The ancient, tree-covered cinder cone, one of the most distant bastions of Mauna Kea’s inland flank, is surrounded by more recent Mauna Loa lava flows, only a few dozen yards from the intersection of Saddle Road and Mauna Kea Observatory Road, not far from the boundary of the Army’s Pohakuloa Training area.

Over the decades, the hill has been scarred by cinder quarrying, littered with beer bottles and field ration wrappers, and trampled by thousands of tourists and residents, who usually stop by only for a quick hike up the steep trail behind the hunter check-in station on the Mauna Kea side of the hill. The reward for their effort is a view that is truly breathtaking – both figuratively and literally, given the strenuousness of the brief climb. Most people then chug right back down, hop in their cars and continue their journey to somewhere else.

That’s unfortunate, because the real treasure of Pu’u Huluhulu is on the other side of the hill, and it needs to be experienced slowly.

Pu’u Huluhulu is a kipuka, a mall patch of forest isolated by lava flows. Kipuka are islands within an island, tiny worlds unto themselves. Because of their isolation, they become evolutionary engines: the small plant and animal populations within them can mutate with surprising rapidity, adapting to the special conditions of each place. Biologists on the Big Island have found new subspecies of insects, for insance, kipukas that have only been cut off for a few hundered years.

Kipuka Pu’u Huluhulu Native Tree Refuge is a special place, even for a kipuka. It contains more than 10,000-year-old vestige of the mighty koa-mamane cloud forest that once ringed Mauna Kea’s upper slopes.

Most of that forest has since disappeared, replaced by cattle range. But Pu’u Huluhulu, moated by a series of lava flows – the most recent was in 1935 – has become a refuge for an amazing diversity of species that have few natural defenses against grazing animals and introduced predators. At least nine native bird species have been known to live in or visit the kipuka. Cinder-quarrying destroyed some of the hill’s vegetation but much of the primitive forest is still largely intact.

For those who wish to explore this miniature world, the best time to arrive is early morning, when the sun shines across the trees, making the birds easy to spot.

There are two ways to access the refuge. One is through the gate behind the hunter’s station. But the better route is from a small unpaved parking lot on Mauna Loa Observatory Road, the one-lane asphalt strip that passes on the Hilo side of the pu’u. Beside the lot is a pedestrian gate through the fence that the Division of Forestry and Wildlife has erected to protect the kipuka from pigs, not deterred even from lava flows. Visitors should be sure to close the gate behind them, and to pick up the trail brochure from the wooden box beside the gate.

Just beyond, a steep path known as the Apapane Trail immediately climbs into a world that is both alien and familiar, even to veteran Big Island hikers. Old friends take on strange new forms in this place. Pukiawe, common as a small, low-growing shrub on the lava flows of Hawaii Volcanoes National Park, grows to 15 feet here. Naio, a 60-foot giant at lower altitudes, grows only half that high in this kipuka. A’ali’I, most familiar to national park-goers as a medium-sized shrub with pinkish-red winged seed posds, grows into small trees here.

One of the more common plants on the pu’u’s clinkery Hilo-side slope is the mamane, a small, twisty tree whose yellow flowers resemble a pea plant’s, for good reason: like the pea, the mamane is a legume. Also growing on this slope is a large patch o akala, the native thornless raspberry. The huge berries are delicious – but leave them for the birds who pass the seeds on to start new akala patches in exchange for a tasty meal. In this kipuka birds have priority over humans.

The glory of the kipuka, though is the grove of huge koa trees. There are koa of all ages from tiny seedlings still bearing their kiawe-like “baby leaves” to giant, twisted, mossy “grandmother” trees that look like the work of a hundred generations of bonsai masters. The mature trees have crescent-shaped adult “leaves” that are actually flattened, elongated versions of petioles, the little stems that connect the leaves to branches in most trees.

Flying through the branches are birds that seldom appear in the rangeland north of the Saddle road. Scarlet-and-black ‘apapane fill the air with songs as varied as the plant life beneath them. Somewhat rarer are the I’iwi, which look much like the ‘apapane except for their exaggerated, curved, salmon colored bills. Greenish-gold amakihi, perhaps the most common native bird in the kipuka, flash among the small trees and thrive on a multiple diet of berries, bugs and nectar. Wren-like elpaio perch with their tails hiked straight up the air. Drab little oma’o lurk in the brush, more often seen than heard; their harsh call has been likened, variously, to rusty door hinges, a crow with a sore throat, or, as the trail brochure puts it, “a radio being tuned between stations.”

Although the refuge’s official trail system is only about half a mile long, it’s easy to spen hours there. For one thing, a lot of steep uphill walking slows the pace. And visitors should allow themselves time to get lost. The brochure’s oversimplified map of the seven marked trails doesn’t show many windings, nor does it mark a confusing number of unofficial and former trails. (Wilderness paths, like streams, tend to re-rout themselves around major obstacles over time, so be prepared to spend time guessing which branch of the trail goes on, and which ends in a fallen tree.) The result is a genuine, three-dimensional maze – through a fairly benign maze. Besides, it’s not that big a kipuka; no one is lost for long, unless they leave the trail entirely. If that happens, the steep slopes and a’a can be unforgiving.

Despite the area’s small size no one sees all that it has to offer at the single visit. The more often one visits, the more one can come to appreciate the little kipuka’s endless ability to generate special moments in time.

Here is a sampling of Pu’u Huluhulu moments:

  1. Sitting beside an ancient but withered koa that somehow clings to the edge of the summit and over the sheer face of the old cinder quarry, mists are rolling down from Mauna Kea, making the quarry floor below barely visible. Suddenly, silently, a brown form looms out of the mist, less than five feet away: a pueo, a native owl. It wheels and plunges toward the quarry floor again, misses a mouse skittering for cover, then swoops upward again, soaring on the updraft created by the wind on the hill’s face. The owl hangs there, listening, obscured from its prey by mist instead of night. Then it swoops again.

  2. It’s 6:30 a.m., barely dawn The weather is miserable, a precipitation that the Hawaiian language calls “kauanoe,” rain so fine it feels lie a cold touch, but soaks through clothing to the skin beneath.

    Out of that rain-fog a faint honking drifts. Then four nene geese appear out of the fog, calling to each other as they wing from one kipuka to another. They fly directly overhead, so low that you can hear the beat of their powerful wings. Then they disappear into the fog again, in the direction of Pohakuloa.

  3. It’s mid-afternoon on an intensely clear day. Hiking on the Koa Trail, on the leeward side of the kipuka, there may be a grandmother koa in another time and a less remote place, the giant trunk would have been carved into a canoe. Here, however, some trail-maintenance crew has chainsawed the fallen trunk into crude seats, so hikers can rest and admire the view of Mauna Loa through the gap that the tree probably created when it fell.

A lace of snow gleams on a giant volcano’s summit. Far below, the tiny ribbon of Mauna Loa Observatory Road laces among the black and brown lava flows.

Making a way up the ‘Apapane Trail, you spot movement among the branches of a mamane tree above you. The late afternoon sun gleams on the feather of two little silver-and-gold birds. The birds seem totally engrossed in each other as they play a game of tag, hopping from branch to branch after each other, their feathers blending beautifully with the golden blossoms and gray branches. Then the endangered species – the palila, which subsists mainly on mamane, opening the seed pods with their parrot-like beaks – flutter off together, into the forest.

According to the current trail brochure, no palila sighting has been recorded in the kipuka in 15 years. “If you spot a palila during your visit,” requests the current trail brochure, “please notify DOFAW (Department of Forestry and Wildlife” by calling 974-4221.”

The brochure defines “Pu’u Huluhulu” as “shaggy Hill.” According to “The Pocket Hawaiian Dictionary,” “huluhulu” can mean body hair, eye-lashes, fur or fleece or feathers. “Hulu” can also be translated as “esteemed” or “prized.” Pu’u Huluhulu is a forested hill that looks shaggy. But it is also a place of many birds and feathers and a very special, prized place. For the little hill in the middle of the Saddle, all three meanings seem to fit.