On a quiet hillside above Haleiwa town, Seneca Klassen is planting cacao seedlings on the last of his 14 acres, next to trees he planted a few years ago that are now laden with the nubby pods that yield chocolate.

On the other side of the island, his new factory in Kalihi is gearing up to produce the first bars of Lonohana Estate Chocolate, made 100 percent in Hawaii, this spring.

Klassen, a founding partner of Bittersweet Chocolate Café in San Francisco, may be relatively new to farming, but he knows a lot about chocolate. After traveling to Latin America as a chocolate connoisseur, he began planting cacao in 2009 on Oahu’s North Shore, with visions of Napa Valley in his head.

"Chocolate is a very dynamic and interesting food," Klassen said. "It deserves attention and it delivers a lot of pleasure in exchange. In the back of my mind was the example of the wine country. I want people to see how their chocolate is made from start to finish.

"One of the main reasons we wound up here is that I think there are some very interesting flavors that I’m convinced have something to do with this particular location. Of course, being on the most visited of the Hawaiian islands, we have a potential audience to tap into."

Klassen is among a flurry of cacao farmers, researchers and chocolatiers exploring the specialty crop across the islands. They will come together with the chocolate-loving public at a pair of events this weekend sponsored by the Hawaii Chocolate and Cacao Association, a nonprofit formed a year ago that has seen interest in its subject matter soar.

The Hawai‘i Chocolate Festival at Dole Cannery Shops on Saturday will offer tastings of Hawaii-grown chocolate, cacao plants for sale and displays on how cacao becomes chocolate from noon to 5 p.m. And a conference Sunday at the University of Hawaii at Manoa will examine Hawaii’s future in the chocolate world, featuring local experts along with national authorities like Ed Seguine of Mars Chocolate and Art Pollard, founder of Amano Chocolates.

"The growth is no longer linear, it’s really becoming kind of like an explosion," said Daniel O’Doherty, who has a pulse on the local cacao picture as a leader of the Hawaii Statewide Cacao Trial. "We get a lot more email and a lot more phone calls. A lot more people are planting."

H.C. "Skip" Bittenbender, Hawaii’s best-known cacao authority, is principal investigator on the trial, a project of UH-Manoa’s College of Tropical Agriculture and Human Resources.

The Hawaii Department of Agriculture doesn’t track cacao as an individual crop because production is small and the statistics office has limited staff. But Bittenbender, an extension specialist and faculty member at the college, recently completed the 2013 Hawaii Cacao Survey and its results will be released at the conference.

The survey shows an upward trajectory for the fledgling crop. The 26 cacao farmers who responded to the survey reported a total of 46 acres in cultivation last year and an expected 62 acres by the end of the year. Within five years, they project having 113 acres in cacao collectively.

An acre of cacao typically has 400 to 500 trees, O’Doherty said.

While most of the farms — 15 out of 26 — are on Hawaii island, three-quarters of the state’s cacao acreage is on Oahu. Statewide, farmers reported harvesting 30,500 pounds of dry bean equivalents last year. Cacao trees do not bear fruit for at least three years and take several years to reach full maturity.

Waialua Estate Chocolate is the big player in the Hawaii market, with 23 acres in cacao along the banks of Kaukonahua Stream. Its parent company, Dole Food Co., pioneered the crop on former sugar cane land.

Waialua’s "single origin" chocolate, manufactured by Guittard Chocolate Co., is marketed as bars as well as premium couverture chocolate, favored by local chefs such as Alan Wong.

"There’s been a convergence of things happening in the last five years," said Derek Lanter, sales and marketing manager at Waialua Estate, as he gave a tour of the orchards to an award-winning barista from Australia who uses Hawaiian chocolate in her specialty drinks. "The local food movement and the know-your-farmer movement have helped move things along. With that change and a growing sense of regional taste, things that are unique Hawaii, we’ve had this surge in culinary tourism."

The Original Hawaiian Chocolate Factory, a pioneering chocolatier in Kailua-Kona that uses only Hawaii-grown cacao beans, has been joined by newer artisan outlets on Oahu such as Madre Chocolate and Manoa Chocolate Hawaii.

Madre Chocolate recently brought home honors from the International Chocolate Awards, and two of its bars — Coconut Milk and Caramelized Ginger, and Triple Cacao — were finalists at the 2013 Good Food Awards.

Cacao is typically found in tropical environments and requires year-round warm weather to thrive. Hawaii is the only state in the country where it can be grown, but the supply of Hawaii cacao remains tiny.

"People making chocolate here are challenged to get cacao from Hawaii," said Lanter, president of the Hawaii Chocolate and Cacao Association. "Chocolate makers are saying grow cacao, grow cacao. The demand is there … HCCA gets a lot of inquiries from Korea, China and Japan, people who want to buy but we don’t have the supply yet."

O’Doherty warned that growing cacao requires patience. It demands a big up-front commitment of money and labor, with no financial return for at least three years while the trees mature. The beans are fermented, which is a tricky process, and the equipment to make chocolate is costly.

"The early years are difficult," O’Doherty said. "A lot of people run into problems. The single limiting variable in Hawaii that people don’t account for is the trade­winds. Cacao hates strong wind. Another limiting variable to cacao production here is having a large enough mass to ferment."

He gets calls from hobbyist farmers who don’t know anything about the crop. "Now there is this cacao fever," he said. "People who have two or three acres, they imagine dancing around with money, holding hands in a circle around cacao trees. It’s grossly unrealistic."

The statewide cacao trial has 14 sites scattered across the island, from relatively dry Pearl City to rainy Hana, Maui. Planted at each site are mini-orchards of 40 trees — four grafted samples of 10 different cacao trees with varying attributes, including productivity, disease resistance and flavor. Planting for the trial began in 2009 and the first sites are bearing fruit.

"We’re trying to span all the different microclimates that exist in Hawaii," said O’Doherty, who grafted each tree. "The idea is to see how these trees respond to these different climates, rainfalls and temperatures. And ultimately, is it going to cause a change in flavor?"

The goal is to ferment and process the cacao into chocolate, and learn how genetics and environmental difference affect yield and chocolate quality in Hawaii. The trial runs through 2017, but some results will be available by the end of next year.

"The way that chocolate is fermented and the soil that it grows in affects how it tastes, just like wine," said Amy Hammond, who volunteers as executive director of the Hawaii Chocolate and Cacao Association. "I see so much potential for the industry here. It could be the next Napa Valley. People get as excited about chocolate as they do wine. And fortunately, they can even pair it."

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On the Net:

» www.hawaiichocolate.org