Simulating Changes in Organic Carbon of Forest Soils Due to Climate Change at Different Altitudes Using the Roth C Model

This study explores the influence of land altitude on soil organic carbon (SOC) storage in the forest soils of Talesh County, Gilan Province. Soil samples were collected from four distinct altitudinal ranges (500–1000, 1000–1500, 1500–2000, and 2000–2500 meters above sea level) with comparable intrinsic characteristics. Composite soil samples were taken from a depth of 0–35 cm, and the concentration of soil organic carbon, combined with soil bulk density from undisturbed samples, was used to calculate SOC stocks.Statistical comparisons were conducted using a randomized complete block design (RCBD). The Roth C model was employed to estimate the organic carbon content of the soils. Climatic data and soil organic carbon content at each altitude were utilized to calibrate and validate the model. To assess potential variations in SOC storage under changing conditions, diverse climate change scenarios were simulated using the Roth C model.The findings revealed that as land elevation increased, SOC storage also increased, primarily due to higher precipitation and lower temperatures at higher altitudes. The Roth C model demonstrated high precision in estimating SOC levels, with correlation and determination coefficients of 0.97 and 0.95, respectively.The model further suggested that under current climate conditions, soil organic carbon remains stable over time. At equilibrium, the carbon input into the soil through plant residues equals the carbon output from the soil as carbon gas emissions.