85 



for which the plains are too warm, thrive better in the more uniform cli- 

 mate of the higher altitudes. Thus Fesca^ mentions that cocoa thrives 

 best at an elevation of about 500 m., Arabian Coffee from 600 to 1200 m., 

 and more, and tea from 1000 to 2000 m. For sugar cane, however, places 

 are necessary in which occur periods of high temperature. Accordingly 

 the cultivation of sugar cane on the sub-tropical plains often reaches even 

 to the 35 parallel of latitude, in Mediterranean regions to the 36 parallel of 

 latitude where the heat temperature for two to three summer months rises 

 above 25°C. The cultivation of sugar cane for factories, however, even in 

 narrow tropical zones is seldom successful higher than 300 m. Indeed it is 

 planted higher up but then only used for the purposes of propagation be- 

 cause of the rapid decrease in the sugar content. At such heights, however, 

 the cane escapes the "sereh disease" so much feared at present and on this 

 account it has been proposed that the plantations for the sugar be regene- 

 rated by making propagating fields with the proper cultural ^'arieties at high 

 elevations and using as stock the material from these for cultivation on the 

 plains. 



In other tropical plants the uniformity of the climate is not the decisive 

 factor but the high summer temperatures necessary for the maturing of the 

 fruit. Thus in the narrower tropical zone cocoa palms are found at an alti- 

 tude of 1000 m. but fruit is rarely produced at an elevation of 900 m. In 

 the same way Fesca cites the grape fruit which endures cooler winter tem- 

 peratures but requires a high summer temperature to mature its fruit. On 

 this account its fruit will ripen in Japan between 31 and 32 degrees latitude 

 Vv ith an annual mean temperature of i6.5°C. while in Bandoeng on Java at an 

 elevation of 714 m. and an annual temperature of 22.7°C. no fruit ripens. 

 In Japan during the months of July and August the temperature is high 

 enough to ripen the fruit when the monthly mean temperature exceeds 26° C 

 and even in September is more than 24°C. Such temperatures, however, 

 are not found in Bandoeng. 



Tea is cultivated advantageously in mountain environments. The tea 

 plant loves abundant moisture, hence is naturally a sub-tropical plant. Tak- 

 ing advantage of the climate of high elevations, it can be grown successfully 

 in the tropics. Thus it is found on Java and Ceylon and in India up to an ele- 

 vation of 2000 m. ; the highest plantations in the Himalayas often lie at 

 about 2200 m. Tea from the higher localities is in fact more highly prized. 

 To be sure, greater quantities of leaves are harvested on tropical plains but 

 the quality of the leaves is poorer. 



It is a mistake to attempt the cultivation of coffee on plains without 

 other shade. Coffee is a tropical plant from high elevations demanding uni- 

 formity of climate. The failure of the crops on the plains m.ay often be 

 traced to the great fluctuations in temperature and moisture much more 

 noticeable there the less the care taken for shading. In the sub-tropical zone 



1 Der Pflanzenbau in den Troppn und Subtropen von Prcf. Dr. Fesca. Vol. I. 

 Berlin, Sufserott, 1904., p. 41. 



