天然松香有三种来源,质量最好的是脂松香。近年,美国脂松香产量,据称由于“劳力紧张”一再下跌。为了提高采脂工效,以维持生产,获取利润,美国普遍采用了涂抹硫酸膏的化学刺激采脂法,并在继续研究新的更为有效的化学刺激剂。据报道,1973年下半年,美国松香松 There are three natural rosin sources, the best quality is gum rosin. In recent years, the output of U.S. gum rosin is said to have fallen again and again due to “labor stress”. In order to enhance the work efficiency of lipid-collecting in order to maintain production and obtain profits, the United States generally adopts the chemical stimulation method of applying sulfuric-acid paste and continues to study new and more effective chemical stimulants. According to reports, the second half of 1973, the United States pine rosin