Interest in the dynamics of soil respiration (Rs) in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes. However, as a principal silvicultural practice, the long-term impacts of thinning on Rs and its heterotrophic and autotrophic respiration components (Rh and Ra, respectively) in subalpine plantations are poorly understood, especially in winter. A 3-year field observation was carried out with consideration of winter CO2 efflux in middle-aged subalpine spruce plantations in northwestern China. A trenching method was used to explore the long-term impacts of thinning on Rs, Rh and Ra. Seventeen years after thinning, mean annual Rs, Rh and Ra increased, while the contribution of Rh to Rs decreased with thinning intensity. Thinning significantly decreased winter Rs because of the reduction in Rh but had no significant effect on Ra. The temperature sensitivity (Q10) of Rh and Ra also increased with thinning intensity, with lower Q10 values for Rh (2.1-2.6) than for Ra (2.4-2.8). The results revealed the explanatory variables and pathways related to Rh and Ra dynamics. Thinning increased soil moisture and nitrate nitrogen (NO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{3}<^>{ - }$$\end{document}-N), and the enhanced nitrogen and water availability promoted Rh and Ra by improving fine root biomass and microbial activity. Our results highlight the positive roles of NO3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{3}<^>{ - }$$\end{document}-N in stimulating Rs components following long-term thinning. Therefore, applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO2 emissions. The increased Q10 values of Rs components indicate that a large increase in soil CO2 emissions would be expected following thinning because of more pronounced climate warming in alpine regions.