Description: Trees, as long living plants, are governed by environmental and/or climate changes within their habitat. Their growth rings record to a large extent the temporal dynamics of these changes either directly or through tree physiological reactions. They render the highest time resolution thus far possible for environmental or climate reconstructions of the past 10,000 years (exactly dated, annually resolved, see: [828], [994]). Trees are a substantial part of the human environment with a high socio-economic value. Their large geographical extension over various regions of the world, including those with greatest population densities but also marginal areas allows to gain unique informations about local and regional consequences of global climate change.

Description: Stable carbon and oxygen isotope ratios of raw pollen sampled from nine abundant tree species growing in natural habitats of central and northern Europe were investigated to understand the intra- and inter-specific variability of pollen-isotope values. All species yielded specific δ13Cpollen and δ18Opollen values and patterns, which can be ascribed to their physiology and habitat preferences. Broad-leaved trees flowering early in the year before leaf proliferation (Alnus glutinosa and Corylus avellana) exhibited on average 2.6‰ lower δ13Cpollen and 3.1‰ lower δ18Opollen values than broad-leaved and coniferous trees flowering during mid and late spring (Acer pseudoplatanus, Betula pendula, Carpinus betulus, Fagus sylvatica, Picea abies, Pinus sylvestris and Quercus robur). Mean species-specific δ13Cpollen values did not change markedly over time, whereas δ18Opollen values of two consecutive years were often statistically distinct. An intra-annual analysis of B. pendula and P. sylvestris pollen revealed increasing δ18Opollen values during the final weeks of pollen development. However, the δ13Cpollen values remained consistent throughout the pollen-maturation process. Detailed intra-individual analysis yielded circumferential and height-dependent variations within carbon and oxygen pollen-isotopes and the sampling position on a tree accounted for differences of up to 3.5‰ for δ13Cpollen and 2.1‰ for δ18Opollen. A comparison of isotope ranges from different geographic settings revealed gradients between maritime and continental as well as between high and low altitudinal study sites. The results of stepwise regression analysis demonstrated, that carbon and oxygen pollen-isotopes also reflect local non-climate environmental conditions. A detailed understanding of isotope patterns and ranges in modern pollen is necessary to enhance the accuracy of palaeoclimate investigations on δ13C and δ18O of fossil pollen. Furthermore, pollen-isotope values are species-specific and the analysis of species growing during different phenophases may be valuable for palaeoweather reconstructions of different seasons.

Description: This publication is a result of the 15th TRACE conference „Tree Rings in Archaeology, Climatologyand Ecology” organized by the University of Silesia, Silesian Botanical Garden, University ofWrocław, Forest Research Institute and Białowieża National Park. The conference was held onMay 11th – 15th, 2016 in Białowieża, Poland, in the heart of the Białowieża Forest, the last naturalforest in the European Lowlands, a UNESCO World Heritage Site and Biosphere Reserve. University Pablo de Olavide (UPO) and the Association for Tree-ring Research (ATR), in collaboration with Pyrenean Institute of Ecology-Spanish National Research Council (IPE-CSIC), University of Barcelona (UB), Forest and Wood Technology Research Centre (CETEMAS) and University of Valladolid (UVa). The TRACE 2015 conference was held on May 20-23, 2015 for the first time in the Iberian Peninsula, in Sevilla, Spain.

Description: This publication is a result of the 14th TRACE conference (Tree Rings in Archaeology, Climatology and Ecology) organized by the Department Physical, Chemical and Natural Systems of the University Pablo de Olavide (UPO) and the Association for Tree-ring Research (ATR), in collaboration with Pyrenean Institute of Ecology-Spanish National Research Council (IPE-CSIC), University of Barcelona (UB), Forest and Wood Technology Research Centre (CETEMAS) and University of Valladolid (UVa). The TRACE 2015 conference was held on May 20-23, 2015 for the first time in the Iberian Peninsula, in Sevilla, Spain.

Description: The Northeast German Lowland Observatory (TERENO‐NE) was established to investigate the regional impact of climate and land use change. TERENO‐NE focuses on the Northeast German lowlands, for which a high vulnerability has been determined due to increasing temperatures and decreasing amounts of precipitation projected for the coming decades. To facilitate in‐depth evaluations of the effects of climate and land use changes and to separate the effects of natural and anthropogenic drivers in the region, six sites were chosen for comprehensive monitoring. In addition, at selected sites, geoarchives were used to substantially extend the instrumental records back in time. It is this combination of diverse disciplines working across different time scales that makes the observatory TERENO‐NE a unique observation platform. We provide information about the general characteristics of the observatory and its six monitoring sites and present examples of interdisciplinary research activities at some of these sites. We also illustrate how monitoring improves process understanding, how remote sensing techniques are fine‐tuned by the most comprehensive ground‐truthing site DEMMIN, how soil erosion dynamics have evolved, how greenhouse gas monitoring of rewetted peatlands can reveal unexpected mechanisms, and how proxy data provides a long‐term perspective of current ongoing changes.

Description: An annually resolved chronologies of oxygen isotopes from five living oak (Quercus robur) trees have been measured from tree ring cellulose covering up to the last 180 years (1836CE – 2020CE). This tree-ring stable isotope data set was established within the ‘Terrestrial Environmental Observatories’ (TERENO) of the Helmholtz Association. The site “Lake Tiefer See” is subject to the TERENO monitoring activities at the Northeast German Lowland Observatory coordinated by the GFZ German Research Centre for Geosciences in Potsdam. The data set comprises the δ18O records with respect to the international VSMOW standard. Lake Tiefer See (53°350 N, 12°320 E) is located 90 km NNW of Berlin in the morainic terrain of the NE-German Polish Basin. It is part of in the N–S trending Klocksin Lake Chain. The sampled trees are growing at the southern shore of the lake. Fifteen co-dominant Quercus robur tree individuals were cored at about 1.3m above ground from two opposite positions using an increment corer of 5 mm diameter (Suunto, Finland or Mora, Sweden).