Publication Output and Internationalization Among a Defined Population of Italian Forest Researchers: A Bibliometric Assessment, 2013–2025

National bibliometric assessments can show how scientific communities change, but their results depend strongly on how the researcher population is defined. This paper assessed publication output, citation patterns, institutional structure, and collaboration for a defined Italian forest research population. Population identification was completed in February–March 2026 by combining a Scopus-derived researcher database with the official 2025 Ministry of University and Research staff lists for the relevant forest disciplines. The final study population comprised 250 researchers. All Scopus-indexed publications associated with these author IDs during 2013–2025 were retrieved through the Scopus API in June 2026; the primary corpus was not restricted by forest-topic screening. The corpus contained 9918 unique publications. Annual output associated with the study population increased from 449 publications in 2013 to 971 in 2025, while publication-active researchers increased from 148 to 236. Mean fractional output per active researcher increased from 3.13 publications per year in 2013–2015 to 4.08 in 2023–2025. A persistent-author subset of 188 researchers observed in both periods also exhibited higher late-period output, indicating that recent entry alone did not account for the increase. Internationally co-authored publications increased from 38.7% to 60.7%, and the top 10% of publications received 52.4% of all citations. A conservative title/source forest-signal subset reproduced the increasing output pattern. The results refer to the defined end-of-period study population rather than to a complete historical census, but provide a documented basis for future monitoring.