Greiser et al. (2023) Higher soil moisture increases microclimate temperature buffering in temperate broadleaf forests - Data and Code

Abstract of the article to which the data and code belong:Forest canopies can buffer the understory against temperature extremes often creating cooler microclimates during warm summer days compared to temperatures outside the forest. The buffering of maximum temperatures in the understory results from a combination of canopy shading and air cooling through soil water evaporation and plant transpiration. Therefore, buffering capacity of forests depends on canopy cover and soil moisture content, which are increasingly affected by more frequent and severe canopy disturbances and soil droughts. The extent to which this buffering will be maintained in future conditions is unclear due to the lack of understanding about the relationship between soil moisture and air temperature buffering in interaction with canopy cover and topographic settings. We explored how soil moisture variability affects temperature offsets between outside and inside the forest on a daily basis, using temperature and soil moisture data from 54 sites in temperate broadleaf forests in Central Europe over four climatically different summer seasons. Daily maximum temperatures in forest understories were on average 2 °C cooler than outside temperatures. The buffering of understory temperatures was more effective when soil moisture was higher, and the offsets were more sensitive to soil moisture on sites with drier soils and on sun-exposed slopes with high topographic heat load. Based on these results, the soil-water limitation to forest temperature buffering will become more prevalent under future warmer conditions and will likely lead to changes in understory communities. Thus, our results highlight the urgent need to include soil moisture in models and predictions of forest microclimate, understory biodiversity and tree regeneration, to provide a more precise estimate of the effects of climate change.List of files:02_model_offset_from_soilmoist_rev.r =&gt; R-script for the statistical analysismodel_data_complete_figshare.csv =&gt; cleaned and complete data for the statistical analysismodel_data_4thday_figshare.csv =&gt; cleaned and "thinned" data for the statistical analysisREADME.txt =&gt; metadata describing columns in the dataframes and the environment of the R-script<br><br><br><br><br><br>

本数据集与代码所属论文的摘要如下：林冠（forest canopy）可缓冲林下生境的极端温度，在炎热夏季常能营造出较林外更低的微气候环境。林下最高温的缓冲效应源于林冠遮阴与土壤水分蒸发、植物蒸腾共同带来的空气降温作用。因此，森林的温度缓冲能力取决于林冠覆盖度与土壤含水量，而这两项因素正日益受到更频繁、更严重的林冠干扰与土壤干旱的影响。目前学界对土壤水分、气温缓冲效应与林冠覆盖度、地形条件的交互作用机制尚缺乏认知，因此未来气候情景下森林能否维持这一缓冲能力仍不明朗。本研究基于中欧温带阔叶林54个样点在四个气候特征各异的夏季采集的气温与土壤水分数据，逐日分析了土壤水分变异对林内外温差的影响。林下每日最高温平均较林外低2℃。当土壤含水量更高时，林下温度的缓冲效应更为显著；而在土壤偏干旱的样点与地形热负荷较高的向阳坡地，林内外温差对土壤水分的变化更为敏感。基于上述研究结果，未来气候变暖背景下，土壤水分对森林温度缓冲效应的限制作用将愈发普遍，并可能引发林下群落结构的改变。因此，本研究结果凸显了亟需将土壤水分因子纳入森林微气候、林下生物多样性与树木更新的模型与预测当中，以更精准地评估气候变化带来的影响。

文件列表：
02_model_offset_from_soilmoist_rev.r：用于统计分析的R脚本
model_data_complete_figshare.csv：用于统计分析的完整预处理数据集
model_data_4thday_figshare.csv：用于统计分析的经清理与“抽稀”处理的数据集
README.txt：描述数据框列信息与R脚本运行环境的元数据文件