Crescimento e produtividade de clones de eucalipto sob diferentes espaçamentos em Macaíba-RN

Abstract

Silviculture is a widely known and practiced activity throughout Brazil, with emphasis on eucalyptus cultivation. The objective of this study was to evaluate the growth and productivity of two eucalyptus clones under different planting spacings, at Sítio São Clemente located in the rural area of ​​the municipality of Macaíba-RN. The treatments studied were two clones of the same genetic origin being called (Urograndis A08 and EUACA105) and four planting spacings (1.25 x 9 m; 1.5 x 9 m; 2 x 9 m and 2.5 x 9 m) in a plantation with 24 months of age. The first growth assessment was performed at 24 months of age (measurement of stem diameter and total height), the second at 48 months (diameter at breast height, total height, and the third at 66 months (diameter at breast height, total height). The planting system was an Integrated Crop-Livestock-Forestry (ILPF) system in four spatial arrangements: 1.25 x 9 m; 1.5 x 9 m; 2 x 9 m and 2.5 x 9 m, integrated between the rows cassava (Manihot esculenta) and pangolão grass (Digitaria eriantha). The productivity variables analyzed were volume of wood produced and Average Annual Increment (IMA) and Current Annual Increment (ICA). The design used was randomized blocks in a 2x4 factorial arrangement with two clones and four spacings. The means of each variable were analyzed using the Bioestat 5.3 software. The growth in total height of the two clones Eucalyptus urograndis and EUACA105), both at 24, 48 and 66 months, did not differ between spacings. The diameter at breast height was greater in the less dense spacings, while the volume did not present any change according to the spacings evaluated. In relation to the ICA and IMA variables, the EUACA105 clone presented greater results in relation to Urograndis A08 among all the spacings evaluated. It is concluded that eucalyptus is a promising crop for the region, being recommended for the replacement of wood from native trees, both in the sustainable and economic aspects.