Resin tapping in Masson pine (Pinus massoniana): Response of resin yield and its product quality to film mulching and chemical stimulation treatments

Abstract

Pine resin, a valuable bio-based resource with diverse applications, holds significant economic potential in China due to the abundance of Masson pine (Pinus massoniana). In order to maximize the value of pine resin, it is essential to focus on the rational tapping of pine trees. However, the traditional method for resin tapping employs an open system where the wounds, the resin ducts and the collected resin remain exposed to environmental factors such as rain and sunshine. Thus, turpentine components may volatilize, affecting both composition of turpentine and the quality of rosin. In this study, the treatment of film mulching (FM) to establish closed tapping conditions, and without film mulching but spraying with ethephon (WFE), along with their combination, both film mulching and spraying with ethephon (FME) were introduced. The result showed that resin yields were increased in all treatments, with FM and WME showing relatively similar in resin yield. The FME treatment achieved the highest resin yield (115.77 % increase) and the largest effect size (η² = 0.723) when resin was collected every eight days. If a national extension is realized, there may be an additional revenue of 735,03.8 million CNY per year. Gas chromatography (GC) analysis revealed that FM and FME treatments effectively inhibited the volatilization of the main turpentine composition, maintaining higher α-pinene and β-pinene content. The color of rosin was measured using a colorimeter and assessed for quality, and the film mulching treatment significantly improved the rosin color compared to without mulching. Ethephon application enhanced resin yield by stimulating the secretion of pine resin ducts, but the quality of pine resin and rosin was not substantially improved. In the FME group, which combined the advantages of both methods, resin yield was substantially increased, and the quality of resin and rosin was improved. In this study, an efficient and practical tapping method was proposed in terms of both chemical stimulation and physical protection.