Papermaking Potential of

Lophostemon suaveolens is a tree species capable of growing in marginal environments, including peatland ecosystems. This study evaluated the wood, pulp and handsheet properties of L. suaveolens as a potential raw material for pulp and paper production. Two 4-year-old trees grown in peatland plantations at Riau Province, Indonesia were sampled. Kraft pulping was conducted at 25% sulfidity,a wood chip to liquor ratio of 1:4; a maximum cooking temperature of 170°C, and a cooking time of 2 hours at the maximum temperature. Active alkali concentrations of 14%, 16%, 18%, 20% and 22% were tested. For handsheet preparation, pulp obtained from the 20 and 22% active alkali treatments were refined at beating times of 0, 10, 20, 30, and 40 min. The chemical characteristics and specific gravity (0.58) of L. suaveolens wood indicated its suitability as a raw material for papermaking. However, the fiber dimensions suggested relatively low fiber quality according to the Indonesian wood fiber quality classification system. Kraft pulping produced screened yields ranging from 27% to 51% and kappa numbers from 17.33 to 51.31. The black liquor exhibited total solids contents of 18.44–23.01 g L−1, pH values of 11.33−12.79, and residual active alkali concentrations of 0.60–10.46 g L−1. Handsheet properties included burst indices of 0.27–2.33 kPa•m2 g−1, tear indices of 2.16–4.58 mN•m2 g−1, tensile indices of 5.33–36.13 N•m g–1, and brightness values of 14.59–24.59%. The optimum treatment combination for producing high-quality pulp and paper was obtained at an active alkali concentration of 20% and a beating degree of 315 mL CSF, corresponding to 20 min of beating.