Effects of plant spacing on the physical, chemical and energy properties of eucalyptus wood and bark

Abstract

Plant spacing affects tree growth and, consequently, the properties of its wood. However, not much is known about how plant spacing influences changes in wood properties. The aim of this study was to evaluate the influence of plant spacing on wood density as well as chemical and energy properties in Eucalyptus wood and bark. Clones of Eucalyptus grandis × E. camaldulensis were grown in five different plant spacings, namely, 1.5, 3.0, 4.5, 6.0 and 9.0 m² (representing 3.0 m × 0.5 m, 3.0 m × 1.0 m, 3.0 m × 1.5 m, 3.0 m × 2.0 m and 3.0 m × 3.0 m respectively) in Itamarandiba, northern Minas Gérais, Brazil. The findings indicated that plant spacings significantly influence key properties of wood and bark. Trees planted at 4.5 to 9.0 m² spacings had wood density approximately 8% higher than the same clones planted in narrow spacing (1.5 m²). Lignin content from wood of 6.0 and 9.0 m² spacing was approximately 12% higher than wood from 3.0 m² spacing. The holocellulose was also affected by plant density. However, extractives and insoluble lignin contents did not vary according to the plant spacing. This study showed that, for Eucalyptus clones in this region, plantations with wider spacing could lead to production of raw materials with characteristics more suitable for energy purposes.