1. The negative impacts of drought on forest growth and productivity last for several years generating legacies, although the factors that determine why such legacies vary across sites and tree species remain unclear.
2. We used an extensive network of tree‐ring width (RWI, ring‐width index) records of 16 tree species from 567 forests, and high‐resolution climate and normalized difference vegetation index (NDVI) datasets across Spain during the common period 1982‒2008 to test the hypothesis that climate conditions and growth features modulate legacy effects of drought on forests. Legacy effects of drought were calculated as the differences between detrended‐only RWI and NDVI series (i.e. after removing long‐term growth trends) and pre‐whitened RWI and NDVI series predicted by a model including drought intensity. Superposed Epoch Analysis (SEA) was used to estimate whether legacy effects differed from random. Finally, legacy effects were related to water balance, growth persistence and variability, and tree species identity.
3. We found a widespread occurrence of drought legacy effects on both RWI and NDVI, but they were seldom significant. According to SEA, first‐year drought legacies were negative and different from random in 9% and 5% of the RWI and NDVI series respectively. The number of significant second‐ and third‐year legacies was substantially lower. Differences between RWI and NDVI legacies indicate that canopy greenness and radial growth responses to drought are decoupled. We found variations in legacies between tree species with gymnosperms presenting larger first‐year drought legacies than angiosperms, which were exposed to less severe droughts. Greater growth variability can explain the presence of first‐year RWI legacies in gymnosperms from dry sites despite that the relationship between growth variability and legacies was complex.
4. Synthesis. Accounting for species and site responses to drought provides a better understanding of the magnitude and duration of drought legacies on forest growth and productivity. Despite the widespread occurrence of growth reductions in the years during and after drought occurrence, significant legacies were not very common, mostly lasted one year, and were more widespread in gymnosperms. These are relevant factors to be considered in the future when studying the consequences of drought on forest productivity and tree growth.

中文翻译：

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干旱遗产很短，在干燥的针叶林中盛行，并取决于生长变异性

1. 干旱对森林生长和生产力的负面影响持续了数年，从而产生了遗产，尽管尚不清楚为什么这些遗产在不同地点和树木之间变化的原因。
2. 我们使用了广泛的树轮宽度记录（RWI，环宽度指数）记录，记录了567‒森林中16种树种，以及1982-2008年整个共同时期西班牙的高分辨率气候和归一化植被指数（NDVI）数据集检验以下假设：气候条件和生长特征会调节干旱对森林的遗留影响。干旱的遗留效应计算为仅趋势下降的RWI和NDVI系列之间的差异（即，去除了长期增长趋势之后）与通过包括干旱强度的模型预测的预增白的RWI和NDVI系列之间的差异。叠加时代分析（SEA）用于估计遗留效应是否不同于随机效应。最后，遗留效应与水的平衡，生长的持久性和变异性以及树木的种类有关。
3. 我们发现干旱遗留对RWI和NDVI的影响普遍存在，但很少引起重大影响。根据SEA，RWI和NDVI系列的第一年干旱遗存为负值，分别为9％和5％，与随机值不同。第二年和第三年的重要遗产数量大大减少。RWI和NDVI遗产之间的差异表明，冠层的绿色度和干旱引起的径向生长响应是分离的。我们发现，裸子植物在第一年的干旱遗留物要比被子植物暴露严重程度较低的被子植物的遗留物变异大。尽管生长变异性和遗留力之间的关系很复杂，但较大的生长变异性可以解释干旱地区裸子植物第一年RWI遗留物的存在。
4. 综合。对干旱的物种和场所响应进行核算，可以更好地了解干旱遗留对森林生长和生产力的影响程度和持续时间。尽管在干旱发生期间和干旱发生后的几年中普遍出现了生长减少的现象，但重大遗留不是很普遍，大多持续了一年，并且在裸子植物中更为普遍。这些是今后研究干旱对森林生产力和树木生长的影响时要考虑的相关因素。