Enhancing control of eastern redcedar through individual plant ignition following prescribed burning.

Abstract

Fire-scorched crowns of live eastern redcedar (Juniperus virginiana L.) were ignited using a propane torch in 3 studies to quantify the efficacy and to determine the feasibility of the technique as a follow-up treatment for killing trees that survived prescribed burns. In the first study, we ignited 98 fire-scorched, live trees 20 to 64 days following a prescribed burn. Igniting scorched trees in several positions killed 90% of the crown and two-thirds of the trees regardless of tree size. Logistic regression models indicated reburning was more effective on trees highly damaged after prescribed burning. In the second study, one person equipped with a self-contained backpack propane burner used single-point ignition to treat in average of 1 tree every 17 seconds (range 11 to 20 seconds) on 0.25-ha plots. Effectiveness of the single-point ignition declined with increasing tree size. In the third study, the average time required to burn a tree was 19 seconds in eight 32-ha pastures. Cost in this field-scale study for labor, propane, fuel, and equipment depreciation was $0.03/ignited tree.