The aim of this work was to evaluate the silvicultural performance of a clone of Eucalyptus grandis x E. camaldulensis in different spatial arrangements in integrated farm system with crops and pastures in the southern State of Maranhão for energy (firewood). The test was conducted at the Santa Luzia, in the municipality of São Raimundo das Mangabeiras / MA. The experimental design was in randomized blocks, with three replicates and five treatments. The treatments consisted of five spacings with quintuplets rows: (3 m x 2 m) +14 m; (3 m x 1.5 m) +14 m; (1.5 m x 1.5 m) +14 m and triple rows: (3 m x 2 m) +14 m; (1.5 m x 1.5 m) +14 m. At 92 months of age were evaluated circumference at breast height (CBH) of plants and cubed 29 trees by the destructive method and adjusted the taper equations for calculating the form factor in different spatial arrangements to obtain the volume (m³) of wood per hectare per tree total height (m) and commercial (m), mean annual increment (IMA) and carbon accumulation (tCO2) in stem per hectare. The data were submitted to analysis of variance, and means were compared by Tukey test at 1% probability. The larger diameters and average heights were obtained in the treatments with quintuple row (3 m x 2 m) +14 m, Quintuple row (3 m x 2 m) +14 m and triple row: (3 m x 2 m ) +14 m. The first three spacings and the last in this test are economically viable according to economic indicators for the case study: internal rate of return (IRR) and net present value (NPV). Treatment with spatial arrangement (quintuplets rows with 3 m x 1.5 m + 14 m) with 92 months provides greater volume per hectare, annual increment, carbon accumulation (tCO2) in stem per hectare and increased economic results without practice thinning in this study.
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