Ages of Big Sagebrush Following Brush Control

Abstract

Six stands of big sagebrush, which had been plowed or sprayed earlier to remove brush and enhance understory vegetation, were sampled in southeastern Oregon to determine age structure of the shrubs and to evaluate rates of reinvasion. Five of the six stands contained big sagebrush older than the treatment. In three project areas plants established the first year following treatment formed the largest age class, 12 to 24% of the stand, indicating that reinvasion begins immediately after treatment. Most reestablishment occurred in the first several years after treatment for all locations. Establishment occurred either from seeds present in the soil at the time of treatment or from seeds produced as the plants became established and seed bearing. Treated sagebrush/grass ranges should remain highly productive under proper grazing use despite reinvasion of big sagebrush.