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Ice-wedge polygon mires feature a micro-relief of dry ridges, shallow wet depressions, deeper wet troughs and transitional sites, resulting in a local mosaic of vegetation. The correct recognition of these landscape elements in palaeoecological studies of peat sections requires insight about the suitability of proxies and their potential for palaeoecological reconstruction in order to reconstruct vegetation and wetness patterns as well as dynamics. This paper analyses a 105.5 cm long peat section with a base dating to about 4000 cal yr BP from an ice-wedge polygon mire near Kytalyk (NE Siberia). Pollen, macrofossils, testate amoebae, geochemistry and sediment properties were analysed in order to compare the suitability of these proxies to reconstruct past surface wetness. The proxies show similar wetness trends. Pollen and geochemistry data did not always permit wetness reconstruction, the former because many pollen types do not allow the identification of taxa at a low taxonomic resolution, the latter because later taphonomic processes modify chemical variables in deeper peat layers. Macrofossils provided the most detailed wetness reconstruction, because they could be identified to genera or species, for which the moisture requirements are accurately known from their present-day distribution in ice-wedge polygons. All proxies, except geochemistry, show an obvious change from wet to dry conditions at around 20 cm depth. However, as the proxies sometimes show contradictory results, a multi-proxy approach is preferable over a single proxy interpretation as it allows the reconstruction of environmental development in a broader palaeoecological context. Figure 2 Location of ice-wedge polygon Lhc11 near the Kytalyk research station along the Berelekh River: (A, B) the study area, indicated are the most important landforms; (C) satellite image of the study area (GeoEye image from 2010, 0.5 m resolution, by courtesy of K. van Huissteden, Vrije Universiteit, Faculty of Earth and Life Sciences, Amsterdam); and (D) ice-wedge polygon Lhc11. This figure is available in colour online at wileyonlinelibrary.com/journal/ppp 78 A. Teltewskoi et al.

Spring phenology of temperate forest trees has advanced substantially over the last decades due to climate warming, but this advancement is slowing down despite continuous temperature rise. The decline in spring advancement is often attributed to winter warming, which could reduce chilling and thus delay dormancy release. However, mechanistic evidence of a phenological response to warmer winter temperatures is missing. We aimed to understand the contrasting effects of warming on plants leaf phenology and to disentangle temperature effects during different seasons. With a series of monthly experimental warming by ca. 2.4°C from late summer until spring, we quantified phenological responses of forest tree to warming for each month separately, using seedlings of four common European tree species. To reveal the underlying mechanism, we tracked the development of dormancy depth under ambient conditions as well as directly after each experimental warming. In addition, we quantified the temperature response of leaf senescence. As expected, warmer spring temperatures led to earlier leaf‐out. The advancing effect of warming started already in January and increased towards the time of flushing, reaching 2.5 days/°C. Most interestingly, however, warming in October had the opposite effect and delayed spring phenology by 2.4 days/°C on average; despite six months between the warming and the flushing. The switch between the delaying and advancing effect occurred already in December. We conclude that not warmer winters but rather the shortening of winter, i.e., warming in autumn, is a major reason for the decline in spring phenology.

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