On large plots cleared in 1961 at three California mountain locations, different herbicide treatments were applied once, twice, or three times in consecutive years, beginning in 1962. Results were evaluated in 1965. A single spray was unsatisfactory; only the initial seedlings and weaker sprouting plants were killed, and many new seedlings became established in 1963 and 1964. Two consecutive sprays greatly reduced brush competition, but many of the vigorous sprouts survived along with numerous new seedlings. Three sprays killed almost all of the most resistant plants; only very thin brush stands of low vigor survived. Broadcast sprays were more effective than hand applications in killing dense stands of seedlings. Either 2,4-D or 2,4,5-T, or a mixture of the two, was effective in repeated applications at 3 to 4 pounds, a.e., per acre. Dosages of 2 pounds generally were ineffective; 8 pounds was excessive. Test results were successfully applied in helicopter sprays in subsequent years.