Characteristics of carbon storage variations of Quercus mongolica forests at different development stages in the east of Liaoning mountainous area and their influencing factors

To explore the changing patterns of carbon storage at different development stages of forest stands, identify the factors influencing carbon storage, and to provide a theoretical foundation for the scientific management, operation, and enhancement of forest carbon storage.

Focusing on Quercus mongolica forests in the east of Liaoning mountainous area, the carbon storage in the arboreal layer was estimated using the anisotropic growth equation. Additionally, the carbon stocks of shrubs, herbs, litter, and soil within representative sample plots were measured utilizing the sampling method. Our analysis of these data elucidated the characteristics of ecosystem carbon storage across different developmental stages of Q. mongolica forests. Moreover, redundancy analysis was employed to identify the key environmental factors influencing variations in carbon storage.

1) The ecosystem carbon storage of Q. mongolica forests in the east of Liaoning mountainous area is 296.13, 332.65, 300.72, and 503.55 t·hm^-2 for young, half-mature, mature, and overmature forests, respectively. Notably, overmature forests exhibit the highest carbon stocks, significantly surpassing those of the other developmental stages. (P<0.05); 2) Among the ecosystem components, the carbon stock in the soil layer (0-30 cm) accounted for the largest proportion. As the forest progresses through its developmental stages, carbon storage in the vegetation layer gradually increases, while the proportion of soil carbon stock decreases; however, it consistently remains above 50%; 3) The proportion of carbon storage in the vegetation layer exhibits a trend of initially increasing and then decreasing with forest age, reaching its maximum of 48% in mature forests; 4) Elevation, aspect, and soil total phosphorus content are the primary environmental factors influencing variations in carbon storage, collectively accounting for 20.5%, 12.1%, and 3.6% of the total variation in ecosystem carbon storage, respectively.

Among the various development stages of Q. mongolica forests in the east of Liaoning mountainous area, carbon storage remains relatively stable from the young to mature stages, while overmature forests exhibit the highest ecosystem carbon stocks. The soil layer constitutes the primary component of carbon storage within the ecosystem, followed by the vegetation layer. Elevation is the most significant factor influencing changes in ecosystem carbon storage, followed by aspect and total phosphorus content in the soil.