Cowboys in paradise. One of the world's most unusual ranches is on Hawaii's Big Island

PICTURE a cattle roundup on the slopes of a volcano. Some of the cowboys are Japanese; a couple, Filipino. A few miles away, bottle-nosed dolphin frolic in a saltwater lagoon. A scenario out of Ripley, to be sure, but also an indication of the startling contrasts on the Big Island of Hawaii.

The cattle are part of the 50,000 that roam the Parker Ranch, an immense empire that sprawls over 225,000 acres, from the sparkling Pacific to the 8,000-foot level of snowcapped Mauna Kea. Seven-hundred miles of fence encompass what is the largest privately owned ranch in the United States.

Parker Ranch is a world of contrasts in itself. Puuopelu, the century-old home of the present ranch owner, Richard Smart (a sixth-generation descendant of the founder), is not exactly timbers and tack rooms. Instead, it houses one of the finest private art collections in Hawaii - with works by Renoir, Degas, Pissarro, Corot, Utrillo, and Chagall among its treasures. Mr. Smart started collecting with the help of neighbor Laurance Rockefeller, who had bought up some Parker acreage on the beach. There he founded the queen of Hawaii's grand resorts, the Mauna Kea, where his own stunning collection of Asian and Pacific art is displayed.

Across a drive ablaze with flowers from Puuopelu stands Mana Hale, built by the first Parker in strictly New England salt-box style, with multi-paned windows and sturdy furniture offering further contrast to the tropical setting.

The galleries and elegant public rooms of Puuopelu, as well as Mana, have been open to tour groups for some time, but, as a result of even more years of public pleas to view the day-to-day life of an enormous working ranch, Smart has initiated van tours through much of the pastureland and outbuildings. Short tours run continuously every day but Sunday; a more detailed, three-hour tour is available Tuesdays, Thursdays, and Saturdays.

All tours start at the Visitor Center, where a 15-minute video orientation gives an excellent overview of the role Parker Ranch has played in Hawaii's economy, as well as some highlights of a century-and-a-half of ranching, island-style. The Visitor Center also houses a museum of early ranch artifacts, as well as a collection of trophies and mementos of Duke Kahanamoku, Hawaii's late swimmer and Olympic athlete. (The ``Grand Duke'' was a good friend of Richard Smart.)

After visiting Puuopelu and Mana, both tours proceed to Puukalani Stables, a viewing area for ranch exhibits and a place for visitors to meet some of the hands.

Ranching in Hawaii is obviously very different from ranching on the mainland. The weather here permits year-long grazing, but the varying kinds of soil (ranging from sand to lava rock) and strange climatic conditions (especially strange during a volcanic eruption) offer unique obstacles that are fascinating to mainland farmers and ranchers.

Also included is a visit to an old ranch shack, Puhihale (House of Fire), where branding is done and horseshoes and spurs are made. Even the horses' saddles are handmade in this self-sustaining ranch community.

The Parker Ranch is world renowned for innovative programs, including its orphan-calf nursery; its selective breeding (which has not only increased the number of brood cows, but improved the percentage of those producing calves - now an astounding 85 percent); and its strong emphasis on improving animal health. After a year or so of grass-grazing, young animals weighing about 700 pounds are loaded aboard inter-island barges for their sea voyage to Honolulu. Mondays and Thursdays are known locally as ``shipping days,'' a time of chaotic activity, what with the great numbers of balky cattle that are forced to depart dry land for the first time.

The immense Parker empire is the result of a charming gift to a beneficent king. The young British explorer George Vancouver thought King Kamehameha the Great might like to sample some beef as a change from the local goat and boar that roamed the island. So he brought along several head of longhorn cattle on his voyage to Hawaii. The year was 1793.

The king took such childlike delight in the strange beasts that he decreed that anyone who harmed them would die. Within a few years, wild cattle were running rampant, trampling farmlands and terrorizing the natives.

After 10 years the decree was lifted, and a roundup began that surely must have been out of the wildest of Wild West movies. Among those who risked death while rounding up these savage creatures was an ex-seaman from Newton, Mass., John Palmer Parker. In 1809, he compared life on a whaling ship with the inducements of a tropical paradise. The choice was easy. He jumped ship and was soon befriended by King Kamehameha - so much so that Parker eventually married one of the king's granddaughters.

Meanwhile, Parker succeeded in domesticating the small herd he took as payment for his part in the roundup, pasturing them on a plot of land in Waimea. Thus, in 1815, did Hawaii's ranching industry begin, although the official date is 1847, when King Kamehameha III deeded what was royal land to Parker. (The town of Waimea, incidentally, is more commonly called Kamuela, the Hawaiian name for Samuel.) It was Samuel Parker, John's grandson, as well as John Palmer Parker II, who initiated the expansion of the ranch, acquiring vast pasturelands as well as stock. In fact, while the Western territories of the United States were still untamed, cattle ranching was becoming a sophisticated business in Hawaii.

As in the Old West, the working hands on the Parker Ranch are true cowboys. Here they're called ``paniolos'' (a corruption of ``Espanolas''), because the first cowboys imported to work the lands were Spanish and Mexican. Today you see paniolos in cowboy hats and blue jeans on horseback and in pickup trucks. Among them are descendants of the original Spanish, but now paniolos are mainly Hawaiian, Caucasian, Filipino, and Japanese.

Two Japanese paniolos made headlines here recently for each having celebrated 50 years on the Parker Ranch. There are surprisingly few working cowboys (fewer than 100) for a spread of this size, but the fact that quite a few are 20- 30- or 40-year employees attests to the idyllic working conditions. Moreover, Richard Smart has taken strong measures to strengthen the Parker bonds of legacy to the community. Land has been given for parks, civic and recreational centers, churches, health facilities, and an airport; the ranch also supports a school on its property.

Richard Smart, the great-great-great-grandson of John Palmer Parker, has had a second career in theater, including several Broadway appearances. He has built a playhouse as one of his community enterprises, occasionally appearing in a role himself. But big-name entertainers make special trips to the Big Island to appear here, too.

If you're a summer visitor to the islands, you're in for a special treat. That's when paniolos stage rodeos and horse races. The Fourth of July is truly spectacular, with a colorful ``Parker Ranch Old-Timers'' parade, followed by such rodeo events as calf-roping, bronco-busting, bull-riding, and wild-cow-milking. Spectators are welcomed free of charge.

If you go

Rates for the van tours range from $12 to $38, with special prices for children and Hawaii residents.

Reservations should be made in advance by writing to Parker Ranch Visitor Division, PO Box 458, Kamuela, HI 96743, or calling (808) 885-7655.