Abstract We quantified the response of peatland water table level (WTL) and energy fluxes to harvesting of a drained peatland forest. Two alternative harvests (clear-cut and partial harvest) were carried out in a mixed-species ditch-drained peatland forest in southern Finland, where water and energy balance components were monitored for six pre-treatment and three post-treatment growing seasons. To explore the responses caused by harvestings, we applied a mechanistic multi-layer soil-plant-atmosphere transfer model. At the clear-cut site, the mean growing season WTL rose by 0.18 ± 0.02 m (error estimate based on measurement uncertainty), while net radiation, and sensible and latent heat fluxes decreased after harvest. On the contrary, we observed only minor changes in energy fluxes and mean WTL (0.05 ± 0.03 m increase) at the partial harvest site, although as much as 70% of the stand basal area was removed and leaf-area index was reduced to half. The small changes were mainly explained by increased water use of spruce undergrowth and field layer vegetation, as well as increased forest floor evaporation. The rapid establishment of field layer vegetation had a significant role in energy balance recovery at the clear-cut site. At partial harvest, chlorophyll fluorescence measurements and model-data comparison suggested the shade-adapted spruce undergrowth was suffering from light stress during the first post-harvest growing season. We conclude that in addition to stand basal area, species composition and stand structure need to be considered when controlling WTL in peatland forests with partial harvesting. Our results have important implications on the operational use of continuous cover forestry on drained peatlands. A continuously maintained tree cover with significant evapotranspiration capacity could enable optimizing WTL from both tree growth and environmental perspectives.

中文翻译：

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排水泥炭地森林水和能量平衡的植被控制：对替代采伐做法的反应

摘要 我们量化了泥炭地地下水位水平 (WTL) 和能量通量对采伐排水泥炭地森林的响应。在芬兰南部的一个混合物种沟渠排水泥炭地森林中进行了两种替代采伐（明确采伐和部分采伐），在那里监测了六个预处理和三个处理后生长季节的水和能量平衡成分。为了探索收获引起的反应，我们应用了一个机械多层土壤-植物-大气转移模型。在净地，平均生长季 WTL 增加了 0.18 ± 0.02 m（基于测量不确定性的误差估计），而净辐射、感热和潜热通量在收获后下降。相反，我们在部分收获地点仅观察到能量通量和平均 WTL（增加 0.05 ± 0.03 m）的微小变化，尽管多达 70% 的林分基础面积被移除，叶面积指数减少到一半。小的变化主要是由于云杉林下和田间植被的用水量增加以及森林地面蒸发量增加所致。田间层植被的快速建立对空地能量平衡恢复具有重要作用。在部分收获时，叶绿素荧光测量和模型数据比较表明，在收获后的第一个生长季节，适应阴凉的云杉灌木丛遭受光胁迫。我们得出的结论是，在部分采伐泥炭地森林中控制 WTL 时，除了林分基面积外，还需要考虑物种组成和林分结构。我们的结果对排水泥炭地连续覆盖林业的运营使用具有重要意义。具有显着蒸发蒸腾能力的持续保持的树木覆盖可以从树木生长和环境的角度优化 WTL。