Your Landscape Mulch Will GO UP IN SMOKE! Larry G. Steward The Ohio State University ATI

BASIC FACTS ABOUT MULCH USE Mulches are commonly applied in the landscape for a variety of reasons: Mulches are commonly applied in the landscape for a variety of reasons: Aesthetic Appeal and Color Aesthetic Appeal and Color Organic Content Organic Content Nutrient Content Nutrient Content Moisture Modification Moisture Modification Temperature modification Temperature modification Reduction of Weeds Reduction of Weeds Dust and Soil Stain Abatement Dust and Soil Stain Abatement

Original Research Premise Most Commercial and Public Facilities no longer allow smoking inside Most Commercial and Public Facilities no longer allow smoking inside Only permitted location for smoking is outside 25 feet from facility entrances Only permitted location for smoking is outside 25 feet from facility entrances These facilities still desire the beauty of landscaping including organic mulching These facilities still desire the beauty of landscaping including organic mulching Consequently, is any mulching material Fire Ignition Resistant? Consequently, is any mulching material Fire Ignition Resistant?

Mulches Used 1 to 2” Pine Bark Nuggets

Mulches Used 1” Pine Bark Nuggets

Mulches Used Ground Hardwood including Bark

Mulches Used Dyed Ground Scrap Wood

Mulches Used Composted Yard Waste

Mulches Used Pine Straw

Mulches Used Oat Straw

Mulches Used Cocoa Hulls

Mulches Used Ground Cypress

Mulches Used Dyed Ground Tires

Mulches Used Brick Chips

Mulches Used Turf Grass

Three Ignition Tests Discarded burning cigarettes Discarded burning cigarettes Wooden matches Wooden matches Propane torch Propane torch

Ignition Tests Discarded Burning Cigarettes Discarded Burning Cigarettes Two times- Immediately after applying mulch and one year later Two times- Immediately after applying mulch and one year later Three cigarettes to each mulch-each a different brand Three cigarettes to each mulch-each a different brand Preliminary Findings Preliminary Findings Ignition varies to type and brand Ignition varies to type and brand Ignition varies to period of time mulch has been place Ignition varies to period of time mulch has been place

Ignition Tests Match Ignition Match Ignition One test with three wooden matches to each mulch sample One test with three wooden matches to each mulch sample Six months after mulch installed Six months after mulch installed Preliminary Findings Preliminary Findings Most all mulches will ignite with this form of ignition Most all mulches will ignite with this form of ignition Some may not continue to burn after match is extinquished Some may not continue to burn after match is extinquished

Ignition Tests Propane Torch Propane Torch Fifteen seconds applied to each mulch sample then torch removed Fifteen seconds applied to each mulch sample then torch removed Test done one year after installation of mulch Test done one year after installation of mulch Preliminary Results Preliminary Results Surprisingly even some of the organic mulches would not ignite Surprisingly even some of the organic mulches would not ignite

Ignition Results 1 Mulches and Cigarettes ( Fresh Mulch with No Old Mulch Under Mulch) Times Ignition Occurred Oat Straw 2/4 Pine Straw 1/4 Balance of mulches did not ignite

Ignition Results 2 Mulches and Cigarettes after one year (Matches had same results) Times Ignition Occurred Ground Recycled Pallets 4/4 Composted Yard Waste 4/4 Shredded Pine Bark 3/4 Oat Straw 2/4 Shredded Cypress 2/4 1” Pine Bark Nuggets 1/4 Rest of Replications 0/4

Ignition smoldered and burned down into mulch Ignition smoldered and burned down into mulch

Same Happened with Compost Same Happened with Compost

Ignition Results 3 Mulch and Propane Torch LSD = 1.19 Ease of Ignition-Torch 7.00 Decorative Ground Rubber 7.00 Pine Straw 6.88

Ignition Results Additional Match ignition of Rubber Chipped Mulch occurred every time in later demonstrations along with the Dyed Shredded Hardwood Mulch Match ignition of Rubber Chipped Mulch occurred every time in later demonstrations along with the Dyed Shredded Hardwood Mulch Fire in Chipped Rubber Mulch Fire in Chipped Rubber Mulch Gives off toxic fumes, Gives off toxic fumes, Cannot be extinguished with water in fact water spreads the flames Cannot be extinguished with water in fact water spreads the flames Extinguished by beating out with a shovel Extinguished by beating out with a shovel

Ignition Results 3 Continued Mulch—LSD=1.19 Ease Of Ignition Oat Straw 5.00 Shredded Hardwood 4.13 Shredded Cypress 4.00 Ground Recycled Pallets ” Pine Bark Nuggets ” Pine Bark Nuggets 3.13 Cocoa Shells 2.63 Composted Yard Waste 2.13

Ignition Results 3 This compared to the sod rating of 2.13 and the brick chips rating of 1.13 This compared to the sod rating of 2.13 and the brick chips rating of was equal to no flame at the end of the 15 seconds and 7 had to be extinguished after 1 minute following exposure to flame 1 was equal to no flame at the end of the 15 seconds and 7 had to be extinguished after 1 minute following exposure to flame

What Did We Prove? Water in mulch will slow ignition Water in mulch will slow ignition Age and decomposition of mulch will increase ignition probability Age and decomposition of mulch will increase ignition probability Temperature of igniter can affect ignition Temperature of igniter can affect ignition Exposure time to igniter even at lower temperatures will increase ignition Exposure time to igniter even at lower temperatures will increase ignition Certain organic mulches CAN be used near smoking locations Certain organic mulches CAN be used near smoking locations

OUR IGNITION RESULTS  OAT STRAWVERY HIGH  PINE STRAWVERY HIGH  GROUND RUBBER TIRES (DYED)VERY HIGH  SHREDDED PINE BARK, CYPRESS,  or HARDWOOD-- HIGH*  GROUND DYED PALLETSVERY HIGH*  YARD COMPOSTMEDIUM*  PINE BARK CHUNKS-TWO SIZESLOW  TURFVERY LOW  COCOA HULLSVERY LOW  BRICK CHIPSNONE

RESULTS* THE THREE NOTED WERE FOUND TO SMOLDER AND BURN WITHOUT FLAME FOR A PERIOD OF TIME WHEN AGED FOR A YEAR. THE THREE NOTED WERE FOUND TO SMOLDER AND BURN WITHOUT FLAME FOR A PERIOD OF TIME WHEN AGED FOR A YEAR. THEREFORE, IF NEW MULCH WERE COVERED OVER OLD MULCH, IGNITION OF NEW MULCH COULD OCCUR WHEN IGNITION TEMPERATURE IS REACHED. NO MATTER HOW LONG TIME HAS PASSED. THEREFORE, IF NEW MULCH WERE COVERED OVER OLD MULCH, IGNITION OF NEW MULCH COULD OCCUR WHEN IGNITION TEMPERATURE IS REACHED. NO MATTER HOW LONG TIME HAS PASSED. This NOT by spontaneous combustion This NOT by spontaneous combustion

Conclusion One In those locations where lit smoking materials are discarded, the following mulches should NOT be used: In those locations where lit smoking materials are discarded, the following mulches should NOT be used: Ground recycled pallets Ground recycled pallets Composted yard waste Composted yard waste Shredded pine bark Shredded pine bark Oat straw Oat straw Shredded cypress Shredded cypress Ground recycled tires Ground recycled tires

FLAMMABILITY OF MULCH Recent research on four common Florida mulches on flammability was done by Dr. Wayne Zipperer, et al; U. S. Forest Service, Southern Research Station, Gainesville, Florida Recent research on four common Florida mulches on flammability was done by Dr. Wayne Zipperer, et al; U. S. Forest Service, Southern Research Station, Gainesville, Florida Highest Temperatures Results were on Pine Straw and Large Pine Bark, next was Small Pine Bark and Lowest Temperature registered on Cypress Mulch Highest Temperatures Results were on Pine Straw and Large Pine Bark, next was Small Pine Bark and Lowest Temperature registered on Cypress Mulch

Conclusion Two Where there is a chance of a Firewise Landscape/Wildfire Interface, the following mulches should NOT be used: Where there is a chance of a Firewise Landscape/Wildfire Interface, the following mulches should NOT be used: Decorative ground rubber Decorative ground rubber Pine straw Pine straw Oat straw Oat straw Shredded hardwood bark Shredded hardwood bark Ground recycled pallets Ground recycled pallets

Under Decks

Around Possible “’’Ladder” Trees

Mulch and Fire  The Potential for Burning of the Mulch Needs to be a Landscaping Consideration:  When Selecting Mulch for a Public or Private Landscape  What the Environmental Conditions are for the Area—Dry or Wet  Relationship to surrounding wild areas that have potential for wildfire  Structure material in close proximity to mulch

Mulch and Fire It has not been demonstrated that Spontaneous Combustion starts Landscape Mulch Fires due to the little depth of mulch. It has not been demonstrated that Spontaneous Combustion starts Landscape Mulch Fires due to the little depth of mulch. Fires are initiated and ignited by outside sources in the landscape. Fires are initiated and ignited by outside sources in the landscape.

Possible Spontaneous Combustion Location

Landscape Mulch Depth Not enough depth to build up heat if applied properly for self ignition-”Smoke” is merely steam from moisture in mulch

Relationship to the Wildfire Interface Remember the Four Firewise Plant Zones Remember the Four Firewise Plant Zones Zone 1—Structure foundation to 5 feet Zone 1—Structure foundation to 5 feet Zone feet to 10 feet from structure Zone feet to 10 feet from structure Zone feet to 30 feet from structure Zone feet to 30 feet from structure Zone 4---Beyond 30 feet from structure(or Zone 4---Beyond 30 feet from structure(or 100 feet if uphill from wildfire source) 100 feet if uphill from wildfire source)

Helps for you in the future Eastern United States Fire Performance Plant Selector Eastern United States Fire Performance Plant Selector Beta CD available from United States Forest Service, Northeastern Area State and Private Forestry-Contact Ms. Donna Murphy Beta CD available from United States Forest Service, Northeastern Area State and Private Forestry-Contact Ms. Donna Murphy 140 trees and shrubs with Firewise ratings, use and descriptions and more 140 trees and shrubs with Firewise ratings, use and descriptions and more On Line Website On Line Website Under development now in cooperation with both Northeastern Area and Southeastern Area-USDA for release in 2009 Under development now in cooperation with both Northeastern Area and Southeastern Area-USDA for release in plants commonly found and used in Eastern U. S. 500 plants commonly found and used in Eastern U. S.

Eastern United States Fire Performance Plant Selector provides information to urban foresters and fire prevention professionals about how a specific plant species might influence the movement of fire and the safety of structures in fire-prone areas. It replaces more generalized flammability lists with an easy-to-use,It replaces more generalized flammability lists with an easy-to-use, searchable database developed using a credible, science-based ranking process. This prototype program includes 150 commonly used trees, shrubs, ground covers, vines, and grasses typically found in residential areas of the Eastern United States.This prototype program includes 150 commonly used trees, shrubs, ground covers, vines, and grasses typically found in residential areas of the Eastern United States. This tool targets users who are familiar with plant material or fireThis tool targets users who are familiar with plant material or fire prevention principles, but not both, when making decisions related to managing or planting vegetation on fire-prone sites. Users can search the database by plant name or request plantUsers can search the database by plant name or request plant recommendations based on specific needs related to fire prevention zones, plant characteristics related to flammability, or cultural preferences. From the generated lists of recommendations, users can then select a plant, and the Plant Selector generates a factsheet that summarizes the plant’s fire prevention suitability, cultural requirements, urban and utility use, and form.

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