38 BULLETIN 



ticularly suitable for this purpose and formerly were plentiful along 

 the water courses in Porto Rico. But since sugar cane has become 

 the all-important crop in the lowlands, the bamboo has been sacrificed 

 to secure a few more feet of land or because it shaded the cane planted 

 near the edge of the field. The folly of this procedure can be seen 

 in places where the extra feet of cane rows thus secured at the sacrifice 

 of bamboo and several more with them have been subsequently 

 undermined by flood and dumped into the river. 1 



The close relation of forests to stream flow and erosion is not 

 difficult to observe in Porto Rico. Compare, for instance, the lower 

 reaches of the north coast rivers, particularly those rising in the coffee 

 district or the Luquillo, with the south coast rivers, as, for instance, 

 the Portugues. The former have relatively few abandoned channel 

 beds and less spreading stream bottoms, are obstructed only by sandy 

 or gravelly bars and relatively small bowlders, and show a reasonable 

 flow of water even in the dry months. The Portugues and other south- 

 side rivers, which are largely fed by the rains falling on the steep 

 grass slopes of the Cordillera Central, have wide, dry bottoms showing 

 often no less than six different channels separated by low islands, and 

 many shoals, remnants of a former river bank. The bowlders, which 

 are everywhere strewn about, are several times the size of those in 

 the north coast rivers, the banks are often steep and undermined, and 

 the stream is of almost inconceivable insignificance on the midst of 

 surroundings indicative of such destructive power. The many 

 streams and waterfalls in the heart of the interior flow from the wooded 

 slopes (even when swollen by heavy rains) practically clear, carrying 

 but little sediment; on the other hand, the waters of the south coast 

 embayments at the mouths of the rivers are red-brown in the flood 

 season with the soil brought down by the rushing torrents. 



Many examples might be found in the Tropics of serious injury resulting from 

 destruction of the forest or of benefits following its restoration. Owing to reforestations 

 effected on a large scale, the rainfall on the island of St. Helena has actually been 

 doubled since the time of Napoleon I ; and in Lower Egypt, where in the eighteenth cen- 

 tury rain only fell on from 10 to 12 days in the year, the number of rainy days nowadays 

 reaches from 30 to 40. On the other hand, in Syria and Palestine there are numerous 

 regions which were formerly in a flourishing condition but have become arid and waste 

 in consequence of the destruction of forests. 2 In the West Indies themselves, the 

 experiences of Martinique are particularly instructive. Here as early as 1843 the man- 



i The following, which bears closely on this situation, is quoted from the 1907 report of Lorrin A. 

 Thurston, chairman of the committee on forestry of the Hawaiian Sugar Planters' Association: 



"In the past the subject of forestry has been largely treated by this association as an interesting incident, 

 but not as one of direct concern or of possible immediate benefit or profit to its members. Within tics 

 years I have heard of trees bounding fields being cut out because the shade injured the adjoining cane. 



"In all earnestness I urge upon the association that the time for this view of forestry and its possibilities 

 in Hawaii has passed, and that the preservation, propagation, and utilizing of forests and forest products 

 should from this time forth be made one of the leading features of the efforts of the planters' association, 

 both by it as an organization and through the individuals and corporations which give it its strength." 

 (Italicizing is the author's.) 



2 General report by C. Capolletti, of the proceedings of the Navigation Congress at Milan in 1905. 



