Applying herbicides to desiccate manzanita brushfields before burning

Abstract

On small plots in a greenleaf manzanita brushfield, herbicides applied as a foliar spray in May killed the small-fuel fractions of the shrubs (leaves, twigs, and small stems up to ½-inch diameter) by October, in tests near Mount Shasta, California. Late summer spraying did not kill most of the small fields until the next spring, and September sprays required 1 year to produce equal kill. On those shrub branches having dead small fuels by October, the stems, up to 2-inch diameter, dried during cold winter weather; most stems were ready for burning by early spring. Picloram, not effective as a foliar spray on manzanita, produced almost complete kill of manzanita and understory shrubs when applied as pellets on the soil surface at 8 or more pounds, a.e., per acre. A mixture of 2,4-D and 2,4,5-T, or 2,4-D alone, sprayed in May or June at 4 pounds, a.e., in 5 gallons of diesel oil per acre adequately desiccated greenleaf manzanita in small plots and on large areas. The results suggest proper timing for both the desiccation treatment and the prescribed burning to remove brush from California mountain lands.

Citation

Bentley, Jay R.; Graham, Charles A. 1976. Applying herbicides to desiccate manzanita brushfields before burning. Res. Note PSW-RN-312. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 8 p