Table 7.1: The Number of Times That Specific Mulch Types Ignited after Three Cigarettes Were Discarded on the Surface of the Mulch is Given.
Mulching Material Times Ignition Occurred
Ground recycled pallets 4
Composted yard waste 4
Shredded pine bark 3
Oat straw 2
Shredded cypress bark 2
Pine bark nuggets 1.3 to 2.5 cm 1
Decorative ground rubber 0
Pine straw (needles) 0
Shredded hardwood bark 0
Pine bark nuggets 2.5 to 5 cm 0
Cocoa shells 0
Bluegrass sod 0
Brick chips 0
Adapted from: THE EASE OF IGNITION OF 13 LANDSCAPE MULCHES by Larry G. Steward, T. Davis Sydnor, and Bert Bishop in the Journal of Arboriculture November 2003. Ignition of each mulch was attempted eight times (2 trials * 4 replicates) using lighted cigarettes.