Indonesia is home to an abundance of natural resources, including a large number of tree species, with the Forestry Research and Development Agency listing 4000 species of trees. Although the use of forestry resources has traditionally focused on wood, there are other materials in wood that can be extracted using solvents that do not damage the structure of cellulose or lignin. These materials are called extractives and include tannins, dyes, essential oils, resins, waxes, sap, and starch. The amount of extractive substances in wood ranges from less than 1% to over 30%, depending on various factors related to tree growth and the season in which the tree is harvested. Extractive substances affect wood properties such as color, odor, taste, resistance to microorganism attack, density, hygroscopicity, and combustibility.
Extractives substances are divided into two groups, those stored in capillary structures and those stored in cell wall structures. One type of wood that is considered problematic due to its high extractive content is Keruing wood (Dipterocarpus spp.), which is often limited to wood use only. However, there are many species of oily Keruing that contain high oils, which is why they are limited in use. An anatomical analysis is necessary to effectively differentiate between species, as each species has unique characteristics.
The solubility value of the Keruing wood studied was more than 4%, indicating that it had a high extractive content. However, the specific substance present was not identified. In general, the content of extractive substances in wood varies from 2-10% in non-tropical wood and can reach up to 20-25% in some types of tropical wood. Extractive substances are typically divided into three subgroups: aliphatic groups, terpenes and terpenoids, and phenolics.
In conclusion, there is a great opportunity to optimize the use of natural resources in Indonesia by using extractives found in wood species, including those with high extractive content such as Keruing wood. An anatomical analysis is necessary to differentiate between species effectively. Identifying the specific substance present in extractives can provide more value to the use of wood species in various industries.
Jamaludin Malik and Adi Santoso 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1034012149