EFFICACY AND COSTS OF CONTROLLING EASTERN REDCEDAR

Eastern redcedar (Juniperus virginiana L.) is reducing grassland produ ctivity across much of the Great Plains. Control meth-ods include broa dcast prescribed fire, herbicides, cutting, and individual tree igniti on. All methods have disadvantages when used alone. Fire can be ineffe ctive against larger trees. Intensive methods can be too expensive for low-productivity grasslands. The objectives of this research were to determine the effects of broadcast prescribed fire alone as measured a t 3 weeks after fire; to compare the effects of picloram herbicide app lication with or without fire, sawing with or without fire, and indivi dual tree ignition with fire; and to compare all treatment costs. Trea tments were applied at a central Nebraska rangeland site in 1993 and 1 994. Fire mortality was 77% in 1993 and 67% in 1994. Either picloram o r cutting after fire provided nearly 100% control of trees < 3 m tall, but cutting was more effective for trees > 3 m tall. Total mortality due to treatment combinations generally was higher in 1993, when burni ng conditions were more favorable. Burning, at an estimated cost of $4 .96 ha(-1), before picloram application or cutting reduced total costs by nearly half. Picloram application costs were reduced from $90.10 h a(-1) to $47.95 ha(-1), and cutting costs from $62.92 ha(-1) to 39.26 ha(-1) Burning first also reduced cutting time from 362 min ha(-1) to 184 min ha(-1), but did not significantly decrease picloram applicatio n time. Prescribed fire should precede intensive treatment application s if possible, both to reduce costs and improve total effectiveness. B ecause the costs and effectiveness of burning followed by either piclo ram or cutting are similar, managers should choose the method most sui table to individual circumstances.