51 



petioles form serried ranks of slender, durable columns; the tiers 

 of tough foliage interlace into a dense canopy that excludes all 

 direct sunlight from the ground below. It is practically impos- 

 sible for an\' seed-plant to germinate and grow up through an 

 uluhi thicket — the ground is wholly occupied by rhizomes, and 

 the leaf-canopy means light starvation to any struggling seedling. 



Uluhi usually begins its invasion of a new area from the upper 

 portion of the slope, and gradually extends its range down the 

 hillside and over the ridge, obliterating all other vegetation save 

 trees and bushes. The damage which uluhi has done to the 

 native forests is difficult to estimate. It may be safeh- stated 

 that thousands of acres, once occupied by diversified indigenous 

 and endemic flora, are now covered by practically pure stands of 

 uluhi. From the standpoint of forest management uluhi is an 

 undesirable intruder, as it thoroughly prevents the development 

 of seedling trees in the regions which it has preempted. Further- 

 more, the large amount of dry woody material in uluhi thickets 

 is much more dangerous from the standpoint of forest fires than 

 is the sappy, non-combustible vegetation of the rain forests. 



Gleichenia dichotoma has completely taken possession of a very 

 considerable proportion of the Hawaiian trails. It should be 

 noted that many of the Hawaiian mountains are deeply carved 

 by valleys and gorges, wh'ch are separated from one another by 

 narrow and precipitous forest-clad ridges. The old native trails 

 ran along the crests of these ridges. When cattle, sheep, and 

 goats were introduced, in the latter part of the eighteenth cen- 

 tury, and permitted to roam and breed unchecked, these animals 

 increased in prodigious numbers. The\' made serious inroads 

 upon the native forests, following the ridge-crests and contour 

 lines and destroying the underbrush. The uluhi, hitherto held 

 in repression under the forest cover, rapidly invaded the clearings 

 made by the cattle and goats, overran these places, and invaded 

 the rapidly receding native forests. 



It is difficult to give a quantitative idea of the present extent 

 of uluhi. It forms more or less pure stands along scores of miles 

 of native trail, and over thousands of square rods of valley wall 

 and hillside. In many instances it has filled small valleys from 

 side to side. 



