The objective of experiment was study the growth of pioneer forest species pau-de-balsa (Ochroma lagopus) and caroba (Jacaranda copaia) to rehabilitate degraded areas from agriculture. The experiment carried out at Br-174, km 120. After the use for cassava and banana plantations the area was abandoned for 8 years. The secondary forest that took place was of low height and sparse trees. The experiment was installed at may/98 and composed by harrowed and no harrowed areas. The seedlings were planted in 3 x 3 m spacing, in 20 cm diameter by 30 cm deep holes, with 150g of fertilizer NPK (4-16-8) and dolomite limestone in the proportion 3:1. To evaluation the growth were measured the height and diameter in july/98 and each year, approximately (June/99, September/00 and May/01). The data were obtained from planted species comparing harrowed and no harrowed areas in a full random design. The survival of pau-de-balsa, was greater in harrowed area (97,1%) in relation to no harrowed area (92,5%) after one year of planting; and the survival of caroba, was 90% after one year of planting and showed no difference when compared the harrowed and no harrowed areas. The height and diameter of pau-de-balsa were greater in harrowed area after one year of planting, reaching 11.85 m and 11.42 cm, respectively. The differences occurred in caroba trees after the second year of planting, and reached, in the third year, 8.37 m of high and 11,18 cm in diameter. Besides other factors inherent to the species, the more friable soil of the harrowed area, facilitated higher growth to two studied species.
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