Mitigation of Breadfruit Orchard Establishment Challenges in Hawaiʻi: Assessing Best Practices to Address Weed Management and Ungulate Control

Project Overview

Project Type: Professional + Producer
Funds awarded in 2022: $74,998.00
Projected End Date: 12/31/2025
Host Institution Award ID: G116-23-W9211
Grant Recipient: Hawaii Ulu Cooperative
Region: Western
State: Hawaii
Principal Investigator:
Dana Shapiro
Hawaii Ulu Cooperative
Kyle Jackson
Hawai'i 'Ulu Cooperative


  • Fruits: other
  • Additional Plants: native plants, trees


  • Crop Production: agroforestry
  • Education and Training: on-farm/ranch research
  • Farm Business Management: cooperatives

    Proposal abstract:

    This project seeks to compare and assess the effectiveness of breadfruit orchard establishment practices addressing two primary challenges that Hawaiʻi farmers face: weed management and ungulate control. Together these two challenges comprise the primary cause of young tree death observed in new orchard installations, causing approximately 20% mortality rates among planted trees reported over the past five years. Four to six treatments to mitigate each challenge will be implemented and compared among five working farms planting new trees during the first two years of the project period.  In Year 3, working in partnership with the University of Hawaiʻi, results will be analyzed and best practice recommendations developed into one technical guide (PDF) and two educational videos, and disseminated through farmer networks using a combination of in-person workshops (2) and at least 100 one-on-one farm visits. The technical guide and video series will be accessible online and shared with producer organizations across Hawaiʻi and other breadfruit-growing regions. This project has great potential to improve agricultural sustainability in Hawaiʻi by reducing breadfruit tree mortality and increasing the success rate of new installations while enhancing farmers’ ability to establish and maintain food production systems using the limited resources available to them. Farmers losing young trees to pigs and intense weed competition currently constitute a significant financial loss across the state. As a result of this project, farmers will gain practical tools enabling higher tree survival rates, increased production, and strengthened economic fortitude.

    Project objectives from proposal:

      1. Through HUC’s farmer network, assess the effectiveness of six practices for sustainably managing weeds in young tree plots during new breadfruit orchard establishment or existing orchard expansion. Sustainable weed management practices to be compared were identified in collaboration with participating producers and include: mowing, cover cropping, weed mat, livestock grazing, organic herbicides, and flame burning. A two-year cohort study will be implemented on five sites around Hawai’i Island and monitored by participating growers.  
      2. Through HUC’s farmer network, assess the effectiveness of four practices for feral ungulate control during new breadfruit orchard establishment or existing orchard expansion. Sustainable ungulate control methods to be compared were identified in collaboration with participating producers and include: physical barriers constructed from wire, rubber and wood materials, and organic repellent spray. A two-year cohort study will be implemented on five sites around Hawai‘i Island and monitored by participating growers.
      3. Drawing on the empirical  results and detailed observations from the cohort study as well as follow-up interviews with participating growers, the Agricultural Professional (AP) will work in partnership with land-grant institution the University of Hawai‘i at Mānoa College of Agriculture and Human Resources (UH CTAHR) and producer representatives to develop and distribute a technical factsheet sharing best practices and recommendations for weed management and ungulate prevention during tree establishment, including information on costs and benefits of various treatment approaches. Actionable recommendations on installation and sourcing materials will be included to help farmers make practical and effective decisions. 
      4. The AP will manage and produce two educational videos from the data and analysis presented in the technical factsheet in collaboration with project partners. The purpose of these videos is to share learned methods and implementation techniques with farmers who cannot attend workshops or live in areas outside of HUC’s physical reach.
      5. Hold three in-person workshops open to HUC’s network of 100+ breadfruit producers and the broader Hawai‘i farming community. AP will organize one workshop at each of three member farm locations on three different islands during the final year of the project. 
      6. Complete at least 100 in-person, one-on-one farm visits with producers in HUC’s farmer network during the project period to disseminate project results and gather feedback from growers via surveys and structured interviews to assess project impacts. 
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.