§4 BULLETIN 354^ U. S. DEPARTMENT OP AGEICULTUHE. 



the only virgin forests in the Tropics, but in many cases they them- 

 selves may not be virgin at all, but second growth.^ 



Because the rain-forest — the jungle — presents not only unusual but 

 often spectacular features which make a most direct appeal to the 

 interest and a most lasting impression on the mind, it has come to 

 typify the tropical forest in general. Yet it would be scarcely less 

 misleading to represent the mammoth redwoods or the giant fir and 

 cedar forests of our Pacific coast, or even the magnificently diversified 

 hardwood forests of the Appalachian region, as beiag the typical 

 and prevaihng forest growth of temperate North America. 



In its original forested condition Porto Rico imdoubtedly pre- 

 sented a diversity of forest formations unexcelled in any other 

 similar area in the West Indian Tropics. Of the general types found 

 throughout the Tropics, only those were impossible of occurrence 

 which result from extremes of altitude and of drought. Thus alpine 

 and desert elements were unquestionably never developed here. 

 The various formations in the order of their occurrence from the 

 coast toward the interior are as foUows: Littoral woodlands, moist 

 deciduous forests,^ and tropical rain-forests on the north or humid 

 side, and the dry deciduous forest ^ on the south or semiarid side. 



The distribution of these formations was, of course, not so simple 

 as might be imphed by the last sentence, there being more or less 

 overlapping. Remnants of these formations are, with few excep- 

 tions, still to be found in the out-of-the-way places of the island, 

 although their original balance and relative importance have been 

 very much modified.* 



1 This is very interestingly brought out in Cook's "Vegetation Affected by Agriculture in Central 

 America" (Bureau of Plant Industry Bulletin 145), from which the following is quoted: "Many localities 

 which are now occupied by apparently virgin forests are shown by archseological remains to be regions of 

 reforestation. Thus in the Senahu-Cahabon district of Alta Vera Paz, relics of two or three very different 

 types of primitive civilizations indicate that as many ancient populations have occupied successively the 

 same areas which are now being cleared anew by the coffee planters as though for the first time. 



"It does not yet appear that any considerable region of forest has been explored in Central America 

 without finding similar evidence that the present forests are not truly virgin growth. * * *" 



And again, speaking of the evidence of antiquity as exemplified by the crumbling of large earthenware 

 pots of an earlier civilization, he continues: ■ ' We can not know how long it has taken the pottery to crumble, 

 but we can at least contrast the condition of these decayed pots with other pieces of pottery placed in caves 

 of the same district in later prehistoric ages, which will appear fresh and new, as though recently burned. 

 And yet the bones beside these apparently new pots have also crumbled nearly to dust, and there has 

 been time for the surrounding coimtry to be occupied with old forests of hardwood trees, like true virgin 

 growth." He also mentions terracing of the land as showing that agriculture was formerly extensively 

 practiced and notes the presence of a type of terrace evidently designed "to hold drainage water and 

 prevent erosion * * * being frequently met with in the heavily forested region of eastern Guatemala." 



2 Called "monsoon forest" by Schimper. 



3 Also caUed "thorn- woodland" by Schimper and "chaparral" by Harshberger. 



* The natural balance and relative importance of the different formations as given by Woodward for 

 Santo Domingo on a percentage basis for the total forested area is as follows: Wet hardwood type (which 

 includes the "moist deciduous" and "tropical rain" forests of the above classification;;, 58 per cent; dry 

 hardwood type ("liti,oral woodlands" and "dry deciduous" forests), 28 per cent; pine type (lacking 

 entirely in Porto Rico, but occurring on a similar site to the "dry deciduous" forest), 14 per cent. 



