Dynamics of resin yield in Pinus brutia: A quantitative analysis using bark streak tapping

The sustainable harvesting of resin yield from forests plays a crucial role in providing valuable renewable resources. Specifically, Pinus brutia forests in Türkiye are significant for their oleoresin, utilized in various industries. Yet, understanding how dendrometric and meteorological factors influence resin yield is essential for optimizing production while ensuring forest sustainability. This study aimed to estimate oleoresin yield in Pinus brutia plantations using dendrometric parameters (such as diameter at breast height and tree height, basal area, volume and canopy closure) and meteorological parameters (including monthly; minimum, maximum, and average temperature, precipitation, humidity, vapor pressure, and wind speed), to identify the key factors affecting resin production. Resin was collected from 389 Pinus brutia trees of varying diameters across 27 different plots using the bark streak tapping method, with data recorded every 15 days over a year. Weighted Leased Square regression analysis was conducted to explore the relationship between resin yield and the aforementioned dendrometric and meteorological parameters. The analysis revealed that diameter at breast height, monthly average temperature, wind speed, and precipitation significantly influence resin yield. The study underscores the intricate interplay between these factors and resin production, indicating that larger diameters and specific meteorological conditions—especially average temperature, wind speed, and precipitation—are positively correlated with increased resin output. The findings suggest that sustainable resin extraction practices in Pinus brutia forests should account for not only the physical characteristics of the trees but also the local meteorological conditions to maximize yield without compromising forest health. This research contributes to the development of more effective guidelines for oleoresin harvesting, ensuring both economic viability and ecological preservation.