Final report for OW22-374
Project Information
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. Several 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.
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- Through HUC’s farmer network of over 100 farmers, assess the effectiveness of several 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, weed mat, and the use of mulch. A two-year cohort study will be implemented on five sites around Hawai’i Island and monitored by participating growers.
- Through HUC’s farmer network, assess the effectiveness of several 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. A two-year cohort study will be implemented on five sites around Hawai‘i Island and monitored by participating growers.
- 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.
- 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.
- 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.
- 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.
The proposed research and education objectives will be completed within the scope of the three-year timeline provided in the Project Tracker Table below:
Project Tracker Start Date: 04/02/2022 End Date: 12/31/2025 *NCE approved by WSARE staff - details below
Site visit 6 and 7 were mistakenly copied in to the schedule but were after the trial end date. Final site visits will occur at the end of the trial period in the first week of May 2025.
|
Position |
Start Date |
End Date |
Milestone/Activity |
|
1 |
4/2/2022 |
5/1/2022 |
Site Planning Meeting w/ Farmer Cohort *Complete |
|
2 |
5/2/2023 |
5/2/2025 |
Research Observation Period: Ungulate Control * In progress |
|
3 |
5/2/2023 |
5/2/2025 |
Research Observation Period: Weed Management *In progress |
|
5 |
5/5/2023 |
5/28/2023 |
Site Visit 1 * Complete |
|
6 |
10/1/2023 |
10/31/2023 |
Site Visit 2 * Complete |
|
7 |
5/5/2024 |
5/28/2024 |
Site Visit 3 * Complete |
|
8 |
10/1/2024 |
10/31/2024 |
Site Visit 4 * Complete |
|
9 |
5/3/2025 |
7/1/2025 |
Develop and Design Technical Fact Sheet: Due July 1, 2025 |
|
10 |
5/3/2025 |
7/31/2025 |
Ungulate Control Video Development: Due July 31, 2025 |
|
11 |
5/3/2025 |
8/31/2025 |
Weed Management Video Development: Due August 31, 2025 |
|
12 |
9/1/2025 |
9/29/2025 |
Workshop 1: Announcement and Execution |
|
13 |
10/1/2025 |
10/31/2025 |
Workshop 2: Announcement and Execution |
|
14 |
11/1/2025 |
11/30/2025 |
Workshop 3: Announcement and Execution |
|
15 |
12/1/2025 |
12/31/2025 |
Project Evaluation and Assessment + Reporting |
Cooperators
- - Producer
- - Technical Advisor
- - Producer
- - Producer
- - Producer
- - Producer
Research
The proposed project is guided by two overarching research objectives, stated below along with specific methods and materials used to accomplish each objective. Progress updates are included to reflect installation of trials in the field and current status of each trial site, treatment numbers and adjustments in the work plan due to selecting best methods on a site-specific basis depending on acreage, available equipment, and environmental conditions as well as the preferences of the individual producers.
Research Objective #1) Through HUC’s farmer network, assess the effectiveness of three 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, mulching, and the use of weed mat. The number of treatments was reduced to three types in order to accommodate producer needs, available equipment and acreage, and consolidation of data for the purpose of the study. A two-year cohort study has been installed and is currently being monitored on a site-specific basis depending on acreage, available equipment, and environmental conditions. AP will visit farms in-person to assess conditions, record observations, and communicate with producer partners about the progress of treatments.
Research Objective #1 Timeframe: *AP has implemented an approved timeline extension + project modification to adapt to adjustments in the work plan to extend research period to April 2023- April 2025; educational materials + workshops to be produced in 2025 along a similar timeline as the original submission; see approved modification request.
Progress Report Updates for December 1, 2025:
Ongoing farm trials and data collection were completed in Spring 2025. See photos below from the final data recording session.
| Andrew Trump | Tom Menezes | Richard Kodani | Brett Lomont | Shawn Pila | |
| Treatment A - Mowing |
10 |
14 | 30 | 7 | 0 |
| Treatment B - Weed Mat | 10 | 8 | 10 | 8 | 12 |
| Treatment C - Mulching | 10 | 10 | 14 | 8 | 18 |
Research Objective #2) Through HUC’s farmer network, assess the effectiveness of three practices for feral ungulate control during new breadfruit orchard establishment or existing orchard expansion. Sustainable feral ungulate control methods to be compared were identified in collaboration with participating producers and include: physical barriers constructed from wire, rubber materials, and existing permanent fencing. The number of treatments was reduced to 3 types in order to accommodate producer preferences, available equipment and acreage, and consolidation of data for the purpose of the study: cages, tires, and permanent fencing. Pallet fences were left out as Producers considered them unsightly and would have required additional treatment for weather protection as well as making weed management more difficult than cages or tires. A two-year cohort study has been installed and is currently being monitored on a site-specific basis depending on acreage, available equipment, and environmental conditions. AP will visit farms in-person to assess conditions, record observations, and communicate with producer partners about the progress of treatments.
Research Objective #2 Timeframe: AP has implemented an approved timeline extension + project modification to adapt to adjustments in the work plan and the loss of one of the initial project partners to extend research period to April 2023- April 2025; educational materials + workshops to be produced in 2025 along a similar timeline as the original submission; see modified schedule for more information.
Progress Report Updates for December 1, 2025:
**AP has implemented the approved timeline extension + modification to accommodate adjustments in the work plan/installations in the field. One producer dropped out of the trial program and was successfully replaced by another producer with similar conditions, Shawn Pila.
Ungulate prevention treatments and data collection have been completed at 5 of the 5 producer sites in Spring 2025. Below is a table showing how many trees are represented in each treatment style, and see photos below from the final data recording session.
| Andrew Trump | Tom Menezes | Richard Kodani | Brett Lomont | Shawn Pila | |
| Treatment A - Wire Cages | 0 | 14 | 21 | 0 | 30 |
| Treatment B - Used Tires | 0 | 7 | 20 | 0 | 0 |
| Treatment C - Pallet Triangles | 0 | 5 | 0 | 0 | 0 |
| Treatment D - Permanent Fencing | 30 | 0 | 0 | 21 | 0 |
Project End Date: 12/31/2025
1 - Site Planning Meeting w/ Farmer Cohort ( This portion was complete as of 3/31/2023; see above tables for details)
4/2/2022
5/1/2022
2 - Research Observation Period: Ungulate Control - Completed
5/2/2023
5/2/2025
3 - Research Observation Period: Weed Management- Completed
5/2/2023
5/2/2025
4 - Site Visit 1: Complete as well as additional quarterly data checks
5/5/2023
5/28/2023
5 - Site Visit 2: Complete as well as additional quarterly data checks
10/1/2023
10/31/2023
6 - Site Visit 3 - Complete as well as additional quarterly data checks
5/5/2024
5/28/2024
7 - Site Visit 4 - Complete as well as additional quarterly data checks
10/1/2024
10/31/2024
8 - Site Visit 5 * Removed from schedule as it is after trial period ending
5/5/2025
5/28/2025
9 - Site Visit 6 * Removed from schedule as it is after trial period ending
10/1/2025
10/31/2025
10 Develop and Design Technical Fact Sheet: Completed
5/3/2025
7/1/2025
11 - Ungulate Control Video Development: Completed
5/3/2025
8/1/2025
12 - Weed Management Video Development: Completed
5/3/2024
8/1/2025
13 - Workshop 1: Completed
9/1/2025
9/29/2025
14 - Workshop 2: Completed
10/1/2025
10/31/2025
15 - Workshop 3: Completed
11/1/2025
11/30/2025
16 - Project Evaluation and Assessment + Reporting
12/1/2025
12/31/2025
Include Photos Here:
Image 1: Shawn Pila - Cage and mulching treatment
Image 2: Shawn Pila - Cage and mulching treatment wide shot
Image 3: Shawn Pila - Cage and weed mat treatment
Image 4: Shawn Pila - Cage and weed mat treatment row (right), cage and mulching treatment row (left)
Image 5: Brett Lomont - Weedmat treatment
Image 6: Brett Lomont - Mowing treatment
Image 7: Tom Menezes - Cage and Weedmat treatment
Image 8: Tom Menezes - Cage and Weedmat treatment
Image 9: Richard Kodani - Cage and Mowing treatment
Image 10: Richard Kodani - Cage and mulch treatment
Image 11: Island Harvest - Mulching treatment
Image 12: Island Harvest - mulching treatment
Five farmers from HUC’s farmer network on Hawai‘i Island participated in this study from May 2023 to July 2025, representing a total of 150 young breadfruit trees. Each farmer was provided with necessary materials including mulch, weed mats, staples, fencing, and tires, in order to create their management solutions. Farmers were also compensated $135 per quarter each year for performing regular maintenance, such as mowing, throughout the duration of the trial. All farmers received support from HUC staff to access supplies, create management plans, and collect data. Although formal data collection ceased in early 2025, some farmers continued the management techniques from the trial while others decided to change course or implement other strategies. Each farmer participated in a final survey between June and July 2025 recapping their experience with the trial. The quantitative data collected does not support significant or confident statistical analysis of the findings, and results are best summarized as a qualitative analysis, provided below.
Weed Management: Each farmer was visited periodically throughout the trial to assess and score the effectiveness of treatments at a particular site. Scores were assessed seperately for Mowing, Mulching, and Weedmat categories, and given a score of 1 - 4 for Weed Prevelance both “At Perimeter” and “Within Dripline” of trees. Scoring rubric: 1 = No growth, 2 = Minimal Growth, 3 = Significant Growth, 4 = Extreme Growth/Tree Loss
- Mowing resulted in an average score of 2.75 at the Perimeter, and 2.96 Within Dripline.
- Mulching resulted in an average score of 2.85 at the Perimeter, and 2.72 Within Dripline.
- Weedmat resulted in an average score of 2.45 at the Perimeter, and 2.4 Within Dripline.
At first glance, these results suggest that Weedmat is most effective at keeping weed growth minimized at both the tree dripline perimeter and within the perimeter. However, 4 out of 5 farmers participating in the weed management trial decided to remove their weed mat at the conclusion of this trial, as they stated issues with weeds growing through the mats over time and getting caught in the mowing equipment, which created even bigger issues and costs. On the other hand, all farmers who utilized mulch shared their plans to continue mulching their trees with their materials of choice - palm leaves, grass clippings, macadamia branches, or woodchips. The quantitative data results are also somewhat skewed, as one farmer experienced a mechanical failure with his tractor mower early in the trial, and another was unable to keep up with mowing and mulching at his trial site because extreme drought in his region required farm activities to be focused on currently producing crops that were more critical to his operational viability. This inability to mow affected in their mulching scores and vice versa, which suggests there is some nuance regarding how these practices supplement or complement each other, and this nuance is not reflected directly in the data. It also highlights the realities and challenges farmers in Hawaiʻi face every day, as well as the pratical challenges faced when conducting farmer-led field trials.
In summary, a total of 31 young trees were lost due to Weed competition - resulting in a 79% survival rate. Only 20% of participants found weedmat to be an effective weed management solution for establishing their young breadfruit trees, while 100% of participants found mulching AND mowing in combination to be preferred, acknowledging that just mulching or mowing alone would not be an effective weed management strategy for successful establishment of young breadfruit trees.
Ungulate Management: During site visits, a similar scoring structure was utilized to assess the effectiveness of tree cages and tires at preventing damage from feral ungulates. Damage was scored “At the Perimeter”, “Trunk”, and “Foliage”. Scoring rubric: 1 = No growth, 2 = Minimal Growth, 3 = Significant Growth, 4 = Extreme Growth/Tree Loss.
- Cages resulted in an average score of 1.53 across all categories.
- Tires resulted in an average score of 2 across all categories.
These scores suggest that Cages are more effective at preventing damage across all areas of trees than tires. However, no protected trees were observed to be damaged or lost directly by unglates. Damage was assessed by Weeds inundating around and within the cage or tire protection. This suggests that tree protection materials and design also need to allow for easy management of weeds, as well as preventing ungulate damage in order to be an effective solution. Of the farmers participating in the ungulate prevention trial, the two who utilized tires to protect from pig disturbance chose to leave the tires on their trees after the trial concluded, and even implemented this practice into other orchards they manage. Similarly, those who utilized tree cages were content with leaving the fences around the tree. However, all farmers were interested in the idea of fencing off the entire perimeter of their orchards to prevent ungulates from getting in rather than protecting individual trees. The two farmers who already had their farm fenced prior to the trial expressed that, although the fence helped to minimize pest disturbance, it did not prevent pigs from reaching the trees entirely.
In summary, both cages and tires were found to be an effective strategy for deterring feral ungulate pests, while the nuances around material costs for cages versus the labor cost of hauling and cutting tires, might best be addressed by a farmerʻs particular context and preference.
Research outcomes
Overall, no treatment alone was selected unanimously by farmers in the trial to be the best practice for weed management or ungulate disruption prevention. All participants found benefits to mulching and mowing for weed prevention, and were divided on the value of tires and cages for ungulate prevention. While some found tires and cages to be an effective strategy for deterring pigs from eating young trees, some farmers expressed concern about weeding through the cages and the challenge of eventually removing the tires once the trees had out-grown them.
All participants found weed mats to be a frustrating treatment, mostly because it required extra care and caution when mowing to ensure the plastic strands would not get stuck in any mowing equipment. One farmer expressed concern about using plastic on his trees, out of fear that it wouldn’t be able to be removed thoroughly or properly disposed of once it wasnʻt needed. He shared a preference for natural treatments - no plastics, or chemicals - to manage weeds. This sentiment was shared by most farmers, even though some acknowledged that they are considering incorporating herbicides into their weed management practices to make maintenance easier.
Based on the outcomes from the management styles and treatments evaluated in this trial, it was determined that farmers establishing ʻulu trees could benefit from further research around this topic. Some examples include:
- Testing of various tree cage design and materials for effectiveness at deterring ungulates while also minimizing or eliminating weeding within the cages
- Cutting of tires before installing as barriers could be trialed to determine efficacy and if the added labor up front is worth the ease of removal and reuse
- Research into the benefits of various forms of mulch would help inform farmers mulching techniques; farmers in our trial used a mixture of grass clippings, wood chips, palm leaves, and macadamia nut branches. Further exploration into indigenous polynesian mulching methods and soil benefits of different kinds of mulch applied to breadfruit trees, in addition to their ability to suppress weeds, could be beneficial
- Establishment of various ground covers or cover crop species in the tree rows as part of field prep before tree planting should also be explored to compare cost benefit to that of weedmat as a weed management technique
Other considerations:
Two of the farms who participated in the trial were heavily affected by drought, as all of Hawaiʻi experienced some of the driest years on record during the trial period. Two others were affected by abnormally heavy winds, which farmers also indicated had an impact on the health and establishment of their trees, regardless of management methods. This highlights the natural challenges of field trials while also reinforcing the need to continue best practice development of young ʻulu tree establishment.
Education and Outreach
Participation summary:
Multiple different education and outreach methods were utilized.
- Infographics were designed for both the Weed Management, and Ungulate Management trial findings. They were printed on a one-page hand-out, front-and-back, for physical distribution at meetings and events. (See links below)
- A video overview highlighting the trial and findings was created. It is posted for free public access on our website and on our YouTube channel.
- A dedicated webpage was created on our website to provide a trial overview and host both the video and the infographic PDFs for download.
- Materials produced were shared again via our monthly farmer Newsletter, and to our social media followers.
- An in-person Farmer-to-Farmer Knowledge Sharing panel discussion was held at our 2025 Annual Member meeting where this trial and the farmers experiences regarding weed & ungulate management were the focus.
- Panel Discussion was recorded and is viewable on our YouTube channel.
Information products
- Webpage - WSARE Farmer-Led Research: Weed & Ungulate Management
- Infographic - Weed Management
- Infographic - Ungulate Management
- Youtube Video - Weed & Ungulate Management for Young ʻUlu Tree Establishment
- Panel Discussion Recording - https://youtu.be/MUuXei5JjRE
Many physical one-page handouts were distributed at our 2025 Annual Member Meeting in September 2025, the Maui Food Summit also in September 2025, our Oahu member meeting at Kualoa Ranch in October 2025, and the Smoke it Up feral pig educational event in Puna also in October 2025. They will continue to be distributed as free physical resources for tabling at future events. The webpage created for these resources have received 76 views since being published in October 2025, and our video has since received over 829 views on YouTube, with 17 “likes” and no “dislikes”. The panel discussion engaged over 100 people in person, most of whom are member ʻulu farmers, or prospective farmers, and in large part our target beneficiaries of these trial learnings.
It is our intent that these educational resources will continue to contribute to farmer knowledge, helping them plan ahead for successful management when establishing young ʻulu trees. The insight gained from this trial will aid in our farmer technical assistance and the resources generated will be utilized as evidence and reinforcement in communications whenever possible.
Education and Outreach Outcomes
These lessons and resources should be included and emphasized both as new members join our cooperative and when communicating with farmers interested in starting new ʻulu production. The website, video, and pdf resources can all easily be shared via email or other online education opportunities such as webinar presentations. The pdf handouts will become a staple resource in our paper copy portfolio for educational tabling at events and workshops which we conduct around Hawaiʻi.
We have created informational handouts to share with our member farmers and broader community about our findings from this trial. These handouts include an evaluation of each technique based on cost, efficacy, and other materials required for success. We also circulated pictures of trees for visual references. Since each treatment worked well in different conditions, with no one treatment being perfect on its own, we wanted to provide our members with important pros/cons of each treatment
Ungulate damage prevention in young breadfruit orchards
Weed management in young breadfruit orchards