root Spread Limited Water and Nutrient Uptake Reduced Photosynthetic Potential Reduced Energy Reserves
Problems With Dysfunctional Root Systems: Reduced Energy Reserves
Problems With Dysfunctional Root Systems: Water and Nutrient Stress
Problems With Dysfunctional Root Systems: Reduced Photosynthesis
Problems With Dysfunctional Root Systems: Reduced Stability
Photo by Eric Berg
Problems With Dysfunctional Root Systems: Reduced Stability
Photos by Kameron Kytonen
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
Diagnosing Dysfunctional Root Problems: What’s Wrong Here?
All Trees Suffered From Same Problem…
Stem Girdling Roots: a Primary Predisposing Factor
Stem Girdling Roots and Storm Failures
Photos by Eric Berg
•32% of all tree failures
•26% of all boulevard tree failures
•68% of Little-leaf Lindens in boulevards
•> 90% of trees that had SGRs had stems buried 4” or more.
Storm Damage in Minnesota: Failures due to Stem Girdling Roots (1995-2005 n=1584)
Root Collar Examinations as a Diagnostic Tool
Photo by Dave Hanson
Treatment Decisions
Photo by Dave Hanson
Treatment Decisions
Photo by Dave Hanson
Treatment Decisions
Photo by Dave Hanson
Treatment Decisions
Photos by Mark Dungan
Treatment Decisions
Photos by Mark Dungan
Treatments: 2 Years Later
Soil Line
Treatments: 8 Years Later
Treatments: 8 Years Later
8.5” SGR Removed
Treatments: 8 Years Later
Treatments: 8 Years Later
Treatments: 5 Years Later
Not All Treatments Were Successful
6 Years Post Treatment
Not All Treatments Were Successful
4 Years Post Treatment
Treatment Success often Species Dependent
30 Ohio Buckeye. 2” Caliper at Planting. Depth Correction of as Much as 9 inches.
6 Years After Planting
Prevention When Possible
Prevention When Possible
Trees Are Planted Deep to Prevent Leaning
Does it Work? No!*
2002 University of MN/Bailey Nursery Experiment
4 Tree Species, 460 Trees Total
4 Planting Depths: 0 – 2 – 4 – 6 Inches
Results? All Leaned at Same Rates
How Often Does it Happen?
881 Trees Sampled out of 5500 Total B&B and Containerized 87%: Stem Buried 2+ Inches 50%: Stem Buried 4+ Inches
*Minneapolis Park and Recreation Board; St. Paul Division of Forestry
Nursery Stock Survey 2001-2002*
Prevention When Possible
Assume That It Is Too Deep
Correcting the Problem: 1
Correcting the Problem: 2
Correcting the Problem: 3
Correcting the Problem: 3
Correcting the Problem: 4
Correcting the Problem: 5
Avoiding Other Root Problems:
Stem Girdling Root
Correcting the Problem: 5
Stem Girdling Root Removed
Correcting the Problem: 5
Correcting the Problem: 5
Stem Girdling and Encircling Roots
Correcting the Problem: 5
Correcting the Problem: 5
Correcting the Problem: 5
Removal Completed
Prevention When Possible
Photos by Stephen Schott
Problem Corrected At Planting Time
Controlling Variables: Planting Depth
Prevention When Possible
Photos by Dave Hanson
Does This Work? Probably Not.
Prevention When Possible
Photo by Dave Hanson
“Boxing” Pot-Bound Root Systems
Prevention When Possible
Photo by Dave Hanson
“Boxing” Pot-Bound Root Systems
Prevention When Possible
Photos by Gary Johnson
Alternatives to “Containers”: Root Bags
Prevention When Possible
Photos by Gary Johnson
Alternatives to “Containers”: Air Pruning Pots
Recovery of Root Systems in Gravel Beds
Recovery of Root Systems in Gravel Beds
Recovery of Root Systems in Gravel Beds
This Presentation Available by 10/26/10
www.trees.umn.edu Gary’s Notes
Woody Plant Conference