The annual growth cycle of boreal trees is synchronized with seasonal changes in photoperiod and temperature. A warmer climate can lead to an earlier bud burst and increased risk of frost damage caused by temperature backlashes. In this study we analysed site- and provenance specific responses to interannual variation in temperature, using data from 18 Swedish and East-European provenances of Norway spruce (Picea abies), grown in three different sites in southern Sweden. The temperature sum requirements for bud burst, estimated from the provenance trials, were correlated with the provenance specific place of origin, in terms of latitudinal and longitudinal gradients. Frost damage had a significant effect on tree height development. Earlier timing of bud burst was linked to a higher risk of frost damage, with one of the sites being more prone to spring frost than the other two. The estimated provenance specific temperature sum requirements for bud burst were used to parametrize a temperature sum model of bud burst timing, which was then used together with the ensemble of gridded climate model data (RCP8.5) to assess the climate change impact on bud burst and associated risk of frost damage. In this respect, the simulated timing of bud burst and occurrence of frost events for the periods 2021–2050 and 2071–2100 were compared with 1989–2018. In response to a warmer climate, the total number of frost events in southern Sweden will decrease, while the number of frost events after bud burst will increase due to earlier bud burst timing. The provenance specific assessments of frost risk under climate change can be used for a selection of seed sources in Swedish forestry. In terms of selecting suitable provenances, knowledge on local climate conditions is of importance, as the gridded climate data may differ from local temperature conditions. A comparison with temperature logger data from ten different sites indicated that the gridded temperature data were a good proxy for the daily mean temperatures, but the gridded daily minimum temperatures tended to underestimate the local risk of frost events, in particular at the measurements 0.5 m above ground representing the height of newly established seedlings.

寒带树的年生长周期与光周期和温度的季节性变化同步。气候变暖会导致芽更早破裂，并因温度反弹而导致霜冻损坏的风险增加。在这项研究中，我们使用来自挪威云杉（Picea abies）的18种瑞典和东欧种源的数据，分析了站点和种源对温度年际变化的特定响应），生长在瑞典南部的三个不同地点。根据种源试验估算的芽爆发温度总和，在纬度和纵向梯度方面与种源特定产地相关。霜冻损害对树高发展有重大影响。芽破裂的较早时间与霜冻损坏的风险较高有关，其中一个部位比其他两个部位更容易发生春季霜冻。估计芽萌发的出处特定温度总和要求用于参数化芽萌发时间的温度总和模型，然后将其与网格化气候模型数据（RCP8.5）集合一起使用，以评估气候变化对芽萌发的影响以及相关的霜冻损坏风险。在这方面，将2021年至2050年和2071年至2100年期间芽破裂和霜冻事件发生的模拟时间与1989年至2018年进行了比较。为了应对气候变暖，瑞典南部霜冻事件的总数将减少，而芽破裂后的霜冻事件的数量将因芽破裂的时间提前而增加。气候变化下霜冻风险的出处特定评估可用于选择瑞典林业中的种子来源。就选择合适的出处而言，有关当地气候条件的知识非常重要，因为栅格化的气候数据可能与当地温度条件不同。与来自十个不同地点的温度记录器数据进行的比较表明，栅格化温度数据可以很好地代表每日平均温度，