Agricultural and Forest Meteorology ( IF 6.2 ) Pub Date : 2021-10-30 , DOI: 10.1016/j.agrformet.2021.108699 Camille Meeussen 1 , Sanne Govaert 1 , Thomas Vanneste 1 , Kurt Bollmann 2 , Jörg Brunet 3 , Kim Calders 4 , Sara A.O. Cousins 5, 6 , Karen De Pauw 1 , Martin Diekmann 7 , Cristina Gasperini 1, 8 , Per-Ola Hedwall 3 , Kristoffer Hylander 6, 9 , Giovanni Iacopetti 8 , Jonathan Lenoir 10 , Sigrid Lindmo 11 , Anna Orczewska 12 , Quentin Ponette 13 , Jan Plue 5 , Pieter Sanczuk 1 , Federico Selvi 8
Global forest cover is heavily fragmented. Due to high edge-to-surface ratios in small forest patches, a large proportion of forests is affected by edge influences involving steep microclimatic gradients. Although forest edges are important ecotones and account for 20% of the global forested area, it remains unclear how biotic and abiotic drivers affect forest edge microclimates at the continental scale. Here we report soil and air temperatures measured in 225 deciduous forest plots across Europe for two years. Forest stands were situated along a latitudinal gradient and subject to a varying vegetation structure as quantified by terrestrial laser scanning. In summer, the average offset of air and soil temperatures in forest edges compared to temperatures outside the forest amounted to -2.8 °C and -2.3 °C, respectively. Edge-to-interior summer temperature gradients were affected by the macroclimate and edge structure. From the edge onwards, larger offsets were observed in dense forest edges and in warmer, southern regions. In open forests and northern Europe, altered microclimatic conditions extended deeper into the forest and gradients were steeper. Canopy closure and plant area index were important drivers of summer offsets in edges, whereas in winter also the forest-floor biomass played a key role. Using high-resolution maps, we estimated that approximately 10% of the European broadleaved forests would be affected by altered temperature regimes. Gradual transition zones between forest and adjacent lands are valuable habitat types for edge species. However, if cool and moist forest interiors are desired, then (i) dense and complex forest edges, (ii) an undisturbed forested buffer zone of at least 12.5 m deep and (iii) trees with a high shade casting ability could all contribute to an increased offset. These findings provide important guidelines to mitigate edge influences, to protect typical forest microclimates and to adapt forest management to climate change.
中文翻译:
欧洲落叶林的小气候边缘到内部梯度
全球森林覆盖严重分散。由于小森林斑块中的边缘与表面比率很高,很大一部分森林受到边缘影响的影响,包括陡峭的小气候梯度。尽管森林边缘是重要的交错带,占全球森林面积的 20%,但目前尚不清楚生物和非生物驱动因素如何影响大陆尺度的森林边缘小气候。在这里,我们报告了两年来在欧洲 225 个落叶林地块中测量的土壤和空气温度。林分沿纬度梯度分布,并受到陆地激光扫描量化的不同植被结构的影响。在夏季,与森林外温度相比,森林边缘空气和土壤温度的平均偏移分别为 -2.8 °C 和 -2.3 °C。边缘到内部的夏季温度梯度受大气候和边缘结构的影响。从边缘开始,在茂密的森林边缘和温暖的南部地区观察到更大的偏移。在开阔的森林和北欧,改变后的小气候条件延伸到森林深处,坡度更陡峭。冠层关闭和植物面积指数是夏季边缘偏移的重要驱动因素,而在冬季,森林地面生物量也起着关键作用。使用高分辨率地图,我们估计大约 10% 的欧洲阔叶林将受到温度变化的影响。森林和相邻土地之间的逐渐过渡区是边缘物种的宝贵栖息地类型。然而,如果需要凉爽潮湿的森林内部,那么 (i) 密集而复杂的森林边缘,(ii) 至少 12.5 m 深的未受干扰的森林缓冲区和 (iii) 具有高遮荫能力的树木都可能有助于增加偏移量。这些发现为减轻边缘影响、保护典型的森林小气候和使森林管理适应气候变化提供了重要的指导方针。