UC research on whole orchard recycling (WOR) has generated numerous scientific and industry publications, workshops and grower field days, and other outputs and events to extend new information to growers and other stakeholders. Explore below to see current and past events, publications, and industry magazine articles about WOR.

Featured Outreach


Webinar: Whole Orchard Recycling in Almonds and Its Effects on Orchard Productivity and Greenhouse Gas Footprints
Have you wondered what to do with all that wood after orchard removal? Have you been curious about chipping and recycling whole trees back into the orchard soil, but weren’t sure what the effects might be on your soil and the next planting?

Topics included:

  • Productivity in the next generation of almond trees
  • Nutrient management requirements
  • Effects on soil health and water holding capacity
  • Effects on disease potential
  • The potential for reducing the “carbon footprint” of an orchard


  • Dr. Amelie Gaudin, UC Davis
  • Dr. Emad Jahanzad, UC Davis
  • Dr. Brent Holtz, UCCE San Joaquin County
  • Dr. Greg Browne, USDA ARS
  • Dr. Elias Marvinney, UC Davis



Slides projected in a conference room

Scientific Publications

Jahanzad, E., Brewer, K.M., Poret‐Peterson, A.T., Culumber, C.M., Holtz, B.A., Gaudin, A.C.M. (2022) "Effects of whole-orchard recycling on nitrate leaching potential in almond production systems." J Environmental Quality. 51(5): 941-951.

Jahanzad, E., Holtz, B.A., Zuber, C.A., Doll, D., Brewer, K.M., Hogan, S., Gaudin, A.C.M. (2020) "Orchard recycling improves climate change adaptation, and mitigation potential of almond production systems." PLOS ONE.

Holtz, B., Browne, G., Doll, D., Culumber, M., Yaghmour, M., Jahanzad, E., Lampinen, B., and Gaudin, A. (2018) "Whole almond orchard recycling and the effect on second generation tree growth, yield, light interception, and soil fertility." Acta Horticulturae 1219: 265-271.

Holtz, B. (2017) "Whole-orchard recycling can sequester carbon and improve soil fertility."  Resource Magazine. 24(4): 8-11.

Holtz, B., Doll, D., and Browne, G. (2016) "Whole almond orchard recycling and the effect on second generation tree growth, soil carbon, and fertility." Acta Horticulturae 1112:127-134.

Holtz, B., Caesar-TonThat, T. (2004) “Wood chipping almond brush to reduce air pollution and its effect on soil and petiole nutrients, soil aggregation, water infiltration, and nematode and basidiomycete populations.” In: Lartey, R.T., Caesar, A.J. (Eds.), Emerging Concepts in Plant Health Management, 2004. Research Signpost, Kerala, India.

Holtz, B., McKenry, M.V., and Caesar-TonThat, T.C. (2004) "Wood chipping almond brush and its effect on the almond rhizosphere, soil aggregation and soil nutrients." Acta Horticulturae 638:315-319.


Old trees pushed over next to live green orchard

2017 Events

March 30, 2017
Kern County Almond Day, Bakersfield (100 attendees)

April 4, 2017
Developing soil health guidelines in Almond production, UC Davis (30 attendees)

June 9, 2017
Central Valley Almond Day, West Coast Nut, Fresno (200 attendees)

July 11, 2017
Nutrient Management Seminar, California Association of Pest Control Advisors (CAPCA), Lodi (50 attendees)

September 21, 2017
Fresno Madera County California Association of Pest Control Advisors (CAPCA) (250 attendees)

November 8, 2017
VII International Symposium on Almonds and Pistachios, Adelaide, South Australia (150 attendees)

November 2017
Central Valley Summit on Alternatives to Open Field Burning of Agricultural Waste, Kearney REC, Parlier (100 attendees)

December 5, 2017
Research Update: The Almond Conference, The Almond Board of California, Sacramento (400 attendees)

Orchard chipping machine

2018 Events

January 31, 2018
Butte, Glenn, Tehama Counties Almond and Walnut Day, Chico, CA (150 attendees)

February 7, 2018
Northern San Joaquin Valley Almond Day, Modesto CA (600 attendees)

May 8, 2018
What are we learning from orchard biomass (chip and mix) studies? Nickels Soil Lab Annual Field Day, Arbuckle, CA

June 20, 2018
University of California cooperative Extension, Central Valley Almond Day. “Nitrogen considerations for second generation almond trees after whole orchard recycling,” Fresno

October 17, 2018
Whole Almond Orchard Recycling Demonstration, Sponsored by the University of California Cooperative Extension, Cal Almond, Lake Springs Farm Facility, Denair, CA

October 24, 2018
Soil health and carbon sequestration potential of orchard recycling. Whole Orchard Recycling Research Review, Stockton, CA

October 30, 2018
Replanting almond and stone-fruit orchards: effective “soil health” and fertility management, California State University-Fresno, Fresno, CA

November 27, 2018
Almond Board of California Conference, Sacramento, CA

Wood chips spread on ground surface

2019 Events

January 6, 2019
Soil Science Society of America Annual Meeting, San Diego, CA

March 25, 2019
Webinar: Whole Orchard Recycling for Sustainability and Resilience of Almond Production