MILPA AGRTCULTUEE, A PRIMITIVE TROPICAL 
SYSTEM. 
By O. F. Cook. 
[With 15 plates.] 
It is usual to write of the Tropics as a world of teeming, inexhaus- 
tible fertility, a rich storehouse of food and raw materials waiting 
only to be drawn upon to support the ever-growing populations and 
industries of temperate regions. The reality is very far from this 
traditional idea. Tropical lands in general are neither more fertile 
nor more continuously productive than those of temperate regions. 
Though tropical temperatures make it possible for plants to grow 
for 12 months in the year instead of for the short summer season of 
temperate countries, continuous all-year production of foods or other 
important crops requires specialized, intensive systems of agriculture, 
which as yet have been developed and applied in only a few regions. 
Under the j)rimitive sj^stem followed in most tropical countries, 
production not only is less continuous than in temperate regions, but 
may decline rapidly and even cease altogether. Regions that sup- 
ported large populations and were the scenes of great activity in 
former times are now uncultivated. Primitive civilizations destroyed 
the very basis of their own existence. Nations may pass without 
history, and yet leave marks of devastation. Instead of the natural 
resources of production being still untouched, most of the tropical 
world is far from a virgin state, a fact too often overlooked in tropical 
undertakings. The woody vegetation of many tropical regions is 
" bush," or secondary growth, instead of original virgin forest. Very 
old bush approximates the original forest, but it is possible to dis- 
tinguish many stages of reforestation and to estimate roughly the 
period that has elapsed since the land was used for agricultural pur- 
poses whether decades or centuries ago.^ 
^ See Vegetation Affected by Agriculture in Central America, Bureau of Plant Industry 
Bulletin 145, 1909. Other features of primitive agriculture, reforestation and domesti- 
cation of plants have been treated in the ifollowing papers : Shade in Coffee Culture, U. S. 
Dept. of Agi-iculture, Div. Bot. Bui. 25, 1901 ; The American Origin of Agriculture, Popular 
Science Monthly, October, 1902 ; Food Plants of Ancient America, Smithsonian Report, 
1903 ; Cotton Culture in Guatemala, U. B. Dept. of Agriculture Yearbook, 361, 1904 ; 
Change of Vegetation on South Texas Prairies, Bureau of Plant Industry Cir. 14, 1908 ; 
History of the Coconut Palm in America, Contr. U. S. National Herbarium 14, pt. 2, 
1910 ; Wild Wheat in Palestine, Bureau Plant Industry Bui. 274, 1913 ; Jewish Coloniza- 
tion in Palestine, Popular Science . Monthly, November, 1913; Possibilities of Intensive 
307 
