Bioenergetic use of Araucaria angustifolia branches

Highlights: • A. angustifolia branches shown desirable energy characteristics for energy generation. • A. angustifolia branches evaluated showed calorific value suitable for use as energy-generating biomass. • The results obtained here encourage new studies and shown a A. angustifolia branches as an energetic and ecological option. • A. angustifolia branches (coproduct) shown higher calorific value even when compared with wood of stem. • A. angustifolia branches biomass can become an important ally for species conservation as a coproduct. The aim of this study was to physically, chemically and energetically characterize A. angustifolia branches of different dimensions and to compare them with the values described in literature. Thus, a total of 30 branches from 15 adult native trees were divided into three treatments according to the following base diameters: (S) less than 0.06 m, (M) between 0.06 and 0.10 m; and (L) greater than 0.10 m. A. angustifolia branches of all dimensions presented desirable bioenergetic characteristics with high calorific value, low ash content, volatile material content and adequate fixed carbon. Basic density was 470.18 kg m⁻³, fixed carbon and volatile content showed a significant difference between L and S classes. Ash content was close to 1.0%. Gross calorific value showed an average of 4,743.3 kcal kg⁻¹. In comparison with the data found in the literature, A. angustifolia branches presented superior energetic qualities to several forest species woods traditionally used as bioenergy. The results obtained herein demonstrate the energetic potential of A. angustifolia branches for energy generation and encourage studies on this co-product as a profitable and ecological option as it does not need to cut the tree, and may contribute to species conservation.