国外森林鼠害研究起步较早，１９世纪中叶北欧一些国家已对林鼠的危害及主要害鼠的生物学进行了观察和研究。２０世纪以来，北欧、美国、加拿大、日本等国家和地区针对森林鼠害及其的防治开展了一系列多学科研究工作。１　主要害鼠及危害的主要树种欧洲森林害鼠分布有三种情况? Foreign studies on forest rodent pests started earlier. In the mid-19th century, some countries in North Europe have already done some observations and studies on the harm of rodents and the biology of the major pests. Since the 20th century, North Europe, the United States, Canada, Japan and other countries and regions have carried out a series of multidisciplinary research on forest rodent pests and their prevention and treatment. 1 main pest rats and the main species of harm European forest pest distribution in three cases?