Sitka spruce is the major conifer species in British upland forests and is predominantly managed as even-aged, single-species plantations with rotation lengths of less than 50 years using a “patch clear-felling” system. Evidence on the impact of clear-felling on the carbon, water, and energy balances of plantation forestry is sparse and extreme weather events, such as the 2018 drought that occurred across Europe, are expected to have considerable impact. We used energy balance and gas flux data from a typical mature stand and a clear-felled site on peaty-gley soil at Harwood Forest in Northumberland, UK, over 4 years to quantify the impact of clear-felling and investigate how the drought of 2018 affected these fluxes. Felling resulted in an annual CO₂ source (7.05 $\text{tC}{\text{ha}}^{-1}{\text{yr}}^{-1}$) of similar magnitude in absolute terms to the mature stand sink (7.09 $\text{tC}{\text{ha}}^{-1}{\text{yr}}^{-1}$). The source was reduced with the growth of ground vegetation, and after tree replanting two years post-felling, the site was a weak source. Felling increased reflected radiation by 92%, reduced evapotranspiration by 28% and therefore increased site wetness by 8%, while replanting and the spread of ground vegetation increased evapotranspiration by 16% on average. The warm, dry spring and summer in 2018 increased evapotranspiration and reduced net carbon uptake of the mature stand by 30% compared to the mean of the previous three years, because of a small decrease in photosynthetic uptake and a small increase in ecosystem respiration. The drought conditions also increased ecosystem losses of CO₂ at the clear-felled site by 28%. The clear-fell site would have turned into a small CO₂ sink in the second year after replanting, if there had not been a drought.

锡特卡云杉是英国山地森林中的主要针叶树种，主要使用“补丁清除”系统，作为轮龄不到50年的单龄，单种人工林进行管理。清除砍伐对人工林的碳，水和能源平衡的影响的证据很少，极端天气事件（例如，欧洲在2018年发生的干旱）预计会产生重大影响。我们使用了来自英国诺森伯兰郡哈伍德森林（Harwood Forest）的典型成熟林地和一片灰质土壤上清晰的采伐场的能量平衡和气体通量数据，历时4年，以量化采伐的影响并调查2018年的干旱如何影响了这些通量。砍伐导致年度CO ₂排放源（7.05 $\text{温度}{\text{哈}}^{-\mathrm{1个}}{\text{年}}^{-\mathrm{1个}}$），其绝对值与成熟的立场下沉（7.09 $\text{温度}{\text{哈}}^{-\mathrm{1个}}{\text{年}}^{-\mathrm{1个}}$）。随着地面植被的生长，该源减少了，砍伐后两年重新植树后，该地点是一个弱源。砍伐使反射辐射增加了92％，使蒸散量减少了28％，因此使场地湿度增加了8％，而重新种植和地面植被的扩散平均使蒸散量增加了16％。与前三年的平均值相比，2018年春季和夏季温暖，干燥，增加了蒸散量，使成熟林分的净碳吸收量降低了30％，这是因为光合吸收量略有下降，生态系统呼吸量也略有增加。干旱条件也使荒地上的CO ₂生态系统损失增加了28％。掉落场地将变成少量的CO ₂ 如果没有干旱，则在第二年下沉。