Integrated ecological and socioeconomic assessment of poplar cultivation using biometric and GIS data for sustainable management in Gilan Province, Iran

Poplar-based timber plantations are an important source of wood in Gilan Province, Iran; however, province-scale and georeferenced evidence integrating plantation extent, biometric characteristics, management indicators, and socioeconomic constraints has remained limited. This study combined a complete field inventory, systematic biometric measurement, geographic information system (GIS) analysis, and a specialist-based socioeconomic survey to assess poplar cultivation across the province. A complete inventory of 16,250 identified poplar plantation sections, covering 12,179 ha and comprising 13,861,723 trees, was conducted. From this inventory, 514,702 trees were systematically selected in proportion to plantation-section area for measurements of diameter at breast height (DBH), total height, and age. Sowme’eh Sara County contained the largest plantation area (6,944 ha), and the obtained provincial standing timber volume was 6.78 × 10⁶ m³. Robust county-level comparisons indicated substantial spatial heterogeneity in plantation-section area, tree age, DBH, total height, single-tree volume, tree number, and total section volume. The relative Forest Productivity Index (FPI) and Forest Management Efficiency (FME) indicator also varied among counties, with higher FPI values generally associated with older and larger trees. In the socioeconomic component, 320 valid specialist questionnaires were obtained through purposive sampling. The results identified land fragmentation, small landholdings, and market concentration among intermediaries as major perceived constraints on poplar plantation development. This study provides an integrated province-scale framework linking complete plantation-section inventory, biometric assessment, spatial analysis, relative productivity and management indicators, and stakeholder evidence for the evidence-based assessment of poplar plantations in Gilan Province.