4 



BULLETIN" 53, HAWAII EXPERIMENT STATION 



The possibility of securing a large tract of tree-fern forest for the 

 establishment of a permanent starch-producing area was therefore 

 considered. Such an area would have to be strongly fenced to keep 

 out cattle and hogs, and roads would have to be built at intervals, 

 with subsidiary donkey trails, to permit of the tree-fern logs being 

 carried out. The purchase of such a tract would be feasible it it 

 could be shown that the tree-fern growth could be successfully main- 

 tained by natural methods of propagation, or by planting cuttings 

 from different parts of the fern, thus assuring a permanent and in- 

 creasing supply of readily accessible raw material. It was therefore 

 decided to learn whether parts of the tree fern could be successfull}' 

 planted on cut-over areas, and whether the rate of growth would be 

 sufficiently rapid to justify the cost entailed in establishing and 

 maintaining such an area. 



The first step in the s solution of the problem seemed to be The 

 acquisition of a detailed knowledge of the character and habits of 

 the tree fern. Since the literature was found to contain only certain 

 botanical descriptions, a series of observations was begun of its nat- 

 ural methods of propagation and growth. 



NATURAL METHODS OF PROPAGATION 



The tree fern reproduces itself in two general ways — (1) by spore 

 germination (PI. II, fig. 1) and (2) by lateral shoot development 

 (PL II, fig. 2). The spores are borne on the underside of the fronds. 

 Old tree-fern trunks and moss furnish excellent seed beds for spore 

 germination, and land that is undisturbed by cattle and wild hogs 

 is frequently literally covered with the tiny ferns. Their growth 

 is, however, very slow. 



Propagation by lateral-shoot development on the trunks of ma- 

 ture trees is much more rapid than by spore development. One to 

 three such shoots are found about each tree in varying stages of 

 development in the native forests. These increase to as many as 15 

 when the tree fern has been injured, or the soil about it trampled 

 upon by animals. The shoots begin to develop when the parent 

 tree ceases to grow or falls to the ground. It is not uncommon to 

 find, even on young, vigorous trees, one or two shoots which are 

 almost as large as the parent. The shoot soon establishes its own 

 root system and in a short time becomes independent of the original 

 fern. The crown continues to grow after the tree has fallen, the 

 fronds gradually turn in a vertical direction, another root system 

 is established at the new base, and growth proceeds almost unin- 

 terruptedly. 



PLANTING TREE FERNS 



It is a well-established fact that tree ferns can be successfully 

 propagated from crowns and lateral shoots which spring from 

 the trunk, as well as from spores, but since the entire inner core 

 of the trunk is used for starch, planting would not be feasible if 

 sections of the trunk were necessary for the production of new 

 growth: and it was not known whether the undeveloped lateral 

 shoots which are found on the average tree would develop if re- 

 moved from the trunk. Three experimental plats were therefore 



