As the climate changes, warmer spring temperatures are causing earlier leaf-out^1,2,3 and commencement of CO₂ uptake^1,3 in temperate deciduous forests, resulting in a tendency towards increased growing season length³ and annual CO₂ uptake^1,3,4,5,6,7. However, less is known about how spring temperatures affect tree stem growth^8,9, which sequesters carbon in wood that has a long residence time in the ecosystem^10,11. Here we show that warmer spring temperatures shifted stem diameter growth of deciduous trees earlier but had no consistent effect on peak growing season length, maximum growth rates, or annual growth, using dendrometer band measurements from 440 trees across two forests. The latter finding was confirmed on the centennial scale by 207 tree-ring chronologies from 108 forests across eastern North America, where annual ring width was far more sensitive to temperatures during the peak growing season than in the spring. These findings imply that any extra CO₂ uptake in years with warmer spring temperatures^4,5 does not significantly contribute to increased sequestration in long-lived woody stem biomass. Rather, contradicting projections from global carbon cycle models^1,12, our empirical results imply that warming spring temperatures are unlikely to increase woody productivity enough to strengthen the long-term CO₂ sink of temperate deciduous forests.

随着气候的变化，春季气温升高导致温带落叶林早叶^1,2,3和 CO ₂吸收^{1,3的开始，导致生长季节长度3}和年度 CO ₂吸收¹增加的趋势， ^3,4,5,6,7。然而，人们对春季温度如何影响树干生长^{8,9 知之甚少}，这会隔离在生态系统中停留时间较长的木材中的碳^10,11. 在这里，我们使用来自两片森林的 440 棵树的树木测量仪波段测量结果表明，春季温度升高会更早地改变落叶树的茎直径生长，但对生长高峰季节长度、最大生长速率或年生长没有一致的影响。北美东部 108 座森林的 207 个树木年轮年表在百年尺度上证实了后者的发现，那里的年轮宽度在生长旺季对温度的敏感程度远高于春季。这些发现表明，在春季气温升高的年份^{4,5任何额外的 CO} ₂吸收都不会显着促进长寿命木本茎生物质的封存。相反，与全球碳循环模型的预测相矛盾^1,12，我们的实证结果表明，春季气温升高不太可能增加足以增强温带落叶林长期 CO _{2汇的木本生产力。}