Apidays New York 2024 - The value of a flexible API Management solution for O...
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
39. Decline in Canopy Condition Associated with SGRs and Tilia. July 7, 2006. Tilia cordata “Greenspire”
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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
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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
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45. Condition Rating: Canopies E.g., Greenspire Littleleaf Linden to the right. Canopy condition reduced due to density.
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
59. Storm Failure Triangle Tree Condition and Defects Loading Event wind, ice, snow Site Characteristics Failure Potential Gary Johnson, University of MN
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
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65. When Roots and Stems Conflict Soil Line SGR compression point
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
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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.