This Pacific Island staple crop could be key to food security and land-use management in Hawai‘i

What is breadfruit and why is it important?

Breadfruit, or ´ulu, is a crop that’s gaining more attention from sustainably minded farmers, and for good reason. Their fleshy fruit are heavy with starches and can be cooked several ways, but breadfruit trees are more than just a source of food. They can be used for timber, latex, mosquito repellant and more—the inedible parts of the fruit can even be recycled into livestock feed.

Crops like breadfruit are key in agroforestry, a form of agriculture that seeks to create a more ecologically sound system of land-use management by incorporating trees into the cultivation of conventional crops. Agroforestry and other high-diversity farming systems are more sustainable than single-crop monocultures for a number of reasons.

The presence of leaf litter and other organic matter returned to the soil reduces the need for synthetic fertilizer, which means no soil acidification and no fertilizer runoff into our waterways. A variety of species makes these systems less vulnerable to pests and disease, reducing the need for pesticides and protecting farmers from total crop failure. Diverse fields provide habitat for pollinators, eliminating the need to import bees and supporting native insect populations. These systems also produce more food than monocultures on the same amount of land.

Few other trees can produce as many commercially viable products as breadfruit, so they’re a major component of agroforests in Hawai‘i and beyond.

What is the Breadfruit Phenology Catalog?

Because breadfruit is very sensitive to its climate, farmers have used it as an “indicator species” to help keep track of variations in weather conditions. By observing the timing of breadfruit flowering and fruiting, farmers can coordinate the plantings of other crops to make them more successful. Unfortunately, these cultural practices have not been well documented and the variable phenology of breadfruit trees in different climates and soil types is not well understood.

A study out of the University of Hawai‘i at Mänoa seeks to change that. The Breadfruit Phenology Catalog, coordinated by Dr. Noa Lincoln and research assistant Blaire Langston, aims to track breadfruit phenology around the state. Hawai‘i has a broad range of soils, elevation and rainfall, providing many varied climatic conditions that affect breadfruit phenology, or the study of how seasons, climate and habitat influence plant and animal lifecycle events.

“This research accomplishes several things,” Lincoln says. “It takes advantage of Hawai‘i‘s extraordinary setup as a living laboratory, it engages people as environmental observers, connecting them to their natural surroundings, and it provides important data for an underutilized crop of enormous potential. As a staple crop, coordinating and managing the production supply is a key part of developing it as part of our food supply.”

This information will be distilled into maps and shared with farmers, distributors, processors and buyers to provide information and resources that support the burgeoning breadfruit industry in Hawai‘i. “It’s really up to people at the community level to make a difference,” Langston says. “In Hawai‘i we have a problem with imported food. Part of the purpose of projects that support ‘ulu as an emerging crop is to shift that [paradigm] and support local food.”

How to get involved

The study employs the help of citizen scientists who “adopt” a breadfruit tree and provide researchers with biweekly updates and observations. Signing up and creating a profile for the tree takes about 30 minutes. After that, it’s just five to 10 minutes of visiting the tree and collecting data every other week. These observations are compiled and make up the entirety of the data collected by the project.

Kat Hiu, a senior at the University of Hawai‘i at Mänoa, has adopted nine trees in cooperation with the project. “I look forward to getting out and observing my trees,” Hiu says. “Anybody can be qualified to survey an ‘ulu tree. It’s easy to get started and all [you have to] do is count fruit.”

Nicky Davison, a lecturer at Leeward Community College, started with one tree in her yard. “It’s been pretty easy to collect data, the [online] materials have been really good at helping me to get started.” She has adopted more trees on the Leeward campus and uses them as an opportunity to give her students experience in data collection.

The use of citizen scientists is becoming an increasingly popular model for the collection of scientific data. “It’s great for people who are emerging young scientists who want to get something on their resume, who want to have a meaningful experience,” Langston says. “As a volunteer it’s a good time to learn and have someone who can help you do it.”

To get involved, visit https://breadfruit-phenology.herokuapp.com and create an account to become a citizen scientist. For more opportunities to assist in scientific research and environmental conservation, visit www.HISCB.org and become a member of the Hawai’i chapter of the Society of Conservation Biology.