The use of nearly all control methods may be restricted under specific conditions, such as physical accessibility to infested areas, phenology of the plant, sensitivity of surrounding vegetation or region, and restricted use or limited availability of herbicides. Historically, fire played an important role in the maintenance of native grasslands and under appropriate controlled conditions can serve as an effective weed control technique. Furthermore, this method has the added benefit of stabilizing the ecosystem by restoring native plant diversity to these infested sites in California grasslands. Hexazinone has become widely used for vegetation management in conifer site preparation following catastrophic fire. At each fire location, hexazinone treatments were compared to untreated areas, both burned and unburned.
Results indicate that hexazinone treatment doubled the stem height and diameter in each burn site.
The inhibition in conifer survival and growth was correlated to an increase in shrub cover and a reduction in light penetration. Additional studies indicated that after 8 years, native species richness was highest in both the unburned area and the hexazinone treated site, but was lowest in the untreated area. Results of this investigation demonstrate that hexazinone site preparation can lead to the economic establishment of a coniferous forest without jeopardizing long-term native plant biodiversity. Despite an initial reduction in plant diversity in hexazinone treated areas, the native plant flora soon recovered to levels similar to that of an adjacent unburned and untreated forest. Outreach My extension work focuses on providing both oral and written information on the biology, ecology and control of weeds in non-crop environments, with emphasis on California.