Acid deposition is a major biogeochemical driver in forest ecosystems, but the impacts of long‐term changes in deposition on forest productivity remain unclear. Using a combination of tree ring and forest inventory data, we examined tree growth and climate sensitivity in response to 26 years of whole‐watershed ammonium sulfate ((NH₄)₂SO₄) additions at the Fernow Experimental Forest (West Virginia, USA). Linear mixed effects models revealed species‐specific responses to both treatment and hydroclimate variables. When controlling for environmental covariates, growth of northern red oak (Quercus rubra ), red maple (Acer rubrum ), and tulip poplar (Liriodendron tulipifera ) was greater (40%, 52%, and 42%, respectively) in the control watershed compared to the treated watershed, but there was no difference in black cherry (Prunus serotina ). Stem growth was generally positively associated with growing season water availability and spring temperature and negatively associated with vapor pressure deficit. Sensitivity of northern red oak, red maple, and tulip poplar growth to water availability was greater in the control watershed, suggesting that acidification treatment has altered tree response to climate. Results indicate that chronic acid deposition may reduce both forest growth and climate sensitivity, with potentially significant implications for forest carbon and water cycling in deposition‐affected regions.

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评估长期流域酸化试验对温带森林生长和气候敏感性的影响

酸沉积是森林生态系统中的主要生物地球化学驱动力，但沉积的长期变化对森林生产力的影响尚不清楚。我们结合树木年轮和森林清单数据，研究了在Fernow实验森林（美国西弗吉尼亚州）添加了26年的全流域硫酸铵（（NH ₄）₂ SO ₄）后，树木的生长和气候敏感性。。线性混合效应模型揭示了对处理和水文气候变量的物种特异性反应。当控制环境协变量时，北部赤栎（Quercus rubra），红枫（Acer rubrum）和郁金香杨（Liriodendron tulipifera）的生长）与处理过的分水岭相比，对照分水岭的）更大（分别为40％，52％和42％），但黑樱桃（樱桃李）没有差异。茎的生长通常与生长季节的可用水量和春季温度成正相关，而与蒸汽压缺乏成负相关。在对照流域中，北部红橡树，红枫树和郁金香杨树的生长对水分利用的敏感性更高，这表明酸化处理改变了树木对气候的响应。结果表明，长期的酸沉降可能会降低森林的生长速度和对气候的敏感性，这可能会对受沉积影响地区的森林碳和水循环产生重大影响。