Croatian hilly coastal area from north-eastern part of Adriatic Sea is characterized by limestone, Mediterranean climate, bora wind and black pine trees (Pinus nigra Arnold). Trees, growing in such environment, suffer summer drought stress as a result of shallow soil, low summer precipitation and high air and ground temperatures. But which climatic factor significantly (precipitation, air temperature or sunshine hours) mostly influences tree growth and tree-ring density? To answer these questions, cores of trees were taken to perform tree-ring width (TRW) measurements using ATRICS and tree-ring density (MXD) measurements using minimum blue reflectance. Climate signal was calculated using simple correlation analysis between tree-ring proxy and climate data from HISTALP database of the nearest weather station. Main results represent newly developed site chronology, extending period from 1869 till 2012. Chronology matches well with other local black pine chronologies. TRW was positively affected by June-July precipitation (r=0.34) and negatively by summer season temperatures (r=-0.32). Sunshine hours had no influence on TRW, but had positive on MXD in April-June period (r=0.51). Stronger was influence of temperatures of April-August period on MXD (r=0.68), while precipitation influenced negatively in months June and July (r=-0.33). Tree-ring proxies reacted differently to climate factors through time. The period with the least climatic influence is around 1930s and 1980s. Concluding, TRW reacted similarly strong to summer precipitation, air temperature and sunshine hours, suggesting a complex climate signal, therefore drought index investigation should also be tested. Highest correlations were calculated between MXD and temperatures from April-August period. High temperatures in this period increased MXD, but decreased TRW. Forest management strategies for this region need to take this facts into account. Detailed look with running correlation revealed instability of the tree-growth reaction to climate factors. Further climate– tree data relationship investigations are necessary to discover, why trees change reaction to climate factor.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 4119718Bosnian pine (Pinus heldreichii Christ) - PIHE, is a species native to mountainous areas of the Balkans and southern Italy. PIHE is a tree species of the upper tree line in the Dinaric mountains and as such a promising source of valuable climate information. Due to its longevity it might have a good potential for long climate reconstructions based solely on living trees. Aim of our study was to investigate potential of PIHE (1) for construction of long PIHE chronologies for the region of the central W Balkan and (2) for long climate reconstructions based mostly on cores from living trees. Preliminary PIHE chronology is 437 (1573-present) years long and has a sufficient sample depth for EPS)0.85 from 1659 onwards. Comparison with climate data show specific response of PIHE to climate – trees respond positively to above average temperature in March (Mt) and negatively to above average temperature in June and July (JJt). We found weak positive response to June and July precipitation (JJp). This is somehow expected since precipitation are abundant along the Dinaric mountain ridge and are not factor in minima. Running window statistics reveal a significant temporal change in the identified signals – JJt and JJp signals were significant before 1965, and Mt after 1965.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 4167846Carbon, oxygen and hydrogen isotope chronologies of tree-rings of larch growing in southeastern Alps are strongly correlated, with correlation between water isotopes being the strongest. Chronologies of tree-ring width contain information of climate conditions in the period between May and July, while isotope chronologies are strongly correlated with temperatures and sunshine duration in July and August. Spatial correlation pattern between carbon isotope chronology, tree-ring width chronology and measured temperatures spreads over wider area of Alps, while in case of water isotopes it covers the area of southern Italy and western Balkan. A 520 years long reconstruction of sunshine duration was constructed based on carbon isotope chronology. Its comparison with existent temperature reconstructions reveals period when temperature and sunshine duration covariate and when they diverge. In the Krakovo forest, pedunculated oaks from peridicaly flooded micro-location (W oaks) grew significantly better than oaks from the drier micro-location (D dobi) through the whole analysed period (1979-2008). In D oak, potential climate information is stored in earlywood and is correlated with climate conditions in the previous year. There was no clear response to environmental factors in the latewood and it appears to be blurred by the response of trees to long term stressed conditions. High positive correlation between summer precipitation amount, summer Krka River flow and latewood parameters of W oaks indicates their potential for use in dendrohydrological studies.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 842359