HAWAIIAN TREE FERN AS A SOURCE OF STARCH 9 



Table 2. — The rate of groicth of the tree fern and amount of starch core it 



produces annually 1 







• (a) 



(b) 







(c) 



(d) 



(e) 



(0 





Tree No. 



Weight 

 of starch 

 core 



Length 

 of starch 

 core 



Diameter of starch 

 core 



Vertical 

 distance 

 between 

 successive 

 fronds 



Annual 

 vertical 

 growth 2 



Esti- 

 mated 

 length 

 of time 



required 

 for 



growth 3 



Starch 

 core 

 produced 

 annually * 











Top 



Bottom 



5-spiral 





1 



Pounds 

 34.5 



Inches 

 66 



Inches 

 5.4 



Inches 

 3.8 



Inches 

 4. 12 



Inches 

 4. 44 



Years 

 14.9 



Pounds 

 2.31 







DO 



80 



7.3 



6.7 



<±. Uu 



A 38 



~\A 8 



-t. oZ 



I::::::::::::::::::::: 



76 



5.4 



6.1 



4 



4. 32 



18.5 



4.11 



4. 



87 



128 

 72 



4.8 



5.4 



4. 57 



4. 93 



26 



3. 35 



5 



58.5 



6. 1 



4. 1 



4.5 



4. 85 



14.8 



3. 95 



6 



72.5 



101 



5. 7 



4.5 



3. 49 



3. 76 



26.9 



2.7 



7 



15 



33 



4. 1 



4.5 



4. 13 



4. 45 



7.4 



2. 03 

 .99 



8 



11 



41 



3.8 



2.43 



3. 41 



3.68 



11. 1 













Average 













4. 35 





2. 97 



















1 The 5-spiral measurements are used in these computations because the coefficient of error in measure 

 ment is less than in case of the 3-spiral. 



2 c multiplied by 5.39, divided by 5. 



3 b divided by d. 

 * a divided by e. 



Table 2 shows that the average vertical growth of the tree fern is 

 fairly uniform and averages 4.35 inches annually, and that the an- 

 nual production of starch is subject to wide variations due to differ- 

 ence in diameter of the starch core. The annual increment in starch 

 core averages 2.97 pounds. 



Sections of the bark of a large number of trees growing, at vary- 

 ing altitudes were slabbed off to permit of measuring the distance 

 between successive fronds for a distance of about 1 foot. The data 

 so secured, while only approximate, would seem to show that the rate 

 of growth of the tree fern is practically constant between sea level 

 and an altitude of 3,500 feet. Measurements of other species of tree 

 ferns showed that they make about the same rate of growth as does 

 Cibotium chamissoi. 



The very slow rate of growth of the tree fern brings into very 

 serious question the feasibility of planting cuttings of different parts 

 for starch production. It would require at least 20 years to grow 

 a tree fern of sufficient size to cut for starch, since it has been found 

 unprofitable to cut trees having less than a 60-pound starch core. 

 Twenty years is a rather prohibitive length of time, especially for a 

 small industry, to wait for replanted areas to furnish new material. 



As a result of the investigations it was concluded that, while the 

 tree fern can be successfully planted on cut-over areas, its rate of 

 growth is too slow to make such a procedure advisable under present 

 conditions. 



CHEMICAL COMPOSITION OF THE CORE 



Preparatory to analyzing the core the outer fibrous sheath and the 

 hard inner bark were stripped from it. The }^ello wish- white core 

 was then shredded and the nonreducing and reducing sugars were 

 determined. The methods of analysis recommended by the Associa- 



