Contrasting restoration strategies shape tree carbon recovery through different ecological pathways in subalpine forests

Abstract Forest restoration is a major strategy for rebuilding forest carbon stocks, but similar gains in total tree carbon may arise from different ecological pathways. Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) trees differ in resource‐use strategies, nutrient economies and carbon allocation patterns, yet it remains unclear whether passive and active restoration lead to tree carbon recovery through similar or contrasting changes in AM‐ and EcM‐associated tree carbon stocks. We compared tree carbon stock between secondary forests (SF) and planted forests (PF) across a recovery chronosequence in subalpine forests. By separating total above‐ground tree carbon into EcM and AM components, and integrating mycorrhizal dominance, functional diversity, functional composition, stand structural complexity and soil variables, we examined how restoration strategy and recovery stage jointly shaped tree carbon recovery. Restoration strategy did not significantly alter the overall recovery trajectory of total tree above‐ground carbon, but it changed how carbon was distributed among mycorrhizal tree groups. Total and EcM‐associated carbon stocks increased with recovery stage in both SF and PF, with no restoration strategy × recovery stage interaction for total carbon ( p = 0.567) or EcM‐associated carbon ( p = 0.283). By contrast, AM‐associated carbon showed a significant restoration strategy × recovery stage interaction ( p = 0.005). Mycorrhizal dominance also shifted differently between the two strategies. In SF, variation in carbon stocks was more closely associated with mycorrhizal dominance and functional reassembly, whereas in PF, it was more strongly related to stand structural complexity and soil conditions. Structural equation models supported these strategy‐specific pathways, showing that recovery stage promoted carbon accumulation through different indirect pathways under the two restoration strategies. Synthesis and applications . Our results highlight that the overall trajectory of total tree carbon recovery can remain broadly similar even when the underlying ecological pathways differ markedly between restoration strategies. Restoration success should therefore be evaluated not only by total tree carbon but also by mycorrhizal composition, stand structural complexity and soil‐related constraints on carbon recovery. This study provides a more mechanistic basis for evaluating and managing forest restoration for carbon sequestration.