36 BULLETIN 354, U. S. DEPARTMENT OF AGRICULTURE. 



under a forest-tree shade, like coffee, but, unlike coffee, it does best 

 in the low country at elevations below 500 feet. It is chiefly of 

 interest here as offering a suitable means of restoring a forest cover 

 and providing an agricultural crop on some of the less fertile cane 

 lands, 1 where a forest cover is particularly desirable because of its 

 influence on bird life so necessary to the control of insect pests. 



FOREST INFLUENCES.2 



Forests make their presence felt through their influence on climate, 

 on stream flow, and on soil erosion. In a country as abundantly 

 watered as is Porto Rico whether the forests cause slightly more rain 

 hi the aggregate matters little. Within the forests, particularly those 

 in the mountainous interior, the temperature of the air is appreciably 

 milder and the humidity relatively higher than hi the open. One 

 effect of this may be observed in the formation during the dry season 

 of clouds above the forests of El Yunque and vicinity, when none 

 exist elsewhere. These rapidly disappear as they pass on to the 

 westward and come in contact with the columns of heated air rising 

 from the open slopes and cultivated valleys toward Juncos and 

 Caguas. The modifying influence is likewise manifested in the cool 

 air which descends after sundown into the open cultivated valleys 

 from the wooded slopes of the coffee district. 



The most important influence of the forests is hi the checking of 

 floods and erosion, though the conditions in Porto Rico are such as 

 to make control of floods by forest ation alone impossible. Through- 

 out a greater part of the year the forest soils, except those of the 

 limestone hills, are nearly, if not quite, saturated with moisture. 

 Steep slopes and rain in the form of brief but torrential downpours 

 are the rule and complete a combination favorable to most rapid 

 run-off. These make it necessary to supplement forestation by a 



i Cacao undoubtedly could be grown as profitably in Porto Rico as in Granada (British West Indies), 

 where conditions of configuration, rainfall, soil, trade winds, etc., are very similar and where an even greater 

 density of population prevails. According to a " Report on the Economic Resources of the West Indies" 

 (by Daniel Morris, assistant director Royal Gardens Kew, in Kew Bulletin of Miscellaneous Information, 

 Additional Series 1, 189S) cacao was first planted in Granada on mountain lands as it formerly was in Porto 

 Rico, the lowlands being entirely in sugar estates. But later it was tried on the lowlands and found to 

 rival sugar in productiveness. In 1S95 Granada was said to be the only West Indian colony of Great Britain 

 that was independent of sugar. An especial feature of the cultivation of cacao is that it can be raised to 

 advantage on small holdings. 



2 Of more than passing interest in this connection are the following observations by Col. Flinter (see 

 Bibliography), written in 1834: "The government has most wisely ordered that three trees should be 

 planted for every one cut down. It is to be hoped that this order may be rigorously enforced; for, in the 

 first place, wood is the great and principal agent in the atmosphere for the attraction of the clouds, * * * 

 If these laws on this head are carried into force by the local magistrates the island will always have on it an 

 inexhaustible source of timber; but if, on the contrary, these useful precepts are not followed, water will 

 become scarce; the rivers will dry up; the fields will become scorched savannas for want of moisture; the 

 cattle will find neither food nor shade from the noonday sun; and this beautiful and fertile island will at 

 once be deprived of its enchanting verdure, its fertility , and its riches. This is not the dream of imagination 

 or the ridiculous prognostication of ideal ills. I am aware that this can not happen before the expiration 

 of a century; but it is the duty of governments and individuals to look forward to posterity. It is their duty, by 

 wise and prudent measures, to foresee and prevent at the present day the ills which may be inflicted on future 

 generations by undue considerations or concessions of temporary interests.' 1 (Italicizing is the author's.) 



