25% off all 2020 Summer Courses
Discount applies to courses starting before September 1. Not applicable toward Legal or Paralegal Studies courses.
Coronavirus (COVID-19) Update
All summer & fall classes are offered remotely—either live-online with an instructor, entirely self-paced, or in a blended online format. Please check our coronavirus update page for our latest announcements.
Ronald Tjeerdema LinkedIn
RONALD TJEERDEMA, Ph.D., D.A.B.T., is an Associate Dean in UC Davis’ College of Agricultural and Environmental Sciences and a professor in the Department of Environmental Toxicology. He has taught for UCSC Extension since 1990.