Haleakala Crater is now a cool, cone-studded reminder of a once-active volcano. Streaks of red, yellow, gray, and black trace the courses of recent and ancient lava, ash, and cinder flows. The volcanic rocks slowly break down as natural forces reduce them to minute particles which are swept away by wind, heavy rain, and intermittent streams.

Modern geology indicates that the Hawaiian islands are situated near the middle of the "Pacific Plate," one of a dozen thin, rigid structures covering our planet like the cracked shell of an egg. Though adjoining each other, these plates are in constant slow motion, the Pacific Plate moving northwestward several centimeters per year. Scattered around the world are many weak areas in the earth's crust where magma slowly wells upward to the surface as a "plume." Here volcanoes and volcanic islands, such as Maui, are born.

This constant northwestward movement of the Pacific Plate over a local volcanic "hot spot", or plume, has produced a series of islands one after another in assembly line fashion. The result is a chain of volcanic islands stretching from the island of Hawai'i along a southeast-northwest line for 4,050 kilometers (2,500 miles) toward Japan.

Maui, one of the younger islands in this chain, began as two separate volcanoes on the ocean floor; time and again, eon after eon, they erupted, and thin new sheets of lava spread upon the old, building and building, until the volcano heads emerged from the sea. Lava, wind-blown ash, and alluvium eventually joined the two by an isthmus or valley, forming Maui, "The Valley Isle." Finally, Haleakala, the larger eastern volcano, reached its greatest height, 3,600 meters (12,000 feet) above the ocean—some 9,100 meters (30,000 feet) from its base on the ocean floor.

For a time, volcanic activity ceased, and erosion dominated. The great mountain was high enough to trap the moisture laden northeast tradewinds. Rain fell and streams began to cut channels down its slopes. Two such streams eroding their way headward created large amphitheater-like depressions near the summit.

Ultimately these two valleys met, creating a long erosional "crater." At the same time a series of ice age submergences and emergences of the shoreline occurred; the final submergence formed the four islands of Lanai, Molokai, Kahoolawe, and Maui.

When volcanic activity resumed near the summit, lava poured down the stream valleys, nearly filling them. More recently, cinders, ash, volcanic bombs, and spatter were blown from the numerous young vents in the "crater" forming multicolored symmetrical cones as high as 180 meters (600 feet).

Thus this water-carved basin became partially filled with lava and cinder cones, and it came to resemble a true volcanic crater.

Several hundred years have passed since the last volcanic activity occurred within the crater. This stillness in Maui is attributed by modern geology to the constant northwestward movement of the Pacific Plate. As the oldest islands on the northwest end of the chain have moved farther away from the plume— the source of new lava— they have ceased to grow; the ravages of wind and rain and time have thus been able to reduce them to sandbars and atolls.

Maui has shifted a few kilometers from the plume's influence, and Haleakala, too, is destined to become extinct. Though dormant now, about 1790, which is quite recent in geologic time, two minor flows at lower elevations along the southwest rift zone of Haleakala reached the sea and altered the southwest coastline of Maui. Today, earthquake records indicate that internal adjustments are still taking place in the earth's crust, but at present, no volcanic activity of any form is visible in the crater nor at any other place on the island of Maui. Perhaps Haleakala could erupt again; we just don't know.

Though Maui is no longer growing, the youngest island in the chain, Hawai'i, is enlarging. And as plate drift continues, it is even probable that in the distant future, a new volcanic island will appear to the southeast of Hawai'i, the Big Island.

In contrast to the red and yellow, gray and black lava ash of Haleakela Crater are the lush greenness and abundant waters of the Kapahulu section of the park. Here the visitor is greeted by a chain of pools of ever changing character, some large, some small, and each connected by a waterfall or short cascade. But 'Ohe'o, the stream joining the pools, has many moods, and at times becomes a thundering torrent of white water burying these quiet pools as it churns and plunges headlong toward the ocean. The upper rain forest above the pools receives up to 635 centimeters (250 inches) of rainfall a year and flash floods can and do occur here.

A pastoral scene of rolling grasslands and forested valleys surrounds the pools. Ginger and ti form an understory in forests of kukui, mango, guava and bamboo, while beach naupaka, false kamani, and pandanus abound along the rugged coastal cliffs. Pictographs, painted by long-forgotten artists, and farm plots once flourishing with cultivated taro and sweet potatoes, remind us of an age when the ali'i— Hawaiian chiefs— ruled this land.

In the higher elevations, a vast native koa and 'ohi'a rain forest thrives, just as it has for thousands of years, still relatively undisturbed by the influences of man. It is here that the endangered Maui nukupu'u, Maui parrotbill, and other native birds still survive in a delicately balanced environment. Protection of this ecosystem will help preserve some of this rare birdlife. The Hawaiian Islands, thousands of kilometers from a continental land mass, support a complex system of plants and animals. More than 90 percent of the native species are found only on these islands. What events took place to create this assemblage of life so severely restricted in range?

A tiny seed caught among a bird's feathers, fern spores borne aloft by strong winds, and insects cast ashore with floating vegetation are means by which life can cross an ocean. For every one that successfully survived the trip, thousands, perhaps millions, failed. But time was not a critical factor, and thus over millions of years several hundred of the hardier life forms established populations on the new islands.

Time and extreme isolation were essential for the development of Hawai'i's unique native life. Isolated from the remainder of its kind and living in a strange environment, a small breeding population is especially subject to evolutionary development. In some instances, changes have been so pronounced that it is difficult, if not impossible, to trace ancestries to continental forms.

On the other hand, all mammals— except for a small brown bat and monk seal— arrived on these islands through man's intentional or accidental aid. Being unnatural, their presence has greatly upset the natural balance here. Wild pigs, initially brought by early Hawaiians, root today through the wet areas of the park. Goats, introduced by Europeans, browse throughout the crater. These two exotics are the most serious threat to the native plant and animal populations. But other introduced species inhabit the park such as the predatory mongoose, released in sugar cane fields to control rats and mice (also introduced). All of these exotics continue to threaten the natural relationship which would have evolved between organisms and their environment in the absence of interference by modern humans. Thus, the Park Service has embarked on an exotic plant and animal control program aimed at perpetuating the values for which Haleakala National Park was established.

Hawai'i is noted for its unique birdlife, and many species are found nowhere else. The golden plover commonly seen from September to May is famous for its migratory flights to and from Alaska. You may also see the 'apapane, 'i'iwi, 'amakihi, and nene which are among those birds native only to the Hawaiian Islands. The 'i'iwi is one of the most beautiful of all Hawaiian birds, with a bright scarlet body, black wings and tail, and inch-long curved bill. The 'apapane is also scarlet, but has a white belly and black legs and bill. The bright green and yellow'amakihi is known for the speed at which it searches for nectar and insects. However, most of the birds you will see along park roads— pheasants, chukars, skylarks, mockingbirds — are introduced forms. These, too, have taken their toll of native birdlife — as the carriers of bird diseases and competitors for territory and food.

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