Desenvolvimento de Khaya ivorensis a. chev (mogno-africano) sob diferentes espaçamentos de plantio.

Abstract

The objective of this study was to compare the growth, wood productivity per hectare and survival in Khaya ivorensis crops with different spacing, in the municipality of Igarapé-Açu, in the northeast region of Pará, on the Fattoria Piave property. The first chapter aimed at a bibliographic survey on the cultivation of the species in Brazil and in the world, to support the discussions of subsequent articles. The second chapter aimed to compare the growth, productivity and survival in Khaya ivorensis crops in 3 different spacing, called treatments T1 (5 x 3 m), T2 (4 x 4 m) and T3 (5 x 5 m). Dendrometric evaluations of total height and diameter at breast height (DAP) were performed on randomized trees, observing survival. Statistically, univariate analysis in subplots (F test) was applied as a function of time to analyze these 3 treatments, and their interactions in the ages. The averages of total height, DBH and volume per tree were compared using the Tukey test (p <0, 05) to verify whether the spacing differed as a function of time. Survival in treatments T1, T2 and T3 were obtained by recounting each planting. When comparing the averages, the height of trees that were 4 and 7 years old at T1 differed from treatments T2 and T3. Regarding the DAP at 7 years old, the highest DAP was registered in T3. Based on the volumetry per tree, the number of trees / ha, obtained for the 3 spacings at 7 years of age, were 132.38 m³ / ha in treatment T1, 98.49 m³ / ha in T2 and 130.06 m³ / ha in T3. The plant survival rate was not higher in treatment T3 (86.3%), followed by T2 (85.8%) and T1 (80.02%). It was concluded that the spacing influenced the development of Khaya ivorensis trees, and the 5x5 spacing showed better tree growth, with a higher percentage of survival, volumetry per plant and per hectare, demonstrating greater technical and economic viability among those evaluated. The third chapter aimed to analyze the growth, productivity and survival of a cultivation of Khaya ivorensis, in the 6 x 6 m spacing in a triangle, for 7 years of age. The collection of dendrometric and survival data was carried out annually in 4 fixed sample units for a period of 7 years. The volume per hectare of stem wood and the corresponding Current and Average Annual Increments were calculated. Data analysis was performed using ANOVA GLM, to better study the averages and growth trends for the different variables studied. As a result, it was possible to observe the satisfactory growth in the total and bole heights, similar to other crops registered in the bibliography about the species, with higher densities of population. For the DAP variable, a higher growth than that found in crops with higher densities was reported, except when compared to irrigated crops. The calculated productivity reached 51.38 m³ / ha in the 7th year, with current and average increasing increments until the 6th year of planting and the calculated survival reached an average of 86%. However, it was concluded that the planting of this species in wide spacing shows growth at satisfactory heights and DBH, except when attacked by pests that affect apical sprouting, reaching productivity similar to that obtained in crops with the species in higher densities and in comparison with other species noble in shorter spacing. Survival was satisfactory, and much of the reported mortality occurred due to factors unrelated to spacing.