Changes in streamflow in an herbicide-treated Pinyon-Juniper Watershed in Arizona


  • Malchus B. Baker Jr.


A 147-ha pinyon-juniper watershed in north-central Arizona was sprayed with a herbicide mixture to kill all overstory vegetation. After 8 years of postherbicide evaluation, the dead trees were removed. The herbicide treatment induced an increase in annual streamflow of about 157%. There is an indication that after the dead trees were removed, streamflow was reduced to near-pretreatment levels.