Balancing Roadside Tree Benefits and Risk of Streetscape Tree Crashes

Summary: An article in Arboriculture & Urban Forestry March 2019 assesses balancing benefits of roadside trees against risk of streetscape tree crashes.

an extreme example of a streetscape tree crash: BBC News (UK) @BBCNews, via Twitter Dec. 16, 2018

An article in Arboriculture & Urban Forestry March 2019 associates the risk of streetscape tree crashes with the "probability of an event occurring and the consequence of the event should it occur."

Co-authors Ethan Allen, George Fitzpatrick, Andrew Koeser, Michael Olexa and Jeffery Van Treese II broach appealing, pleasing, stress-reducing, value-added tree-lined roadsides when target-struck by tree failure. Streetscape trees correlate socio-economically with output state expenditure and value-added capital consumption, income, indirect business tax and wage impacts and with fixed-object crashes in run-off-road accidents. Roadway conditions, design and geometry and vehicle weight determine the relative risk of streetscape tree crashes, whether roadside trees dispense hazardous tree failures or roadway definitions.

Guardrail leading ends, streetscape trees and utility poles enhance probabilities of fatal injuries in fixed-object crashes even as constrained, enclosed, smaller streetscapes encourage less risky driving.

Fixed-object crash severity fetches no injuries; minor bruises, lacerations and scrapes; major disabilities and incapacitations, including fractures and severed limbs; or fatal injuries within 30 days.

The article Frequency and Severity of Tree and Other Fixed Object Crashes in Florida, 2006-2013, gauged streetscape tree crashes at 14.6 percent of 323,581 single-vehicle crashes. Rural and urban settings respectively harbored streetscape tree crashes as the second and third commonest crash types, as 15 and 14.2 percent of their crashes, 2006-2013. Predictor variables of daylight, dark, dark with lighting and dawn/dusk identified streetscape tree crashes as respectively 10, 8.2, 23.1 and 9.8 percent of 323,581 single-vehicle crashes.

Streetscape tree crashes juggled respective frequencies of 14.29, 9.48, 6.8, 4.48 and 3.73 percent in single-vehicle crashes in severe crosswind, low-visibility, clear, rainy and cloudy weathers.

Severity analysis by no, minor, severe and fatal injuries knew respective frequencies of 46.6, 40.8, 10.8 and 1.7 percent of 7,341 total streetscape tree crashes, 2006-2013.

Of barrier, ditch, fence, no-fixed-object, pole, rollover, sign, structure, tree and water single-vehicle crashes, signs and structures logged far less severe levels than streetscape tree crashes. Rollovers manifest likelihoods of increased severity levels 1.5 times that of streetscape tree crashes and model 6.1 and 14.72 percent of rural and urban single-vehicle crashes. Narrow clear zones and lane widths on high-speed rural and low-speed urban roadways and large-zoned, wide-laned urban roadways net respectively high-frequency and low-frequency streetscape tree crashes.

Planters, trees and low-speed wide lanes respectively occasion fewer mid-block and urban run-off-roadway, greater rural run-off-roadway and, with increased driveway and pole density, greater single-vehicle crashes.

Streetscape tree crashes presented 1.5 and 3.5 percent of 3,033,048 crashes and of road fatalities recorded by the Florida Department of Highway Safety and Motor Vehicles.

The eight-year period queued up 94 yearly deaths in tree-related crashes and 15,464,241 licensed Florida drivers, for a 1:164,513 risk of harm in streetscape tree crashes. The National Safety Council and the Quantitative Tree Risk Assessment reveal respective risks at 1:9,008 and 1:1,000,000 for all United States motor vehicles and in arboriculture. National Safety Council statistics show 17-year spikes by 6,113 and 15,080 in deaths from respiratory and cardiovascular illnesses where excessive tree removal signifies lost tree canopies.

One Florida Atlantic University and four University of Florida researchers tether risk of streetscape tree crashes versus benefit to removing high-risk, low-value, not low-risk, high-value, trees.

A streetscape tree crash damages both the tree and the vehicle; Karrinyup Road, Stirling, West Australia, western Australia; Tuesday, March 27, 2012, 15:09:31: perthhdproductions, CC BY 2.0 Generic, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

an extreme example of a streetscape tree crash: BBC News (UK) @BBCNews, via Twitter Dec. 16, 2018, @ https://twitter.com/BBCNews/status/1074263371007037440

A streetscape tree crash damages both the tree and the vehicle; Karrinyup Road, Stirling, West Australia, western Australia; Tuesday, March 27, 2012, 15:09:31: perthhdproductions, CC BY 2.0 Generic, via Flickr @ https://www.flickr.com/photos/perthhdproductions/7471223692/

For further information:

BBC News (UK) @BBCNews 16 December 2018. "Shrewsbury crash leaves car vertical in tree." Twitter.
Available @ https://twitter.com/BBCNews/status/1074263371007037440

Gilman, Ed. 2011. An Illustrated Guide to Pruning. Third Edition. Boston MA: Cengage.

Hayes, Ed. 2001. Evaluating Tree Defects. Revised, Special Edition. Rochester MN: Safe Trees.

Injury Facts. 2017 Edition. Itasca IL: National Safety Council.

Marriner, Derdriu. 17 February 2019. “Plant Appraisal Estimate, Scope, Data, Analysis, Reconciliation, Report.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2019/02/plant-appraisal-estimate-scope-data.html

Marriner, Derdriu. 27 January 2019. “Urban Tree Vulnerability in Residential Toronto, Ontario, Canada.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2019/01/urban-tree-vulnerability-in-residential.html

Marriner, Derdriu. 30 December 2018. "Plant Appraisal: Cost and Value Estimates and Economic Principles." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/12/plant-appraisal-cost-and-value.html

Marriner, Derdriu. 23 December 2018. "Six-Year Forest Health Ambassador Program of Oakville, Ontario, Canada." Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2018/12/six-year-forest-health-ambassador.html

Marriner, Derdriu. 21 October 2018. "Nursery Production Systems: Tough Urban Landscape Trees on Rough Sites." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/10/nursery-production-systems-tough-urban.html

Marriner, Derdriu. 16 September 2018. "Induced-Resistance Agents, Silicon Fertilizers, Synthetic Fungicides." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/09/induced-resistance-agents-silicon.html

Marriner, Derdriu. 26 August 2018. "Nursery Production Systems for Successful Urban Tree Plantings." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/08/nursery-production-systems-for.html

Marriner, Derdriu. 29 July 2018. "Tree Roots Branch in Fabric Containers But Circle and Girdle Plastic." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/07/tree-roots-branch-in-fabric-containers.html

Marriner, Derdriu. 30 June 2018. "Wood Decay Fungi Management of Terminal Urban Pathogens." Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2018/06/wood-decay-fungi-management-of-terminal.html

Marriner, Derdriu. 27 May 2018. "Downtown Commercial Streetscape Tree Populations in Toronto, Canada." Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/05/downtown-commercial-streetscape-tree.html

Marriner, Derdriu. 28 April 2018. “Mushroom-Forming and Non-Mushroom-Forming Fungal Life Cycle Traits.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2018/04/mushroom-forming-and-non-mushroom.html

Marriner, Derdriu. 17 March 2018. “Emerald Ash Borer Rapid Response Community Preparedness Project.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2018/03/emerald-ash-borer-rapid-response.html

Marriner, Derdriu. 17 February 2018. “Tree Retention by Arborists for Wildlife Habitat Friendly Tree Care.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2018/02/tree-retention-by-arborists-for.html

Marriner, Derdriu. 14 January 2018. “Integrated Vegetation Management Study in North and South Yukon, Canada.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2018/01/integrated-vegetation-management-study.html

Marriner, Derdriu. 9 December 2017. “Tree Inventories: Preemptive and Proactive or Piecemeal and Reactive.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/12/tree-inventories-preemptive-and.html

Marriner, Derdriu. 25 November 2017. “Chlorantraniliprole Reduced-Risk Insecticides Get Leaf-Eaters Not Bees.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/11/chlorantraniliprole-reduced-risk.html

Marriner, Derdriu. 28 October 2017. “Palm Plant Health Care: Abiotic, Biotic Stress Culture and Management.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/10/palm-plant-health-care-abiotic-biotic.html

Marriner, Derdriu. 16 September 2017. “Predawn Leaf Water Potentials Indicate Crown Dieback and Water Status.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/09/predawn-leaf-water-potentials-indicate.html

Marriner, Derdriu. 19 August 2017. “Palm Tree Identification and Pruning of Native and Naturalizable Palms.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/08/palm-tree-identification-and-pruning-of.html

Marriner, Derdriu. 22 July 2017. “Commonly Planted, Potentially Phytoremediating Street Tree Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/07/commonly-planted-potentially.html

Marriner, Derdriu. 17 June 2017. “Root Loss From Root Pruning and Root Shaving of Stem-Girdling Roots.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/06/root-loss-from-root-pruning-and-root.html

Marriner, Derdriu. 27 May 2017. “Age and Canopy Area Cost Less and Tell More in Urban Tree Inventories.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/05/age-and-canopy-area-cost-less-and-tell.html

Marriner, Derdriu. 22 April 2017. “Urban Root Management: Big Infrastructure, Small Space, Stressed Roots.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/04/urban-root-management-big.html

Marriner, Derdriu. 12 March 2017. “Flexural Elasticity Modulus: Trees and Watersprouts Bend or Break.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2017/03/flexural-elasticity-modulus-trees-and.html

Marriner, Derdriu. 18 February 2017. “Plant Health Care Diagnostics When Plants and Places Wrong One Another.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/02/plant-health-care-diagnostics-when.html

Marriner, Derdriu. 14 January 2017. “Tree Fertilization for Fine Root Growth and Whole Root System Effects.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2017/01/tree-fertilization-for-fine-root-growth.html

Marriner, Derdriu. 17 December 2016. “Abiotic and Biotic Stress in Low Maintenance Tree Health Care Programs.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/12/abiotic-and-biotic-stress-in-low.html

Marriner, Derdriu. 19 November 2016. “Organic Amendments to Compacted Degraded Urban Highway Roadsides.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/11/organic-amendments-to-compacted.html

Marriner, Derdriu. 15 October 2016. “Tree Protection Zones by Arborists for All Construction Project Phases.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/10/tree-protection-zones-by-arborists-for.html

Marriner, Derdriu. 17 September 2016. “Stormwater Runoff Landscaping With Urban Canopy Cover and Groundcover.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/09/stormwater-runoff-landscaping-with.html

Marriner, Derdriu. 13 August 2016. “Changing Places: Tree Nutrient Movement Down, Tree Water Movement Up.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/08/changing-places-tree-nutrient-movement.html

Marriner, Derdriu. 16 July 2016. “Treated or Untreated Oriental Bittersweet Vine Management Cut-Stumping.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/07/treated-or-untreated-oriental.html

Marriner, Derdriu. 18 June 2016. “Tree Injection Site Procedures: Manufacturer's Instructions and Labels.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/06/tree-injection-site-procedures.html

Marriner, Derdriu. 22 May 2016. “Electrical Utility Area Temperate Urban Street Trees: Pruned Regrowth.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/05/electrical-utility-area-temperate-urban.html

Marriner, Derdriu. 16 April 2016. “Tree Injection Methods: Treatment Option in Integrated Pest Management.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/04/tree-injection-methods-treatment-option.html

Marriner, Derdriu. 6 March 2016. “Bare-Rooted Ornamental Urban Transplants: Amendments Against Mortality.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/03/bare-rooted-ornamental-urban.html

Marriner, Derdriu. 28 February 2016. “Bark Protective Survival Mechanisms Foil Deprivation, Injury, Invasion.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2016/02/bark-protective-survival-mechanisms.html

Marriner, Derdriu. 23 January 2016. "LITA Model: Linear Index of Tree Appraisal of Large Urban Swedish Trees." Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2016/01/lita-model-linear-index-of-tree.html

Marriner, Derdriu. 19 December 2015. “Tree Lightning Protection Systems: Site, Soil, Species True Designs.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/12/tree-lightning-protection-systems-site.html

Marriner, Derdriu. 24 October 2015. “Tree Lightning Protection Systems Tailored to Sites, Soils, Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/10/tree-lightning-protection-systems.html

Marriner, Derdriu. 15 August 2015. “Tree Friendly Urban Soil Management: Amend, Fertilize, Mulch, Till!” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/08/tree-friendly-urban-soil-management.html

Marriner, Derdriu. 13 June 2015. “Tree Friendly Urban Soil Management: Assemble, Assess, Assist, Astound.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/06/tree-friendly-urban-soil-management.html

Marriner, Derdriu. 18 April 2015. “Tree Wound Responses: Healthy Wound Closures by Callus and Woundwood.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2015/04/tree-wound-responses-healthy-wound.html

Marriner, Derdriu. 15 February 2015. “Urban Forest Maintenance and Non-Maintenance Costs and Benefits.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2015/02/urban-forest-maintenance-and-non.html

Marriner, Derdriu. 13 December 2014. “Tree Dwelling Symbionts: Dodder, Lichen, Mistletoe, Moss and Woe-Vine.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/12/tree-dwelling-symbionts-dodder-lichen.html

Marriner, Derdriu. 18 October 2014. “Tree Cable Installation Systems Lessen Target Impact From Tree Failure.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/10/tree-cable-installation-systems-lessen.html

Marriner, Derdriu. 16 August 2014. “Flood Tolerant Trees in Worst-Case Floodplain and Urbanized Scenarios.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/08/flood-tolerant-trees-in-worst-case.html

Marriner, Derdriu. 14 June 2014. “Integrated Vegetation Management of Plants in Utility Rights-of-Way.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/06/integrated-vegetation-management-of.html

Marriner, Derdriu. 12 April 2014. “Tree Twig Identification: Buds, Bundle Scars, Leaf Drops, Leaf Scars.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/04/tree-twig-identification-buds-bundle.html

Marriner, Derdriu. 15 February 2014. “Tree Twig Anatomy: Ecosystem Stress, Growth Rates, Winter Identification.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2014/02/tree-twig-anatomy-ecosystem-stress.html

Marriner, Derdriu. 14 December 2013. “Community and Tree Safety Awareness During Line- and Road-Clearances.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/12/community-and-tree-safety-awareness.html

Marriner, Derdriu. 13 October 2013. “Chain-Saw Gear and Tree Work Related Personal Protective Equipment.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2013/10/chain-saw-gear-and-tree-work-related.html

Marriner, Derdriu. 12 October 2013. “Storm Damaged Tree Clearances: Matched Teamwork of People to Equipment.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/10/storm-damaged-tree-clearances-matched.html

Marriner, Derdriu. 17 August 2013. “Storm Induced Tree Damage Assessments: Pre-Storm Planned Preparedness.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/08/storm-induced-tree-damage-assessments.html

Marriner, Derdriu. 15 June 2013. “Storm Induced Tree Failures From Heavy Tree Weights and Weather Loads.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/06/storm-induced-tree-failures-from-heavy.html

Marriner, Derdriu. 13 April 2013. “Urban Tree Root Management Concerns: Defects, Digs, Dirt, Disturbance.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/04/urban-tree-root-management-concerns.html

Marriner, Derdriu. 16 February 2013. “Tree Friendly Beneficial Soil Microbes: Inoculations and Occurrences.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2013/02/tree-friendly-beneficial-soil-microbes.html

Marriner, Derdriu. 15 December 2012. “Healthy Urban Tree Root Crown Balances: Soil Properties, Soil Volumes.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/12/healthy-urban-tree-root-crown-balances.html

Marriner, Derdriu. 13 October 2012. “Tree Adaptive Growth: Tree Risk Assessment of Tree Failure, Tree Strength.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/10/tree-adaptive-growth-tree-risk.html

Marriner, Derdriu. 11 August 2012. “Tree Risk Assessment Mitigation Reports: Tree Removal, Tree Retention?” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/08/tree-risk-assessment-mitigation-reports.html

Marriner, Derdriu. 16 June 2012. “Internally Stressed, Response Growing, Wind Loaded Tree Strength.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/06/internally-stressed-response-growing.html

Marriner, Derdriu. 14 April 2012. “Three Tree Risk Assessment Levels: Limited Visual, Basic and Advanced.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/04/three-tree-risk-assessment-levels.html

Marriner, Derdriu. 19 February 2012. “Qualitative Tree Risk Assessment: Risk Ratings for Targets and Trees.” Earth and Space News. Sunday.
Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment-risk.html

Marriner, Derdriu. 18 February 2012. “Qualitative Tree Risk Assessment: Falling Trees Impacting Targets.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2012/02/qualitative-tree-risk-assessment.html

Marriner, Derdriu. 10 December 2011. “Tree Risk Assessment: Tree Failures From Defects and From Wind Loads.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/12/tree-risk-assessment-tree-failures-from.html

Marriner, Derdriu. 15 October 2011. “Five Tree Felling Plan Steps for Successful Removals and Worker Safety.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/10/five-tree-felling-plan-steps-for.html

Marriner, Derdriu. 13 August 2011. “Natives and Non-Natives as Successfully Urbanized Plant Species.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/08/natives-and-non-natives-as-successfully.html

Marriner, Derdriu. 11 June 2011. “Tree Ring Patterns for Ecosystem Ages, Dates, Health and Stress.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/06/tree-ring-patterns-for-ecosystem-ages.html

Marriner, Derdriu. 9 April 2011. “Benignly Ugly Tree Disorders: Oak Galls, Powdery Mildew, Sooty Mold, Tar Spot.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/04/benignly-ugly-tree-disorders-oak-galls.html

Marriner, Derdriu. 12 February 2011. “Tree Load Can Turn Tree Health Into Tree Failure or Tree Fatigue.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2011/02/tree-load-can-turn-tree-health-into.html

Marriner, Derdriu. 22 December 2010. “Tree Electrical Safety Knowledge, Precautions, Risks and Standards.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2010/12/tree-electrical-safety-knowledge.html

Van Treese II, Jeffery W.; Andrew K. Koeser; George E. Fitzpatrick; Michael T. Olexa; and Ethan J. Allen. March 2019. "Frequency and Severity of Tree and Other Fixed Object Crashes in Florida, 2006-2013." Arboriculture & Urban Forestry 45(2): 65-74.