Using Fuel Characteristics to Estimate Plant Ignitability for Fire Hazard Reduction

Abstract

There are areas in the boreal forest where the combination of highly flammable vegetation and frequent ignition events create a high fire hazard. The resultant fires cause considerable economic and social damage. During global change, fire frequency may increase in parts of the boreal forest. We are investigating the feasibility of using less-flammable vegetation to reduce the number of people-caused fires in herbaceous communities of northern Ontario. Herbaceous species abundant in these areas were ranked according to potential ignitability. Ignitability was estimated from chemical and physical fuel characteristics measured on live and dead tissue. Achillea millefolium, Aster macrophyllus and Anaphalis margaritacea had the lowest potential ignitability. Their rank was consistent for fuel characteristics measured on live and dead leaf tissue. Many of the commercially available forbs tested (e.g., Trifolium spp.) were of low to intermediate ignitability. Grass species such as Poa compressa and Agrostis scabra had the highest potential ignitability. Physical characteristics were not significantly correlated with chemical characteristics (p > 0.05, n = 20). There was a significant but trivial correlation between surface area to volume ratio and volume (r = −0.80, p ≤ 0.05, n = 20). There was a significant correlation between surface area to volume ratio and density (r = 0.54, p ≤ 0.05, n = 20). There was a significant correlation between total ash and silica-free ash content (r = 0.61, p ≤ 0.05, n = 47), between total ash and energy content (r = − 0.55, p ≤ 0.05, n = 47) and between silica free ash and energy content (r = −0.28, p ≤ 0.05, n = 47). Research is continuing to evaluate the feasibility of using less-flammable plants for fire hazard reduction. Planting less-flammable vegetation in fire prone areas, or around property and fire-sensitive natural areas, may help prevent ignition or slow fire spread. This technique could be a long term, cost effective and environmentally friendly method of fire prevention and control in selected areas of the boreal forest.