1.     Stahle, D. W.,Cook, E. R., Burnette, D. J., Villanueva, J., Cerano, J., Burns, J. N., ...& Sjezner, P. (2016). The Mexican Drought Atlas: Tree-ring reconstructionsof the soil moisture balance during the late pre-Hispanic, colonial, and moderneras. QuaternaryScience Reviews, 149, 34-60.

Mexicohas suffered a long history and prehistory of severe sustained drought. Droughtover Mexico is modulated by ocean-atmospheric variability in the Atlantic andPacific, raising the possibility for long-range seasonal climate forecasting,which could help mediate the economic and social impacts of future dry spells.The instrumental record of Mexican climate is very limited before 1920, buttree-ring chronologies developed from old-growth forests in Mexico can providean excellent proxy representation of the spatial pattern and intensity of pastmoisture regimes useful for the analysis of climate dynamics and climateimpacts. The Mexican Drought Atlas (MXDA) has been developed from an extensivenetwork of 252 climate sensitive tree-ring chronologies in and near Mexico. TheMXDA reconstructions extend from 1400 CE–2012 and were calibrated with theinstrumental summer (JJA) self-calibrating Palmer Drought Severity Index(scPDSI) on a 0.5° latitude/longitude grid extending over land areas from 14 to34°N and 75–120°W using Ensemble Point-by-Point Regression (EPPR) for the1944–1984 period. The grid point reconstructions were validated for the period1920–1943 against instrumental gridded scPDSI values based on the fewer weatherstation observations available during that interval. The MXDA provides a newspatial perspective on the historical impacts of moisture extremes over Mexicoduring the past 600-years, including the Aztec Drought of One Rabbit in 1454,the drought of El Año de Hambre in 1785–1786, and the drought that preceded theMexican Revolution of 1909–1910.

The ElNiño/Southern Oscillation (ENSO) is the most important ocean-atmosphericforcing of moisture variability detected with the MXDA. In fact, thereconstructions suggest that the strongest central equatorial Pacific sea surfacetemperature (SST) teleconnection to the soil moisture balance over NorthAmerica may reside in northern Mexico. This ENSO signal has stronger and moretime-stable correlations than computed for either the Atlantic MultidecadalOscillation or Pacific Decadal Oscillation. The extended Multivariate ENSOIndex is most highly correlated with reconstructed scPDSI over northern Mexico,where warm events favor moist conditions during the winter, spring, and earlysummer. This ENSO teleconnection to northern Mexico has been strong over thepast 150 years, but it has been comparatively weak and non-stationary in theMXDA over central and southern Mexico where eastern tropical Pacific andCaribbean/tropical Atlantic SSTs seem to be more important. The ENSO teleconnectionto northern Mexico is weaker in the available instrumental PDSI, but analysesbased on the millennium climate simulations with the Community Earth SystemModel suggest that the moisture balance during the winter, spring, and earlysummer over northern Mexico may indeed be particularly sensitive to ENSOforcing. Nationwide drought is predicted to become more common withanthropogenic climate change, but the MXDA reconstructions indicate thatintense “All Mexico” droughts have been rare over the past 600 years and theirfrequency does not appear to have increased substantially in recent decades.

http://www.sciencedirect.com/science/article/pii/S0277379116302244

2.     Šilhán, K.,Prokešová, R., Medveďová, A., & Tichavsky, R. (2016). The effectiveness ofdendrogeomorphic methods for reconstruction of past spatio-temporal landslidebehaviour. CATENA, 147, 325-333.

Dendrogeomorphic methods are in fact frequentlyused for spatio-temporal landslide behaviour reconstruction. However, theirreal accuracies have not yet been deeply evaluated. The purpose of this studyis to evaluate the effectiveness and accuracy of tree ring based methods bycomparing them with field monitoring data on landslide behaviours. A total of876 increment cores have been extracted from 219 P. sylvestris individuals toreconstruct the past spatio-temporal activity of the Ľubietová landslide(1977). The landslide re-activation events recorded within the tree ring seriesof each tree have been spatially interpolated. Those data have been comparedwith the long-term field monitoring based on the measured changes in the stabilizedgeodetic point positions.

In general, the tree ring based spatio-temporallandslide evolution revealed a higher landslide activity than themonitoring-based one (particularly in the lower part of the landslide).However, higher activity was recorded from the monitoring in the northern partof the upper half of the landslide, while approximately 30% of the studiedlandslide area revealed highly similar normalized values based on bothapproaches. The best fit between the results (> 80%) was in areas with meancumulative surface displacements of approximately 200 mm (monitoring basedresults) and mean event recurrence time of 14.5 years (tree ring basedresults). The potential sources of uncertainties that should be considered infuture dendrogeomorphic research are the irregular spatial positions andspatial density of trees, the physiology of the tree species, the inertia oftree growth responses within tree ring sequences and the type of studiedlandslide.

http://www.sciencedirect.com/science/article/pii/S0341816216302946

3.     Natalini, F.,Alejano, R., Vázquez-Piqué, J., Pardos, M., Calama, R., & Büntgen, U.(2016). Spatiotemporal variability of stone pine (Pinus pinea L.) growthresponse to climate across the Iberian Peninsula. Dendrochronologia,40, 72-84.

Climate warming and increasing aridity haveimpacted diverse ecosystems in the Mediterranean region since at least the1970s. Pinus pinea L. has significant environmental and socio-economicimportance for the Iberian Peninsula, so a detailed understanding of its responseto climate change is necessary to predict its status under future climaticconditions. However, variability of climate and uncertainties indendroclimatological approach complicate the understanding of forest growthdynamics. We use an ensemble approach to analyze growth-climate responses of P.pinea trees from five sites along a latitudinal gradient in Spain over time.The growth responses to April-June precipitation totals were stronger in thenorth than in the south. Since the 1950s, the sensitivity of growth toApril-June precipitation increased in the north and decreased in the south.Meteorological drought usually started in May in the southern sites, but inJune-July in the northern sites. The water deficit in the southern sites isthus greater and more limiting for tree growth, and this likely accounts forthe lower growth sensitivity during these months. Our results indicate that P.pinea has a high degree of plasticity, suggesting the species will withstandchanging climatic conditions. However, growth response to drought regimesvaries among P. pinea populations, suggesting that different populations havedifferent capacities for acclimation to warmer and drier climate, and this mayinfluence future vegetation composition.

http://www.sciencedirect.com/science/article/pii/S1125786516300777

4.     Krąpiec, M.,Margielewski, W., Korzeń, K., Szychowska-Krąpiec, E., Nalepka, D., &Łajczak, A. (2016). Late Holocene palaeoclimate variability: The significanceof bog pine dendrochronology related to peat stratigraphy. The Puścizna Wielkaraised bog case study (Orawa–Nowy Targ Basin, Polish Inner Carpathians). QuaternaryScience Reviews, 148, 192-208.

The results of dendrochronological andpalynological analyses of subfossil pine trees occurring in the peat depositsof the Puścizna Wielka raised bog (Polish Carpathians, Southern Poland) – theonly site with numerous subfossil pine trees in the mountainous regions ofCentral Europe presently known – indicate that the majority of the treepopulations grew in the peat bog during the periods ca 5415–3940 cal BP and3050–2560 cal BP. Several forestless episodes, dated to 5245–5155 cal BP,4525–4395 cal BP and 3940–3050 cal BP, were preceded by tree dying-off phasescaused by an extreme periodical increase in humidity and general climatecooling trends. These events are documented based on analyses of pollen andnon-pollen palynomorph assemblages, dendrochronological analyses of the trees,as well as numerous radiocarbon datings of the sediment horizons occurringwithin the peat bog profile. The phases of germinations, and, in turn, of treeand shrub invasions of the peat bog areas have been closely connected to dryingand occasional warming of the regional climate. The last of the forestlessperiods began about 2600 years ago and continued up to the very recent times.Currently, as a result of desiccation of the peat bog and the lowering of thegroundwater level (due to improved water drainage system), pine trees havereturned the peat bog again. These results demonstrate that studies ofsubfossil bog-pine trees are quite effective in documenting and reconstructingperiods of humidity fluctuation that occurred within the Carpathian region overthe last several millennia.

http://www.sciencedirect.com/science/article/pii/S0277379116302578

5.     Grote, R.,Gessler, A., Hommel, R., Poschenrieder, W., & Priesack, E. (2016).Importance of tree height and social position for drought-related stress ontree growth and mortality. Trees, 1-16.

Drought stress can trigger tree mortality butthe impact depends on stress intensity (water demand and availability) and onthe vulnerability of the individual. Therefore, most research focusses on thespecies-specific properties such as water use efficiency or hydraulicconductivity that determine vulnerability. At the ecosystem scale, however,tree properties that have been found important for drought sensitivity orresistance vary with individual size and resource availability within aforest—also within the same species. This is caused by different environmentalconditions for each tree and hence different growth histories of individualsgenerating specific anatomical and physiological features. Individual droughtstress sensitivity might thus be considerably different from stand scalesensitivity. Indeed, empirical evidence shows that drought stress impactdepends on tree social position which can be defined in degrees of suppressionbut correlated to resource availability, stress sensitivity and stressexposure. In this review, we collect such evidence and discuss the role ofmicroclimate and soil water distribution as well as anatomical andphysiological adjustments, which might serve as foundation for better-adaptedmanagement strategies to mitigate drought stress impacts. Finally, we definemodel requirements aiming to capture stand-scale drought responses ormanagement impacts related to drought stress mitigation.

http://link.springer.com/article/10.1007/s00468-016-1446-x

6.     BOJAXHI, F.,& TOROMANI, E. (2016). The Growth of Bosnian Pine (Pinus heldreichiiChrist.) at Tree Line Locations from Kosovo and its Response to Climate. South-eastEur for, 7(2), 16-10.

Background and Purpose: Pinus heldreichiiChrist. is a sub-endemic species occurring at tree-line locations in Kosovo andcoveringan area of 2500 ha. In high elevation sites radial growth is mainly controlledby low temperatures. The main purpose of this study was the analysis of radialgrowth of P. heldreichii and its response to local climate conditions.

Materials and Methods: Research sites compriseof three high elevation stands of P. heldreichii with specific site conditions.Core samples were collected from 98 healthy dominant and co-dominant trees atbreast height using increment borer. They were prepared and cross-dated usingstandard dendrochronological methods, while tree-ring widths were measured to thenearest 0.001 mm using the TSAP software. The ARSTAN program was used tostandardize the tree-ring widths and to calculate dendrochronologicalstatistical parameters. The growth-climate relationship was investigated usingbootstrapped correlation function analysing the residual chronologies of eachsampled site as a dependent variable and the climatic data from May of the(n-1) year up to the October of the n year for the common period 1951-2013 asan independent variable.

Results: The length of Bosnian pinechronologies ranged from 175 to 541 years. All chronologies had high values offirstorder autocorrelation indicating that radial growth of P. heldreichii isaffected by the climate conditions of the previousgrowing year. Koritnikchronology had the highest values of the mean sensitivity due to the influenceof drought stress. This conclusion is also supported by the result ofgrowth-climate relationship where radial growth is negatively correlated withJune temperatures and positively associated with July and August precipitation.We found that radial growth of young trees from Koritnik site is limited by thecombined effect of temperatures and summer drought stress. In high elevation sites,temperature is expected to control the growth of P. heldreichii, but thiseffect is becoming more restrictive with age. The positive correlation betweenradial growth and winter temperatures suggests that favorable thermalconditions during winter months influence snow melting or soil moistureavailability and indirectly affect the radial growth of P. heldreichii at allthree sampled sites.

Conclusions: The first tree-ring widthchronologies from Kosovo are an important step towards a denser tree ringnetwork in the Balkan region. Growth-climate relationships indicated that forP.heldreichii growth does not depend only on one single dominant factor, butalso on various combinations of precipitation and temperature resulting indifferent climatic sensitivity. Our results provide an important basis foradditional tree-ring parameters such as maximum latewood density and stableisotope ratios to be processed, improving the level of knowledge about P.heldreichii’s response versus site conditions.

http://www.seefor.eu/images/arhiva/vol7_no2/bojaxhi_toromani/bojaxhi_toromani.pdf