AEOLIAN EROSION IN HAWAII 



BY C. S. JUDD 

 SUPERINTENDENT OF FORESTRY 



AN unusually good instance of ceolian erosion is to be 

 seen on the island of Kahoolawe in the Hawai'an 

 group, which I have recently visited. It is a striking 

 illustration of damage done by goats and sheep and wind. 

 This island, which is one of the smallest of the group, 

 and only ten miles long, six miles wide, and 1425 feet 

 above the sea at its highest point, was proclaimed a Ter- 

 ritorial Forest Reserve in 

 1910 with the idea that it 

 could be reclaimed from its 

 present deplorable condi- 

 tion, which has resulted 

 from over-grazing during 

 the past fifty years. Ka- 

 hoolawe was always a more 

 or less barren island, for 

 in the early days its inhos- 

 pitable shores were used as 

 a place of exile for crimi- 

 nals and historical records 

 show that at no time were 

 there more than eighty 

 Hawaiians living there. 



In 1864 the island was 

 leased by the King for fifty 

 years as a sheep ranch. 

 Wild goats, descendants of 

 those brought by Vancouver 

 and other early navigators, 

 were already on the island, 

 and these with the 

 sheep, which soon 

 multiplied and 

 overran the island 

 by the thousands, 

 upset the balance 

 of nature on the up- 

 per reaches which 

 were exposed to the 

 full force of the con- 

 stant trade winds. 

 The consequence 

 was that the re- 

 maining turf on 

 about one-third of 

 the island at the 

 upper elevations 

 was destroyed, and 

 the loose soil ex- 

 posed in this man- 

 ner soon began to 

 be carried out to sea 

 by the wind. This 



WHAT THE WIND HAS DONE 



WHi wili tree on Kahoolawe Island, Hawaii, undermined by the strong trade 

 winds blowing the soil around it out to sea, after sheep and goats had cropped 

 the turf so closely that the wind tore it off and exposed the underlying soil. 



AN AERIAL BATTLEFIELD 



On the summit of Kahoolawe Island, Hawaii, lie trunks of dead trees killed when the strong trade 

 winds swept away the soil about their roots after the soil had been exposed by over-grazing by sheep 

 and goats. 



aeolian erosion has been going on for at least forty years, and 

 ship captains always know of their approach to Kahoolawe 

 on windy days by the cloud of light red dust that pours off 

 in the lee of the island. In a few protected places on the 

 summit, islets of soil from six to ten feet high, crowned 

 with turf, remain as mute testimony of pristine condi- 

 tions, but the soil on the remainder of the summit of the 



island has been blown away 

 until nothing remains but 

 bare hardpan, as bleak and 

 as desolate as the bad lands 

 of the Dakotas, and still 

 scoured by the howling 

 trade winds. 



One of the accompanying 

 illustrations shows how a 

 native wili wili tree, Ery- 

 thrina monosperma, has been 

 undermined by wind erosion 

 and left stranded, as it were, 

 on this shore of desolation 

 with only a few roots to 

 carry on the functions of 

 life. In the lee of the tree 

 there still remains a mass of 

 original protected soil which 

 has been augmented by 

 dust drift. 



Although the reclama- 

 tion of the summit of the 

 island seems hope- 

 less, unless stone- 

 wall barriers to the 

 wind are erected at 

 great expense pre- 

 liminary to tree 

 planting, the re- 

 maining two-thirds 

 of the island gives 

 greater promise of 

 early improvement. 

 The first step in the 

 plan of reclamation 

 has been to get rid 

 of the wild stock 

 on the island, and 

 during the last eight 

 years over 4,000 

 goats have been ex- 

 terminated. I have 

 returned from the 

 island with a party 

 of fifteen members 

 239 



