Understanding how tree individuals allocate whole-tree total nonstructural carbohydrate (NSC) between growth and storage is key to reveal the response of altitudinal treeline to climate warming. Yet, modellings of total carbon allocation currently ignore local adaptation under cold stress. We used a reciprocal transplant experiment and an experimental warming treatment to identify whether low temperature causes genetic differentiation in treeline species Larix chinensis. The results show that the ratio of nonstructural carbohydrate storage to growth (R-value) which presents an explicit C-based tradeoff of growth-storage is influenced neither by adaptation nor by plasticity. High-elevation trees require a stable proportion of NSC storage to maintain survival, leading to convergence in R-value, while the low-elevation populations show stronger co-gradient plasticity. Warming does not eliminate the advantage of local adaptation in the proportion of NSC storage, supporting the perspective that cold-adapted edge populations do not change heritable variation in carbon allocation under climate warming.