Relationship between wood density and alkaline copper quaternary (ACQ) preservative uptake in twenty lesser-known Sri Lankan timber species

Abstract

Wood is considered excellent, environmentally friendly green building material for furniture, interior decorations, and construction purposes. Storing atmospheric CO2 in wood can be an effective strategy for mitigating climate change. However, due to the limited availability of high grade timber resources, the market price of dominant species continues to rise, promoting the use of lesser-known timber species as alternatives. These species, like most timbers, are vulnerable to insect damage. Generally, wood deterioration in lesser-known species is caused by several factors, such as environmental and climatic conditions, as well as degradation agents like pests and insects. To prevent such damage, preservatives are applied to timber. However, some wood preservatives harm the environment and human health. As a solution, Alkaline Copper Quaternary (ACQ) has been introduced as an environmentally friendly wood preservative. Density is a key indicator of wood strength and is predictive of properties such as hardness, ease of machining, and nailing resistance. This study aimed to investigate the relationship between wood density and the chemical uptake of ACQ in twenty lesser-known Sri Lankan wood species treated using the dipping method for a 6-hour period. A negative relationship between chemical uptake and the density was observed (𝑅2 = 0.6463). Arawkeriya (38.82 kg/m3), Rukkattana (40.84 kg/m3), Katuboda (42.99 kg/m3), and Wanasapu (47.26 kg/m3) showed higher chemical penetration, while Pelan (26.95 kg/m3) and Mahanuga (29.92 kg/m3) showed moderate penetration. Diya Na (2.50 kg/m3), Dunumadala (3.14 kg/m3), Aladu (3.73 kg/m3), Path Kella (3.77 kg/m3) and Acasia (3.99 kg/m3) showed the lowest chemical penetration of the ACQ preservative.