THE OAHU RAIN FOREST 



277 



life that lie below it. Leaving Hono- 

 lulu at early morn, our party of 

 four men traversed the narrow low- 

 land, with its wealth of exotic 

 vegetatio n banana plantations , 

 papaia orchards, flooded rice and 

 taro patches, guava thickets, alga- 

 roba groves. A half-hour's walk 

 brought us to a grassy foothill 

 the seaward outpost of one of the 

 long ridges that rise to the main 

 summit of the range. The foothills 

 are dry and hot, and are covered 

 with an uninviting, stultified growth 

 of coarse grasses, thorny lantana, 

 prickly cactus, and other pugnacious 

 weeds. These tough and dogged 

 vagabonds have exterminated from 

 Oahu's lowlands most of the indig- 

 enous vegetation. 



When we reached the lower skirts 

 of the forest we gave a shout of re- 

 lief and sat down amidst the fra- 

 grant ginger beds in the cool moist 

 shade of a kukui grove. The gray 

 trunks, wide-spreading boughs, and 

 shady domes of silver-green foliage 

 were so soothing after the glare and 

 sterility of the foothills that with 

 reluctance we resumed the labor- 

 ious climb. A few upward steps 

 lifted us from the tranquil twilight of the trees into 

 the brilliant sunshine that poured down upon the ridge 

 trail. The comb of the ridge was very narrow, never 

 exceeding a few feet in width, and dropped abruptly 

 on either side into the deep valleys. The ridge itself 

 was overgrown with bushes and stunted trees. 



We were now in the rain forest, the fourth and upper- 

 most of the plant zones that engirdle the mountains. It 

 begins at an eleva- 

 tion of 1500 to 1800 

 feet, and extends to 

 the ragged skyline 

 of the Koolaus, 

 which reach three 

 thousand feet. The 

 appropriateness of 

 the term " rain for- 

 est" soon becomes 

 evident to us. Al- 

 though but mid- 

 morning, the sun- 

 shine was at first 

 deadened and then 

 completely hidden 

 by the dull gray fog 

 that rolled down 

 over the ridge. The 

 cumulus clouds 

 that an hour before 



THE TAPESTRY FOREST 



Deeply eroded ridges and gulches in the Rain Forest 

 of Oahu Island. So steep are these luxuriously wooded 

 slopes that they have aptly been termed "tapestry 

 forests." 



A RADIANT MOUNTAIN MANTLE 

 A densely wooded ridge in the Rain Forest zone, Oahu Island, elevation about 2200 feet. These forests 

 from a distance look wonderfully rich, but the average height of the forest growth is well under thirty 

 feet. 



had dazzled us with their high efful- 

 gent whiteness, now settled lower 

 and lower over the mountains, con- 

 cealing the upper slopes and filling 

 the air with wind-driven showers. 

 The rain continued for so long a 

 time that we finally halted and en- 

 deavored to find temporary shelter- 

 This proved no easy undertaking, 

 as the ridge trail was exposed to 

 the full blast of the wind. The 

 ground was thoroughly wet, and the 

 rain seemed heavier under the 

 scraggly, crook-armed trees than 

 anywhere else. 



We turned our backs against the 

 cold, driving wind and scanned the 

 long ridge that we had ascended. 

 Its foothills were baking in the 

 sunlight ! The distant sea was blue 

 and serene, the white beach line, 

 the drowsy palms, the lowlands, 

 were all drenched with sunshine! 

 We, a few miles mountainward, 

 were under the cloud-canopy of the 

 rain forest, and the prey of every 

 pouncing shower. We abandoned 

 our original plan to ascend the sum- 

 mit, now engulfed in clouds, and 

 returned to the kukui grove. Here 

 we ate our very soggy sandwiches, 

 and in equally soggy shoes and clothing retraced our 

 trail to the sunny lowlands of Honolulu. 



This trip was our introduction to the chief factors in 

 the formation of Oahu's forest mantle abundant fog, 

 frequent rains, temperatures much lower than those pre- 

 vailing on the subtropic plains. The soil on the steep 

 slopes and ridges is water- soaked throughout the year. The 

 dense, squat, stunted woody mantle that maintains itself 



under these strange 

 conditions is itself 

 perpetually humid. 

 The rain forest oc- 

 cupies the region of 

 maximum rainfall, 

 and in this zone the 

 annual precipita- 

 tion is astounding, 

 attaining a yearly 

 average of several 

 hundred inches. 



The continuous 

 humidity of the rain 

 forest encourages a 

 profuse under- 

 growth of ferns, 

 mosses, liverworts, 

 and other lowly 

 plants. Trunks and 

 branches are envel- 



