Enriquecimento de florestas secundárias com Schizolobium parahyba var. amazonicum (Huber x Ducke) Barneby e Hymenaea courbaril L. submetidos à adubação em clareiras artificiais, município de Igarapé Açu, PA.

Abstract

Considering that the forest undergoes a slow recovery process after logging activities, it is necessary to apply silvicultural treatments that stimulate the recovery of those areas. Therefore, this study aimed to evaluate the survival and growth of Paricá and Jatobá seedlings submitted to fertilization and planted in artificial canopy openings of a secondary forest in Igarapé-Açu, PA. The study was conducted at Fattoria Piave, municipality of Igarapé-Açu, PA. Seven canopy gaps were opened where 101 Paricá seedlings and 101 Jatobá seedlings were planted, fertilized and non-fertilized. Six measurements were made, and the following parameters were evaluated: height, individual's situation, incident sunlight, and presence of vine. Afterwards, survival rate, growth, evaluated by the Periodic Monthly Increment in Height (IPMh), and height were calculated. To evaluate the survival and growth of the species, a completely randomized design was used with repeated measurements over time in a 2x6 factorial scheme where the factors were: fertilization of seedlings (fertilized and non-fertilized) and time measurements (1, 2, 5, 14 and 20 months). Moreover, regression analysis was applied as well as the correlation between the levels of incident sunlight, height, and IPMh tested by Spearman's correlation test. For Jatobá, survival rate ranged from 100% and 94%, with no effect of the interaction between fertilization and the days evaluated for height and IPMh. Just as there was no correlation between the levels of incident sunlight and height and with the IPMh, in the evaluated period. For Paricá, survival varied between 100% and 94%. There was an interaction effect between fertilization and the days evaluated for height and IPMh. However, there was no correlation between the levels of incident sunlight and height as well as with IPMh, in the evaluated period. High survival rates were found for both species; however, Paricá was the species that showed the best response in terms of growth under fertilization conditions. Therefore, it is the most suitable species for the forest ecosystem restoration in a shorter time, considering its excellent growth in height in these conditions.