1648 A NATIONAL PLAN FOR AMERICAN FORESTRY 



The best known of these, and the largest as well, covers about 12,000 

 acres of the Luquillo Range and is now under Federal management. 

 The aggregate of all the other remnants is believed to be well within 

 5,000 acres, making the total area of original forest less than 1 percent 

 of the total land area. The Insular Forest Service estimates that 

 Puerto Rico has not more than one eighth of its area in growing 

 forests of any kind, including the areas under coffee culture. 



Of the 1,100,000 acres in the third classification above, there are 

 about 400,000 acres which have been assessed as " timber and brush 

 lands" and a few thousand acres more classed as swamps and largely 

 under mangrove. Of the " timber and brush" areas, the bulk are 

 found in the southern, southeastern, and southwestern parts of the 

 island. Insular authorities estimate that altogether 400,000 to 

 450,000 acres are unsuited to profitable agricultural use and should 

 be kept perpetually in forest. 



About 95 percent of the land area is in private ownership. Of the 

 less than 130,000 acres remaining in public ownership, by far the 

 greater part lies in the mountains. Federally owned lands within the 

 Luquillo National Forest amount to 13,885 acres. Insular forests 

 account for about 40,000 acres, of which 25,000 acres are in the 

 uplands and 15,000 acres in mangrove swamps. Thus, less than 

 54,000 acres of the public lands are under definite control and 

 management. 



Forests make their presence felt^ through their influence on climate, 

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

 watered as Puerto Rico whether the forests cause slightly more rain 

 in the aggregate matters little. The most important influence of the 

 forest is in the checking of floods and erosion, though the conditions 

 in Puerto Rico are such as to make the control of floods by forestation 

 alone impossible. Throughout a greater part of the year the forest 

 soils in the mountains 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 

 succession of reservoirs and a cleaning up of the channels if any 

 noticeable reduction of the eroding effects of floods is to be accom- 

 plished. 



Forests aid in conserving the water in the soil. The trees increase 

 enormously the amount of water that goes into the soil instead of 

 running off on the surface and then help the soil to retain it. 



Forests influence erosion in two ways: By reducing the force and 

 interrupting the passage of the run-off in the catchment areas around 

 the headwaters of the streams, they slow up the washing away of the 

 surface layers of the soil and greatly impede gullying. At the same 

 time, the ability of the run-off to transport eroded material is very 

 considerably lessened. 



The greatest damage is done when the run-off is gathered into the 

 streams of the island and reaches the foothills country, wherethee 

 heavy clays of the interior are replaced by the lighter and more 

 readily eroded coast soils. The rivers are generally too short to choke 

 up and overflow ; yet they are continually widening and shifting their 

 channels, cutting off islands from adjoining fields, and undermining 

 their banks. The close relation of the existing forest cover to stream 

 flow and erosion is not difficult to observe. For this purpose, the 



