1.       Mjell, T. L., Ninnemann, U. S., Kleiven, H. F.,& Hall, I. R. (2016). Multidecadal changes in Iceland Scotland OverflowWater vigor over the last 600 years and its relationship to climate. Geophys.Res. Lett, 43.

Changes in the Atlantic Meridional Overturning Circulation (AMOC) havecommonly been invoked to explain the low-frequency climate changes evident overmillennial-multidecadal timescales during the Holocene period. While there isgrowing evidence that deep ocean circulation varied on millennial timescales,little is known about ocean variability on shorter timescales. Here we use amarine sediment core (GS06-144-09MC-D) recovered from a high accumulation ratesite on the Gardar Drift in the Iceland Basin (60°19′N, 23°58′W, 2081 m) toreconstruct decadal-centennial variability in the vigor of Iceland-ScotlandOverflow Water (ISOW) with the paleocurrent proxy “sortable silt” mean grainsize SS. Our SS record reveals that changes in ISOW vigor have occurred onmultidecadal-centennial timescales over the past ~600 years; similar timescalesas documented in Atlantic Multidecadal Variability observations andreconstructions. Our findings support a link between changes in basin-wide climateand deep ocean circulation.

http://onlinelibrary.wiley.com/doi/10.1002/2016GL068227/pdf

2.       Suvanto, S., Nöjd, P., Henttonen, H. M., Beuker, E.,& Mäkinen, H. (2016). Geographical patterns in the radial growth responseof Norway spruce provenances to climatic variation. Agricultural and ForestMeteorology, 222, 10-20.

Changing climate is expected to cause range shifts and reduced growthin Norway spruce (Picea abies (L.) Karst). In order to mitigate these changes,genetic variation between populations can be utilized in selecting alternativetree origins that are better suited to the new conditions. The aim of thisstudy was to examine the intraspecific differences in the climatic drivers ofradial growth in Norway spruce. We used tree-ring data from seven Norway spruceprovenance experiments in Finland, located in different climatic conditions andincluding a large variety of provenances. The annual ring-width indices werestudied with hierarchical clustering, correlation analysis with climatevariables, pointer year analysis and linear models to identify the provenancedifferences in growth variation and its climatic control, and compare them on alatitudinal gradient. The cluster analysis revealed patterns of provenancedifferences in growth variation: north European and central Europeanprovenances were grouped in separate clusters within sites, although with someexceptions. Largest provenance differences in climate-growth responses werefound in relation to winter and spring temperatures. In the southernprovenances warm winters were typically associated with faster growth whereasfor the northern provenances the correlations varied from non-significant tonegative. In addition, the pointer year analysis showed negative growthanomalies only in the southern provenances for years with exceptionally coldwinters. These patterns may reflect the physiological differences between theprovenances relating to, for example, cold tolerance and the timing of springphenology. As the climate warming in Europe is predicted to be strongest duringthe winter months, acknowledging the intraspecific growth responses to climatein Norway spruce becomes increasingly important.

http://www.sciencedirect.com/science/article/pii/S016819231630185X

3.       Navarro-Cerrillo, R. M., Sánchez-Salguero, R.,Herrera, R., Ceacero Ruiz, C. J., Moreno-Rojas, J. M., Manzanedo, R. D., &López-Quintanilla, J. (2016). Contrasting growth and water use efficiency afterthinning in mixed Abies pinsapo–Pinus pinaster–Pinus sylvestris forests.Journal of Forest Science, 62(2), 53-64.

Foresters frequently lack sufficient information about thinning intensityeffects to optimize semi-natural forest management and their effects andinteraction with climate are still poorly understood. In an Abies pinsapo–Pinuspinaster–Pinus sylvestris forest with three thinning intensities, adendrochronologial approach was used to evaluate the short-term responses ofbasal area increment (BAI), carbon isotope (δ13C) and water use efficiency(iWUE) to thinning intensity and climate. Thinning generally increased BAI inall species, except for the heavy thinning in P. sylvestris. Across all theplots, thinning increased 13C-derived water-use efficiency on average by 14.49%for A. pinsapo, 9.78% for P. sylvestris and 6.68% for P. pinaster, but throughdifferent ecophysiological mechanisms. Our findings provide a robust mean ofpredicting water use efficiency responses from three coniferous species exposedto different thinning strategies which have been modulated by climaticconditions over time.

http://www.agriculturejournals.cz/publicFiles/175709.pdf

4.       Booth, R. K., Ireland, A. W., LeBoeuf, K., &Hessl, A. (2016). Late Holocene climate-induced forest transformation andpeatland establishment in the central Appalachians. Quaternary Research.

Understanding the potential for ecosystem transformation and communitychange in response to climate variability is central to anticipating futureecological changes, and long-term records provide a primary source ofinformation on these dynamics. We investigated the late Holocene history ofupland forest and peatland development at Cranesville Swamp, a peatland locatedalong the West Virginia–Maryland border in the USA. Our primary goal was todetermine whether establishment of peatland was triggered by moisture variability,similar to recent developmental models derived from depressional peatlands inglaciated regions. Results indicate that the peatland established at about 1200cal yr BP, and was associated with a dramatic and persistent change in uplandforest composition. Furthermore, timing of these upland and wetland ecologicalchanges corresponded with evidence for multidecadal drought and enhancedmoisture variability from nearby tree-ring and speleothem climaticreconstructions. Our results add to a growing body of research highlighting thesensitivity of both peatland development and upland forest communities totransient drought and enhanced moisture variability, and suggest that enhancedmoisture variability in the future could increase the probability of similarlyabrupt and persistent ecological change, even in humid regions like easternNorth America.

http://www.sciencedirect.com/science/article/pii/S0033589416000156

5.       Petrillo, M., Cherubini, P., Fravolini, G.,Marchetti, M., Ascher-Jenull, J., Schärer, M., ... & Egli, M. (2016). Timesince death and decay rate constants of Norway spruce and European larchdeadwood in subalpine forests determined using dendrochronology and radiocarbondating. Biogeosciences, 13(5), 1537-1552.

Due to the large size (e.g. sections of tree trunks) and highlyheterogeneous spatial distribution of deadwood, the timescales involved in thecoarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix deciduaMill. in Alpine forests are largely unknown. We investigated the CWD decaydynamics in an Alpine valley in Italy using the chronosequence approach and thefive-decay class system that is based on a macromorphological assessment. Forthe decay classes 1–3, most of the dendrochronological samples were cross-datedto assess the time that had elapsed since tree death, but for decay classes 4and 5 (poorly preserved tree rings) radiocarbon dating was used. In addition,density, cellulose, and lignin data were measured for the dated CWD. The decayrate constants for spruce and larch were estimated on the basis of the densityloss using a single negative exponential model, a regression approach, and thestagebased matrix model. In the decay classes 1–3, the ages of the CWD weresimilar and varied between 1 and 54 years for spruce and 3 and 40 years forlarch, with no significant differences between the classes; classes 1–3 aretherefore not indicative of deadwood age. This seems to be due to a time lagbetween the death of a standing tree and its contact with the soil. We founddistinct tree-species-specific differences in decay classes 4 and 5, with larchCWD reaching an average age of 210 years in class 5 and spruce only 77 years.The mean CWD rate constants were estimated to be in the range 0.018 to 0.022y−1 for spruce and to about 0.012 y−1 for larch. Snapshot sampling(chronosequences) may overestimate the age and mean residence time of CWD. Nosampling bias was, however, detectable using the stage-based matrix model.Cellulose and lignin time trends could be derived on the basis of the ages ofthe CWD. The half-lives for cellulose were 21 years for spruce and 50 years forlarch. The half-life of lignin is considerably higher and may be more than 100years in larch CWD. Consequently, the decay of Picea abies and Larix decidua isvery low. Several uncertainties, however, remain: 14C dating of CWD from decayclasses 4 and 5 and having a pre-bomb age is often difficult (large age rangedue to methodological constraints) and fall rates of both European larch andNorway spruce are missing.

http://www.biogeosciences.net/13/1537/2016/bg-13-1537-2016.pdf