**2. Data and Methods**

### *2.1. Literature Collection*

In the core database of the Web of Science (WOS) Science Citation Index (SCIE), a search for literature between 1981 and 2022 with a subject term of "Alnus nepalensis\*" yielded a total of 140 records. In the China National Knowledge Infrastructure (CNKI) database, with the subject terms "Nepalese alder", "Handonggua", or "Mengzi alder", we found a total of 366 records. After manually removing impurities from the search data such as patents, reports, notices, and other documents, as well as some of the "Handonggua" literature which documented other alder species rather than *Alnus nepalensis*, 128 English papers and 334 Chinese documents were finally obtained.
