TROPICAL SOILS — PENDLETON 445 



had dropped very rapidly. Miliie was convinced that neither the 

 peasants' lack of skill nor soil erosion in any form could be blamed 

 for the ahnost complete abandonment of the holdings when he visited 

 the area. 



Milne also describes conditions in a forest reserve in Trinidad, 

 where temporary settlers for one year only had cut the forest, made 

 charcoal, and raised one crop of food in lieu of wages. He stated 

 that the Forest Department had, however, experienced the greatest 

 difficulty in establishing the desired stand of valuable (indigenous) 

 trees on land that had been cleared and cropped in this manner. On 

 the occasion of Milne's visit the Conservator of Forests expressed 

 the opinion that giving over the groimd to the cultivator for even one 

 year had been an expensive mistake. The replanting operations had 

 been liandicapped thereby to the point of defeat. The only hope of 

 replacmg natural forest by commercial forest lay in preserving the 

 continuity of forest conditions through the transition as far as possi- 

 ble. In other words, the forest soil must be maintained as an entity, 

 without changing it first into something else by alien processes of 

 tillage and exposure. 



Milne concludes that — 



both these Trinidad soils had, in fact, a fertility quite sufficient to maintain 

 mixed forest, or to grow satisfactory forests of commercial timbers, but they had 

 this fertility only so long as the reactions of forest upon soil properties were 

 inaintained without interruption. It was not expressable through field crops, 

 because the clear felling, burning and tillage necessary in preparation for such 

 crops has, as it were, dismembered the soil as a working system, and the "scrap" 

 that was left did not provide the makings of an agricultural soil. Not even a good 

 forest soil could be rebuilt from it ; there had been loss of essential parts and the 

 mechanisms of a year or two before could not be restored to working order. 



Once a tropical forest is cut and burned and the land cleared, most 

 of the mineral nutrients from the forest growth are dissipated. Of 

 course, in the ashes the minerals are freely soluble, but the young 

 crop being grown can take in only a small part of the liberated 

 nutrients, and the rest are washed deep into the soil by the heavy 

 rains of the summer. Certainly at least 90 percent of all the plant 

 nutrients are quicky washed below the limited range of the roots of 

 any crop or annual plant growth. A second year's crop is almost 

 impossible to raise because the sandy soil is so poor ; the farmers leave 

 it and clear more forest land. The abandoned land is gradually 

 occupied by herbs, wild bushes, and small trees. It is obviously un- 

 economical to use commercial fertilizers on the soils for the production 

 of subsistence crops for they do not, and cannot, justify the expense. 

 As Milne emphasized, once the soil-forest system is broken, the 

 cycle interrupted, it is quite impossible to restore the forest-soil 

 relationships. 



