Seasonal and Cyclical Fluctuations in Türkiye’s Veneer Sheets and Wood-Based Panels Production: Evidence from the 2005-2024 Period

Aim of study: This study investigates the temporal structure of Türkiye's wood-based panel and veneer production from 2005 through 2024 to explain how climatic seasonality along with the macro-economic shocks jointly shape industrial output. Moreover, it aims to establish whether environmental cycles or economic disturbances dominate in driving fluctuations and describe the degree of robustness and structural stability within the essential wood panel industry that forms part of its wood-based manufacturing system. Material and method: The analysis, based on monthly Eurostat production indices, applies a multi stage methodology combining classical and modern time-series tools. STL decomposes the time series to identify seasonal variations while the HP filter captures mid-range cyclical movements. YoY analysis measure short-term momentum and volatility, and a SARIMA model generates a 12-month forecast for 2025, integrating historical seasonality into the projection. Main results: The STL results show a consistent and regular seasonal pattern, with production peaking between May and August and declining between December and February, with an amplitude of approximately ±8 index points. Three major setbacks, the global financial crisis in 2009, the exchange-rate shock in 2018, and the pandemic in 2020, are identified by the HP-filtered cycle, followed by rapid recoveries, indicating adaptive capacity. YoY growth analysis shows that volatility has steadily declined over time, consistent with increasing structural stability and operational efficiency. The SARIMA forecast for 2025 suggests continued stabilization, with only mild mid-year softening and no indication of a pronounced cyclical downturn within the forecast horizon. Quantitatively, the HP-filtered cycle reaches troughs of about -7 (2009), -4.8 (2018), and -6.1 (2020) index points, and the SARIMA projection for 2025 implies moderate uncertainty with 95% prediction intervals of roughly ±4-6 index points. Research highlights: The wood-based panel industry in Türkiye has been reshaped into a robust and seasonally structured production system, in which planning is increasingly dependent on foreseeable seasonal cycles rather than being reactive to systemic shocks. This study establishes a reproducible analytical model to quantify industrial robustness and cyclical stability in emerging bio-based economies by integrating STL, HP, YoY and SARIMA within a combined time series framework.