现在在我们生产和使用的三种松香——浮油松香、木松香和脂松香中,浮油松香居领先地位。过去的十五年,美国这三种松香的生产水平发生了很大的变化:1981年脂松香产量只有1967年的1/10;木松香不到1967年的一半;只有浮油松香增产。美国脂松香生产平稳地下降,部分是由美国东南部的经济和人口变化引起的。其它发达国家情况 Now, among the three types of rosin we produced and used, floating oil rosin, wood rosin and gum rosin, floating oil rosin dominates. In the past fifteen years, the level of production of these three types of rosin in the United States has undergone major changes: In 1981, the production of gum rosin was only 1/10 of that in 1967; wood rosin was less than half of that in 1967; only oil-based rosin increased production. The production of gum rosin in the United States has been steadily declining, partly due to economic and demographic changes in the southeastern United States. Other developed countries