Large scale spatial assessment, modelling and identification of drivers of soil respiration in the Western Himalayan temperate forest

Soil respiration (Rs) is a natural phenomenon of CO2 emission and has a significant contribution in regulating the carbon cycle. Identifying the drivers that influence soil CO2 emissions are essential for assessing the potential impacts of change on the Carbon (C) cycle in the forest ecosystem. The present study estimated soil respiration and evaluated different drivers i.e., soil, vegetation, climate, and topography by collecting data from twelve sites (forest sub-types) of temperate forests widely distributed in the Indian Western Himalayan Region. Total 432 observations were recorded from six individuals of two major tree species of twelve sites at three locations below the crown across the selected sites. ANOVA, Regression and Structural Equation Modelling (SEM) were used to analyze the data. No significant variance in Rs between the individual trees of the selected major species and between the major species of a site were observed, however, there was a significant difference between the sites for Rs. SEM of the temperate forest explains that various climatic (maximum and minimum temperature), vegetation (density and abundance) and topographical factors (altitude, longitude and latitude) were intricately related to the functioning of the temperate forests, however Rs was positively influenced by soil temperature, maximum air temperature, and altitude, and negatively by abundance. The study concludes that Rs varied differentially across the various forest sub-types of temperate forests and increases with increase in temperature and altitude. The results would provide information for estimating the feedback of the soil carbon fluxes to future climate change and also the development of carbon management policies for forest ecosystems.