Change in Doctoral Dissertation Topics in Forest Resources from U.S. Universities over Four Decades
Changes in forest resources expertise from 1978 to 2017, as measured by annual number of doctoral dissertations published on twenty topics, were examined. Using the ProQuest Dissertations and Theses Global database, titles and abstracts from 11,530 dissertations produced by fifty-six universities in the United States were selected. Automated content analysis and latent Dirichlet allocation were used to identify the optimal number of topic groupings among 7,742 dissertations that met selection criteria. Substantial differences were found in the pattern of publication among the twenty topics over time. The number of dissertations related to forest growth and silviculture; tree seedling propagation, physiology, and regeneration; and forest soil nutrients, ecology, and management declined over the past two decades. Dissertations related to forest wildlife management, including terrestrial wildlife ecology and management; wildlife food and nutrition; and fish ecology and management also declined during the same period. The number of dissertations in the fields of forest policy, politics, and social science; forest modeling, biometrics, and statistics; wood science; forest vegetation ecology; and avian ecology increased during the four decades. Dissertations published in the fields of forest economics, and forest entomology and pathology, remained relatively stable.
Study Implications: We found decreasing production of doctoral dissertations focused on applied forest and wildlife management topics in recent decades. Declining doctoral-level expertise in applied fields after the early 2000s suggest that there may be reduced capacity to address practical problems facing both forest and wildlife managers. This decline also suggests that finding university instructors qualified to teach more applied forest and wildlife courses may have been more difficult over the past decade and possibly into the future. Our analysis indicated that the increased number of dissertations in adjacent sciences supporting forest resources has substantially increased capacity in these areas.