Unri Deep Roots Webcast 08 Compressed
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The document discusses research on dysfunctional root systems and their impact on the lifespan of trees in urban and landscape settings. It finds that trees with abnormal or pot-bound root systems are more likely to experience issues like stem girdling roots, reduced ability to compartmentalize damage, and premature death. Studies show trees with soil over their roots more than 1-3 inches thick are also more prone to problems and storm damage failure due to stem girdling roots. Correcting pot-bound root systems through techniques like slicing or boxing can help reduce these risks.
![University of Minnesota Urban Forestry and Horticulture Institute Chad Giblin, Research Scientist Jeff Gillman, Associate Professor Dave Hanson, Research Specialist Gary Johnson, Professor and corresponding presenter. [email_address] , 612-625-3765. Rebecca Koetter, Research Fellow Patrick Weicherding, Ext. Educator and Professor](https://image.slidesharecdn.com/unrideeprootswebcast08compressed-090421121256-phpapp02/85/Unri-Deep-Roots-Webcast-08-Compressed-2-320.jpg)
Unri Deep Roots Webcast 08 Compressed
- 1. DEEP ROOTS RESEARCH UNRI Webcast – 08/13/08 “ Dysfunctional Root Systems and Brief Landscape Lives” Gary Johnson, Department of Forest Resources, University of Minnesota
- 2. University of Minnesota Urban Forestry and Horticulture Institute Chad Giblin, Research Scientist Jeff Gillman, Associate Professor Dave Hanson, Research Specialist Gary Johnson, Professor and corresponding presenter. [email_address] , 612-625-3765. Rebecca Koetter, Research Fellow Patrick Weicherding, Ext. Educator and Professor
- 3. University of Minnesota Urban Forestry and Horticulture Institute
- 4. 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. ***Kielbaso, 1989
- 5. State of the Urban Forest – 1989 J.J. Kielbaso 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.
- 10. What’s a “Normal” Root System? 5 month root system from seed (butternut)
- 11. 6 year sugar maple root system from seed
- 12. Approximately 20 year old root system of linden
- 13. White spruce root system Pat Bartlett – Bartlett Forestry
- 14. What are “Normal” Roots? Seed Propagated Roots
- 15. “ Normal” Roots: Adventitious Roots
- 16. Abnormal Root Systems Root systems that deviate from normal or average root systems.
- 19. Plug Trays
- 20. J-Roots
- 23. Dysfunctional Root Systems Roots in unhealthy interactions within a plant system.
- 24. Dysfunctional Root Systems Buried root system growing to surface
- 25. Dysfunctional Root Systems Stem Encircling Roots
- 26. Dysfunctional Root Systems Stem Girdling Roots
- 27. Dysfunctional Root Systems Stem Girdling Roots and Stem Girdling Suckers
- 28. Dysfunctional Root Systems Pot-Bound Root System
- 29. Effects on Landscape Lives Predisposition to other problems Stunted growth Premature death/failure Reduced ability to compartmentalize
- 30. A Survey of Practitioners : North American Members of ISA (1998, n = 282) Regarding Stem Girdling Roots and Tree Loss, Practitioners Stated: Relationship to tree decline and death - 82% of the time. Relationship to the sudden failure of trees – 18% of the time
- 34. Reduced Ability to Compartmentalize
- 35. Premature Death
- 36. Premature Failure in Loading Events
- 37. Three “Deep Root” Studies Frequency of Buried Root Systems. Stem Girdling Roots & Storm Failures. Correcting Pot-Bound Root Systems.
- 38. Frequency of Buried Root Systems in the Landscape
- 39. Decline in Canopy Condition Associated with SGRs and Tilia. July 7, 2006. Tilia cordata “Greenspire”
- 40. Depth of Soil Over Tree Roots: A Survey of 5 Landscape Species Range of Soil Depths over Roots Condition of Canopies and Stems Frequency, Extent, Location and Impact of Encircling or Stem Girdling Roots
- 41. Depth of Soil over Roots Surveys: Sites and Selection Minneapolis 1997 - Acer saccharum , 1999 - Fraxinus pennsylvanica , 1999 - Tilia cordata , Rochester 2001 - Celtis occidentalis , Saint Paul 2004 - Gleditsia triacanthos N = 100 (+/-)Per Species, Randomly Selected
- 42. Depth of Soil Over Roots: Survey Protocol 3-9” d.b.h. Trees Surveys included two teams. 1 st Team “blind” condition rated canopies and stems 0-4 Rating System
- 43. Criteria for Condition Rating Trees: Canopy and Stem Conditions ~ 10% cambial loss. One crack and/or one seam. 3.0 ~ 10-25% Dieback, or Loss of Density, or <50% L.C.R., or Loss of Symmetry. No cambial loss*. No decay. No cracks/seams. 4.0 No Dieback. Characteristic Density for the species. 60%+ Live Crown Ratio (L.C.R.). Symmetrical. Stem Pts Canopy
- 44. Condition Rating: Canopies 0-4 Rating System: 0 = Dead 4 = No obvious defects. Canopy condition rating factors: Characteristic density for the Species, Live crown ratio (60% standard), Crown symmetry, Dieback.
- 45. Condition Rating: Canopies E.g., Greenspire Littleleaf Linden to the right. Canopy condition reduced due to density.
- 46. Condition Rating: Stems Factors : Lost Bark/Living Cambium, Cracks/Ribs, Decay, Contributing Agents. Stem Girdling Roots (above ground) 0-4 Rating System: 0 = No living cambium in stem, 4 = No obvious defects.
- 47. Condition Rating: Stems Dead Cambium Frost Crack
- 48. Depth of Soil over Roots Surveys: Root Collar Exams 2 nd Team performed root collar examination: Data Recorded : Depth to first order roots, Frequency and location of Stem Encircling Roots (SERs) and Stem Girdling Roots (SGRs), % of stem affected.
- 49. Depth of Soil over Roots Surveys: Root Collar Exam Protocol Typical tools for root depth evaluations: Surveyor’s arrow Hand tools Wet/Dry vac Air knife
- 50. Summaries Majority Had > 1” Soil Over Roots* Tilia, Acer and Fraxinus Worst: > 90% w/4”+ 1”+ Soil = More SER’s Most Vulnerable Species: Tilia, Celtis, Fraxinus Worst Condition Rating:Soil Depth – Tilia, Acer, Fraxinus Most Common SGR’s:Soil Depth – Tilia, Fraxinus, Celtis, Acer
- 51. What IS Too Deep? Frequency of Stem Encircling Roots: 1-3 Inches* Frequency of Stem Girdling Suckers: 5 Inches** Frequency of Stem Girdling Roots: 1-3 Inches* *Sugar Maple, Green Ash, Littleleaf Linden, Hackberry, Honeylocust **Littleleaf Linden
- 52. What IS Too Deep? Negative Effects on Health? Species Dependent. 1-3.5 inches was Too Deep. Johnson and Johnson, 1997 Johnson and Borst, 1999 Johnson and Hauer, 2000 Johnson, et al., 2006. Planting Depth Interim Report.
- 53. Where it Began?: Containerized Depth Problems
- 54. Too Deep? Assume That It Is
- 55. 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*
- 56. Why Does it Happen? To Stabilize Trees in Containers.
- 57. 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
- 58. Storm Failure Research: Most common pre-existing conditions
- 59. Storm Failure Triangle Tree Condition and Defects Loading Event wind, ice, snow Site Characteristics Failure Potential Gary Johnson, University of MN
- 60. Storm Failure: pre-existing conditions
- 61. Storm Failure: pre-existing condition
- 62. Premature Failure in Loading Events* III. Most common pre-existing conditions : For all damage, separating preexisting conditions : CONDITION % OF TOTAL Decay Only 13 Stem Girdling Roots (SGR) 12 Included Bark Only 4 Root Problems (other than SGR) 3 Codominant Leaders Only 4 Construction Damage Only 1 *Storm Damage 1995-2005; University of Minnesota
- 63. Storm Damage in Minnesota: 1995-2005 n=1584 Total Failures (Trees failed at or below ground line) Was Most Common Damage Category = 54% of all damage, The presence of SGRs was the most common pre-existing condition (32%).
- 64. What IS Too Deep? Impact On Storm Damage to Trees? Most common reason for total failure: Buried SGRs. Species dependent. 1-4 inches. Johnson, 2006. “Storm Damage in Minnesota, 1995-2005.”
- 65. When Roots and Stems Conflict Soil Line SGR compression point
- 66. Layers of Stem Girdling Roots: Tilia
- 67. Soil Line SGR Compression
- 68. Storm Damage in Minnesota: SGRs below ground with compression Norway Maple ( Acer platanoides )
- 69. Storm Damage in Minnesota: 1998 n=564 1995-2005 n=1584 Total Tree Failures In Boulevards Most Commonly Damaged Size (d.b.h.) ranges 1998 1995-2005 Size (d.b.h.) Range % of Total % of Total 6-10 inches 28.6 29.0 >25 inches 25.7 26.0 20-25 inches 15.7 16.0 10-15 inches 14.3 14.0 15-20 inches 14.3 14.0
- 70. Storm Damage in Minnesota: Failures due to Stem Girdling Roots 1995-2005 n=1584 32% of all tree failures , located on the edges of storms 26% of all boulevard total tree failures (53% of 6-10” category) 68% of Little-leaf Lindens that failed in boulevards (#3 rd most common species) > 90% of trees that had SGRs had stems buried 4” or more.
- 71. Storm Damage in Minnesota: 1998 n=564 1995-2005 n=1584 Commonly Damaged Species with Chronic Problems 1998 1995-2005 Little Leaf Lindens: 73% of all 76% that failed were 4”+ deep and had stem girdling roots causing stem compression. These trees failed below the stem compression points.
- 72. Decline in Stem Condition Associated with SGR’s and Tilia
- 73. Stem Girdling Suckers! University of Minnesota Planting Depth Study 2000-2007 Lindens at 5” depth = Higher Frequency of Suckering. Higher Frequency of Suckering = Stem Girdling Suckers and Higher Mortality Rate
- 77. Correcting Pot-Bound Root Systems Study One: 14 month experiment. 2 species (Tilia and Salix). 3 Treatments (slice, butterfly and “tease”). No statistical differences between treatments and controls on survival (100%) and root production. Arboriculture & Urban Forestry, Volume 33, Issue 1, January 2007.
- 78. Correcting Pot-Bound Root Systems Study Two: Five years. Four species: Acer platanoides, Acer x freemanii, Thuja occidentalis, Malus sp. Two treatments: slicing, “boxing.” Data: survival, condition ratings, caliper increase, root production.
- 79. Correcting Pot-Bound Root Systems Complete randomized block design. Control and 2 treatments. 8 replicates. 11-05 to 11-10 study.
- 80. Correcting Pot-Bound Root Systems “ Boxing” Control Scoring
- 81. Correcting Pot-Bound Root Systems Results to Date (08-08-08): Mortality Rates: Controls:0; Slice Treatment:0; Boxing Treatment:0. Condition Rating: No significant differences. Growth Rates: No significant differences.
- 82. Other Research? Douglas Airhart – Tennessee Tech U. Bonnie Appleton – VA Tech. Mike Arnold – Texas A & M Susan Day – VPI Donna Fare – U. S. National Arboretum Ed Gilman – U of Florida Christina Wells – Clemson University
- 83. Other Research? J. Roger Harris, VPI Gary Watson, Morton Arboretum David Williams and Gary Kling, U of IL T. Davis Sydnor and Richard Rathjens, Ohio State University
- 84. Other Research?