INTRODUCED PLANTS AND ANIMALS. 271 



not only brought in a host of both beneficial and injurious plants and animals 

 from abroad, but through tillage, has brought about changed conditions in the 

 natural environment. These sweeping changes have affected the primitive na- 

 tural history of the Hawaiian Lslands more than all other agencies put together. 

 Enormous areas of land have been cleared of the natural growth of forest 

 and field and usually put under artificial irrigation, with the result that more 

 radical changes have been made in the character and use of the land of the 

 islands, in one generation, than was brought about by the operations of the 

 primitive inhabitants during the whole period of their occupation of the group. 

 Such wide-spread changes in the character of the country have been reflected in 

 numerous remarkable changes in the native fauna and flora. In ninnerous in- 

 stances, the extension of agriculture must be credited with the extermination of 

 many forms of life formerly common in such sections as are adapted to the 

 purposes of the planter and the ranchman. 



The Si'GAR Industry. 



Foremost among the industries of this class is the production of sng;'r. 

 AH other field crops dwindle to insignificance in comparison with it. Few- 

 places in the islands where cane can be grown at all, will yield less than thirty or 

 forty tons, and from that up to sixty and seventy tons to the acre. Such a yield 

 of green stuff can hardly be obtained from any other farm crop, and tlie develop- 

 ment of the industry has been as remarkable as the yield. 



( aiic is iiDW cultivated extensively on the four main islands, l)eing planted 

 from near the sea-shore up to elevations of about two thousand feet. As a rule, 

 however, it is the rich lands skirting the islands up to 500 feet that con- 

 stitute the chief sugar-growing sections. The maximum area that can be pat 

 under cultivation for this crop has been about reached, there being approximately 

 80,000 acres now planted to cane which yield on the average about 500,000 tons 

 of raw sugar annually. The yield per acre varies greatly according to the char- 

 acter of the soil, and the position of the plantations, whether in rainy or rainless 

 regions, the amount of fertilizer employed, and so on. 



Tender favorable conditions ten and a quarter tons of sugar have been the 

 average yield for an entire plantation ; while single acres have given much higher 

 yields. S(ime lands less favorably located fall far bcldw this yield. Next to 

 soil and climate, one of the most important factors in the production of a good 

 crop is the amount and character of the water used. Salt in the water, if in any 

 considerable amount is detrimental, and often ctnulitions are such that one hun- 

 dred grams to the gallon would absolutely prevent the plant's growth. 



As to the original introduction of sugar-cane into Hawaii, little is known. 

 There are writers who think the islands in the south Pacific were the original 

 home of the sugar-cane, since there are peculiar species there that are found no- 

 where else. It is argued that the plants were introduced from there into Hawaii 

 by the natives. But the cultivation of cane has been carried on so long in 

 widely distributed regions that the real home of the plant is lost in antiquity. 



