- :-- "J·i.;'!·~·~~- "' >-c. .HAwAn AGRICULTURAL EXPERIMENT STATION . ' . ' - . ' HONOLULU, HAWAII Under,the~lalo~ortia~ _ UNITED STATES DEPARTMENT OF AGRICULTURB - BULL.ETIN No. 53 · · TJIE :HAWAIIAN TREE FERN AS ,A COMMERCIAL SOURCE.OF-STARCH . BY J.C. RIPPERTO:N, Chemist ... I111111ed JIIIJ, i92' WASHINGTON GOVERNMEN'l'. PRINTING OF'FICE / - '. HAWAII AGRICULTURAL EXPERIMENT STATION, HONOLULU . _. - ,. - - . .. .. LU1uler the. stipervisioµ of _the Olilce ot Expetjment Statloll.!J, , tJ_nlted States Department of Agriculture] ~ ·, E. W. ALLEN, Chief, Office of Ea;periment Stations;' WAL'.J'EB H. EVANS, Ohief, Division of Ins1tlar Statw,ns,' Qffice of Ea;periment Stations. .'-- STATION STAFF J .. M. WESTGATE, .Agronomist in Charge. w. T. POPE, HortilJ-u;lturist. -~ H. L. CHUNG, ~peoialist in Tropical Agronomy. J. C. RiPPEBTON, Chem.ist. · It A. GoFF, In Charge of Glenwood· Subswtion and E(/)ten­ sion Agent for the Island of Hawaii. MABEL GREENE, Boys' an(l Girls' Club Leader• ..... HAWAII AGRICULTURAL EXPERIMENT STATION HONOLULU, HAWAIi Under the supervision of the UNITED STATE~ DEPARTMENT OF AGRICULTURE BULLETIN No. 53 Washington, D. C. July 11. 1924 THE HAWAIIAN TREE FERN AS A COMMERCIAL SOURCE OF STARCH ;J, C. RrPPERTON, Chemist CONTENTS Page Page Introduction--------------------­ 1 Chemical composition of the core__ _ 9 Botanical description------------- 2 Physical properties of tree-fern Occurrence In Hawa!L________ ___ _ 3 starches -----.------------~---- 10 Starch making from the tree fern __ Studiesand growth of me _thod________________s of propagation __ _ 13 3 Summary ----------------------- 15 INTRODUCTION Many generations ago the natives of Hawaii discovered the value 0£ the tree fern as a source of food. They found that they could use the tree fern in place of the taro and the sweet potato, which constituted their favorite and staple food crops; and, likewise, that they could live indefinitely upon a diet of tree fern and wild game when they were defeated in battle and driven from the seashore to the mountains. Usually, they stripped the trunk of the bark 1 and baked the starchy core in an underground oven. It is not un­ likely that the natives obtained starch from the tree fern, since they were familiar with the art of extracting it from the arrowroot. Many attempts have been made within recent years to produce tree-fern starch on a commercial scale. None of these proved suc­ cessful, however, due to insufficient capital for the proper develop­ ment of the product, until 1920 when tree-fern starch was success­ fully manufactured and appeared on the local markets in a form suitable for use as food and for laundry purposes. Although some feared that the new industry would soon destroy the beautiful tree-fern forests, the Hawaii Experiment Station re­ ceived many requests to aid i.n developing it. To satisfy those who looked unfavorably upon the industry, the station made a pre­ liminary investigation to determine the effect on the forests and on water conservation of cutting over tree-fern areas. As a result of 1 In this publication the word "bark " ls used to describe all that portion of the tree­ fern trunk except the central starch-containing core. 94678-24--1 ----------·-····----·--------·-·· 2 BULLETIN 53, HAWAII EXPERIMENT STATION the investigation, it was found that even a considerable thinning o:f the ferns for starch production is not noticeable. The tree fem :falls to the ground o:f its own accord, or is easily pushed over, upon reaching maturity, and since only the mature trees are utilized for starch making, relatively few trees per a.ere would be cut for this purpose. A rather extended program o:f work was therefore outlined, ( 1) to determine the feasibility of planting tree ferns on cut-over areas for the establishment of permanent-producing areas, and (2) to make a study of the properties and uses of tree-fern starch. "\Vhen it was found that the rate of growth of the tree fern is too slow to make it commercially practicable to replant the fern and the necessity of building roads and fences to get the necessary raw material be­ came apparent, hopes were abandoned of establishing the industry on a large and permanent basis in Hawaii. It is not unlikely, how­ ever, that the industry might be made a permanent one under the economic conditions existing in other tropical countries in which cer­ tain species of the tree fern are indigenous. This bulletin, reporting the results of certain observations, to­ gether with data on the Hawaiian tree fern as they apply to its use as a source of starch, has been prepared because of the scientific interest which the industry has aroused and because o:f the potential importance of the tree as an emergency crop for the island popula- tion in case of interruption of shipping. · BOTANICAL DESCRIPTION 2 Rock lists eight species of Cibotium, two occurring in Guatemala1 one in southern Mexico, one in the monsoon districts o:f east Asia, one in the Philippines, and three that are peculiar to the Hawaiian Islands. The following botanical description of the two most im­ portant species in Hawaii may be of interest.2 Cibotium menziesii.-* * * Stipes green, stout, with a ventral and two lateral furrows, tuberculate and shaggy at the base with a straightish and long brownish-yellow glossy pulu which changes higher up into stiff, long blackish hair, and as such often covers the entire stipes; frond with stipes 18 to 36 dcm. or more long and 9 to 15 dcm. or more broad, pyramidal-oblong, coriaceous, naked underneath or sometimes with minute furfuraceous dots; the rhachis asperous with scattering tubercles; pinnre with a stipe of 25 to 50 mm., oblong, 4.5 to 7.5 dcm. long, bea1·ing 18 to 24 pairs of free pinnules besides the pinna­ tifid apex; most pinnules shortly stipitate, linear lanceolate, acute, cut half­ way or more, often to the rhachis at the base, into oblong rounded or entire segments, which are separated by broad sinuses; veinlets very prominent, simple or forked; sod 8 to 14 on a lobe, also fringing the sinus. Involucre corneous, large, a little more than 1 mm. to nearly 3 mm. in width, the outer valve fornicate and large, the inner flat and narrower. C. chamissoi.-* * * Stipes 12 to 24 dcm., brownish, smooth, clothed at the base with a pale fawn-colored lustreless, matted or cobwebby pulu, fur­ furaceous or naked above ; frond 12 to 24 dcm. long, chartaceous, the under face green or dull glaucous and generally oovered with a pale cobwebby pubes-· cence; lowest pinnre 4.5 to 7.5 dcm. long, with 24 to 28 pairs of pinnules, these, shortly stipitate, linear lanceolate 12.5 to 15 cm. by 16 to 20 mm. acute, the lower ones cut to near the rhachis into oblong, straightish, rather obtuse seg-­ ments with narrow sinuses, the basal segments entire and not deflected; veinlets little prominent; sori 8 to 14 to a segment, the involucre small about 1 mm. wide, chartaceous. • Rock, J. F. The indigenous trees of the Hawaiian Islands. p. 89. • Rock, J. F. The lndlll'enous trees of the Hawaiian Islands, pp. 91-93. HAWAIIAN TREE FERN AS A SOURCE OF STARCH 3 Hillebrand 4 lists another species, 0. glaucum, but states that it is rather rare. Oibotium chamissoi, or " Hapu " as it is popularly known, is easily recognized by its yellow pulu or hair and its comparatively short, stocky growth. In many forests it constitutes more than 50 per cent of the entire tree-fern growth. The trunk sometimes attains a height of 16 feet, but usually does not exceed 10 feet. The diameter of the trunk is usually 8 to 12 inches. (Pl. I, fig. 1.) 0. menziesii, 9 or,: Hapu Iii," is distinguished by the brownish or blackish pulu which covers the stipes and fills the crown. Occasionally it attains a height of 40 feet and frequently a diameter of 3 feet. (Pl. I, fig. 2.) Another species, commonly known as the " Meu," is easily recognized in the Hilo district by its very slender trunk, smaller fronds, dull, lusterless, rather scant, yellowish-brown pulu, and nearly naked stipes. (Pl. I, fig. 3.) The "Arnau" (Saclleria cyatheowes), although a different genus of tree fern, is also of interest since it is exceedingly common in occurrence and has a starchy core. OCCURRENCE IN HAWAII The tree fern is found in all parts of Hawaii ,vhere there is an annual rainfall of 100 inches or more. It grows on nearly all the mountains, but occurs in dense forests only on the islands of Kauai and Hawaii. On Kauai the forests are too inaccessible to be of importance for starch production, but on Hawaii they occur in al­ most unbroken stretches from sea level to an elevation of 6.000 feet or more. These long stretches are reached both by rail and auto­ mobile roads running from Hilo to the Kilauea Volcano. The wind­ ward slopes of the Manna Kea and Manna Loa Mountains are one continuous tree-fern forest, the belt extending from the Puna dis­ trict to the Hamakua district being about 10 miles wide and 40 miles long. In general it is estimated that there are 400,000 acres of tree­ fern forests on the island of Hawaii alone. A very large part of this area is within the forest reserve or on Government-owned lands. from which it is ille~al to cut the tree fern. There are, however; many thousands of acres of privately owned land on the island of Hawaii, which in its present state is of little value because the dense growth of tree ferns unfits it for pasture and the heavy cover­ ing of leaf mold keeps the soil too wet for general agricultural pur­ poses.