The Effectiveness of Various Natural Preservatives on the Prevention of Decomposition in Balsa Wood

This experiment was conducted to determine a natural wood preservative that was effective in preventing wood decay. Wooden structures are treated with chemical wood preservatives that prevent decomposition caused by microbial agents. The results of this experiment are beneficial to the lumber industry and consumers because the leading chemical wood preservative, Chromated Copper Arsenate (CCA), contains carcinogenic arsenic that can lead to serious health issues ("BANCCA.ORG- Health Hazards of CCA, Arsenic & Chromium”).

Four natural preservatives—lemon juice, vinegar, sucrose, and sodium chloride—chosen based upon their effectiveness in food preservation, were tested along with a water control group. For each preservative, a sample of five balsa wood samples was used. These wood samples were pressure treated with the preservative and with a chemical stump remover. This stump remover provided nutrients for the fungus that causes rotting, facilitating decomposition. A humidifier was used to create the moist environment that fosters the initial growth of the fungus. After three days, the tensile strength of each wood sample was tested. There was an inverse relationship between the tensile strength of the wood samples and the magnitude of wood decay. An ANOVA test was conducted, and it was determined that not all of the preservatives retained equal average masses. The lemon juice and vinegar preservatives resulted in the greatest tensile strength. The acidity of these preservatives breaks down the cell structures of the microbial agents that cause decomposition. Consequently, lemon juice and vinegar were most effective in preventing wood decay.

Research Done By:

Rasika Patil
Sterling Heights High School

Claire Wells
Sterling Heights High School