FAQs / About Cane Burning

Why does sugarcane need to be burned?

Sugarcane is burned before harvesting to remove the unproductive leafy material that makes up 20 to 25 percent of the cane plant. The leaves contain very little sugar, but if not removed before processing the cane, they can reduce the amount of sucrose (sugar) that can be recovered from the cane stalk at the factory.

HC&S reduces its energy consumption by field vehicles and at the factory by not hauling and processing this material.

Despite our efforts, HC&S has not been able to find another economical means of removing the cane leaves other than burning. Nor is technology currently available to cost-effectively remove and produce energy from cane leaves. The energy cost of hauling and processing this additional material is higher than the value of utilizing it to produce energy.

Is cane-burning only done in Hawai‘i?

Pre-harvest burning is practiced everywhere that sugarcane is grown in the United States – including some 850,000 acres in Florida, Texas and Louisiana. It is a long-standing practice in these states, as well as most areas of the world where sugar is grown.

Agricultural burning is standard practice for many other kinds of crops on nearly 9 million acres throughout the country, including rice, wheat, corn, cotton, lentils and soybeans.

Why is some cane harvested using ‘chopping’ machines, while most cane is not?

The sugarcane you may see being cut by machines with saw blades is ‘seed cane,’ immature stalks that are ‘harvested’ after only six to eight months of growth. They are used to plant our fields of commercial sugarcane, which will be grown to maturity for approximately 24 months.

Because this cane is young, it is still erect, which makes it suitable for these choppers, unlike our mature cane that lies down, under its own weight, by harvest time. Also, unlike most of our plantation, which is rocky and/or has sloped terrain, the fields we use for growing seed cane are flat and with minimal rocks, allowing us to use this mechanical harvesting equipment.

Is burning permitted and legal?

Our burning practices comply with all state and federal laws, including the Clean Air Act. Hawai‘i state laws specifically allow agricultural burning under a permit system administered by the State Department of Health. HC&S’ permit has numerous specific conditions for burning, which we fully comply with.

Air quality on Maui meets all federal air quality standards established under the Clean Air Act, as well as state standards.

What is emitted when sugarcane fields are burned?

Emissions from burning sugarcane are similar to those from burning any other organic matter, such as wood. They include water vapor, carbon dioxide, particulate matter and carbon monoxide. Even the tubing used for our drip irrigation system is made of polyethylene, composed of carbon and hydrogen, and, if burned, would be similar to burning wood or a candle, emitting carbon dioxide and water.

Since 1987, the State has operated an air quality monitor in Kihei, directly downwind of HC&S. The station was originally located there specifically for the purpose of monitoring air quality impacts from burning sugarcane, and has never found a violation of state or federal air quality standards due to cane-burning. These standards are set to protect people’s health and the public welfare, taking into consideration the most sensitive populations – the old, young and those with respiratory problems.

Does the irrigation system burn, too?

Except for the fields adjacent to our mill, which use recycled millwater applied through a sprinkler system, the vast majority of our 36,000 acres of cultivated land are irrigated using drip technology, making HC&S the largest drip-irrigated farm in the world.

The drip tubing is buried underground to get water directly to the root of the plant. This protects most of the tubing from burning. There are some exposed areas, like the ends of the fields or rocky areas, where the tubing cannot be buried. However, since it is made of carbon and hydrogen (polyethylene), if any tubing does burn, it is similar to burning wood or a candle, emitting carbon dioxide and water.

The PVC pipes in the irrigation system are buried deep underground, except for the “risers” you might see along roadsides. The PVC pipes, risers and filtration stations are part of our permanent infrastructure so we take great care to prevent them from burning; otherwise it would be costly to replace them. Prior to burning a field, the harvesting crew clears the cane away from this equipment, wets down the area around the risers, then burns around them to avoid damaging them.

Does the carbon dioxide produced by burning have an effect on global warming?

Sugarcane, like all plants, needs carbon dioxide from the air to grow. Over its two-year growth cycle, sugarcane actually consumes more carbon dioxide than is released into the atmosphere during burning. Agricultural burning is not considered a net source of carbon dioxide.

How often do you burn? How long is the cane-burning season?

Each field is harvested, and thus burned, only once every two years. We plan our harvesting activities over an 8- to 9-month period, typically from March to November, paced to supply a steady amount of cane to the factory. This averages out to roughly 400 acres per week. The number of acres burned at one time is usually about 70 acres, but can vary depending upon field conditions and location, weather, and requirements of the factory.

During the harvest season, planting operations also are ongoing, with seed cane being cut and replanted as soon as possible to return the fields to productivity.

How do you inform the community, especially those living next to HC&S fields, about upcoming cane-burning activities?

In order to fulfill our commitment to agriculture, our employees and the Maui community, we strive to continue to be a good neighbor. We make every effort to provide the community with information about cane-burning operations in their area, before it takes place.

For many years we have used a telephone-based notification system that gives residents the ability to call in and find out about planned harvesting and/or to be called in advance. For certain fields located in close proximity to residential areas, a company representative distributes written notices door-to-door, several days in advance of the burn.

We have augmented our efforts using communication technology and now offer additional notification options for the public including web-based, text and email alerts. To sign up for these alerts, click here.

How can I be notified about upcoming cane-burning activities?

We can notify you ahead of time, by telephone, text message and/or email, of burning in your area so you can plan accordingly. Click here to sign up.

You also can call our Cane-Burning Hotline at (808) 877-6963 for recorded information about the timing and location of current and upcoming harvesting activities.

Does cane-burning cause health problems?

Studies have been conducted at HC&S by the Department of Health, the National Institute for Occupational Safety and Health, and the University of Hawai‘i. Researchers have found no evidence that sugarcane burning in Hawai‘i causes chronic respiratory conditions or other serious health problems. We do recognize that smoke – of any kind – can aggravate an existing respiratory condition. That’s why HC&S makes every effort to alert neighbors, especially those with health problems, whenever a harvest is scheduled nearby.

The air quality standards set by government, to protect people’s health and public welfare, specifically take into consideration the most sensitive populations – the old, young, and those with respiratory problems. Since 1987, the State has operated an air quality monitor in Kihei, directly downwind of HC&S, and has never found a violation of state or federal air quality standards due to cane burning.

What is sprayed on the fields, and what is the effect of burning?

HC&S uses NO insecticides on its sugarcane crop, relying instead on biological control of insect pests (‘bugs eating bugs’) since the 1800s.

Government-approved herbicides are used to control weeds primarily in the first six months of growth (young cane). By the time the crop is harvested, after about two years of growth, herbicide residues are negligible or non-existent due to their natural breakdown in the environment. We do apply a ripener about six weeks prior to harvest to increase the sugar content of the cane; tests show this dissipates prior to burning.

What preparations are undertaken prior to burning a field?

Scheduled pre-harvest burns follow a very structured procedure, and HC&S makes every effort to minimize the impact on the community.

Pre-harvest burns follow roughly 18 months of growth and an additional six-month period of ripening when the cane plant is denied water and depleted of nutrients that promote growth. This process stresses the plant and forces it to store sucrose rather than grow.

Pre-burn precautions include field preparation such as pushing cane away from and watering adjacent fields, irrigation equipment, and other structures such as utility poles. HC&S also contacts nearby residents who have requested pre-burn notification and written notices are distributed in advance to homes and businesses possibly affected.

Prior to every burn, weather conditions, mill capacity and other operational factors are assessed. Over time, a total of 44 weather monitoring stations have been installed, including more than two dozen new stations in just the last few years. We also use computerized modeling to help us to predict the best times to harvest, when impacts should be confined.

Once the decision is made to proceed, water trucks wet down the perimeter of the field and stand by. Harvest personnel are well-trained to create backfires to reduce the likelihood of a jump fire. Propane torches are used to start the fire; most fires generally last 20-30 minutes. Personnel remain onsite until the fire is out, to monitor and document the fire and any impacts, and to be ready in case of any emergencies.

How is an unscheduled burn/arson different from a pre-harvest burn?

An unscheduled burn or arson does not follow any of the structured field preparation and safety precautions that HC&S takes prior to its pre-harvest burning. Such unscheduled burning not only can decrease sugar production for HC&S, but more importantly, it can have serious impacts on our community.

FAQs / About Water and Irrigation

Where does HC&S get water for irrigation?

More than half of the plantation’s water comes from surface sources (rain water), delivered by two important ditch systems. One is the 74-mile East Maui system, built and operated by HC&S sister company East Maui Irrigation Company (EMI), which collects water from streams along the windward slopes of Haleakala. The other is the 17-mile West Maui Ditch System, co-owned and co-operated by HC&S and Wailuku Agribusiness, which collects water from four streams along the West Maui Mountains.

During dry months, rain water is supplemented by non-potable water pumped from the company’s 15 brackish-water wells.

Does HC&S need all of the water it collects?

It is no secret that a lot of water is needed to grow 36,000 acres of healthy sugarcane every day, every year. The water supplied by East Maui streams irrigates approximately 85% of our fields. The remaining 15%, or 5,400 acres, is irrigated by water collected by the West Maui system. Depending on the rainfall, some days we have more water than the plantation needs, in which case water is stored in reservoirs for future use or is left in the streams.

Do others use water that HC&S collects?

For more than 100 years, thousands of community users have depended on water collected and delivered by East Maui Irrigation Company’s ditch system.

Can HC&S use its well water instead of stream water?

We already use well water to the maximum possible. This water is supplied to approximately 36,000 residents and farmers in Upcountry Maui who rely on this county water supply. It has the highest delivery priority, even before HC&S’ use of the water.

Water collected by the West Maui Ditch System supplies HC&S as well as other farmers, businesses and residents.

Without the ditch systems that EMI and other companies built and maintain, these community users would have no water, and Maui’s arid Central Valley and Upcountry farmers would not remain productive.

Can HC&S use less water, or use it more efficiently?

HC&S is an extremely efficient water consumer.

Our East Maui water system is one of most efficient in the world, and we take great care to maintain our collection and delivery infrastructure. To make sure the correct amount of water is allocated to the various ditches and reservoirs, a sophisticated remote radio telemetry system transmits ditch flow data every eight minutes. Water flow can be adjusted at each of the company’s control and collection points.

Throughout our 36,000 acres, we have installed highly water-efficient drip irrigation to maximize use of this precious resource. In fact, HC&S is the largest privately owned drip-irrigated farm in the United States.

We also make multiple uses out of the water we collect. Water used in the factory is recycled and reused multiple times, and then is filtered and used to irrigate our fields. We use ditch water to generate clean, hydroelectric power for HC&S and the Maui community. After generating electricity, the water is returned to the ditches.

Does the diversion of stream water threaten ecological health?

None of the native species that inhabit Maui’s streams are endangered or threatened. Studies have shown that healthy populations exist even in some of the most diverted streams on Maui. While the native fish species o‘opu does need to return to a stream environment to spawn, they wait for freshets (streams that flow to the sea) to occur to swim upstream. Freshets occur even in heavily diverted streams, allowing fish to spawn.