Multiple tree-ring proxies (earlywood width, latewood width and δ13C) from pedunculate oak (Quercus robur L.), Hungary

Abstract

The aim of this study was to analyse the effects of climatic factors (i.e. monthly mean temperature and total precipitation) on radial growth (earlywood width, latewood width, and total ringwidth) and on latewood stable carbon isotope composition in a pedunculate oak (Quercus robur L.) stand in northeastern Hungary. Earlywood widths showed the weakest common variance and lack of statistically significant relationship to monthly precipitation and temperature. Latewood width showed the strongest common chronological signal. Correlation analysis with the monthly climate series pointed out the strongest positive/negative correlation with June precipitation for latewood width/stable carbon isotope ratio. These parameters shared the strongest climatic response also for seasonal scale since the highest correlation coefficients, 0.49 and -0.62 for latewood width and stable carbon isotope ratio, respectively, were obtained for both with a 10-month precipitation total (from previous November to current August of the growing season). A combined parameter, derived as difference between latewood width and stable carbon isotope indices showed improved statistical relationship compared to the hydroclimatic calibration target both for local and regional spatial scales. Spatial correlation analysis indicated that the hydroclimatic signal encoded in these moisture sensitive tree-ring parameters from Bakta Forest is expected to be representative for the northeastern Carpathians and for the large part of the Great Hungarian Plain. In addition, the hydroclimatic signal of latewood width chronology was compared to three independent records. Results showed that neither the strength nor the rank of the similarity of the local hydroclimate signals were stable throughout the past two centuries. Future palaeo(hydro)climatological efforts targeting the Carpathian(-Balkan) region are recommended to track carefully the spatial domains for which a given, local, proxy-derived hydroclimate reconstruction might provide useful information.

Possibility of identification of negative extreme climatic events using Pinus sylvestris tree-rings in Transdanubia, Hungary

“…The above presented pattern of climate-growth relationship, namely the positive dominance of summer precipitation and negative impact of summer temperature was reported in other studies in Hungary on beech (Garamszegi & Kern, 2014) and on oak (Kern et al, 2013) and was observed many times on pine (Koprowski, 2012;Michelot, 2012;Panayotov et al, 2013;Levanič, 2015;Toromani et al, 2015) as well. However, we found a much unusual pattern also, which has never been observed in Hungary neither on pines nor on other species, but rare in the MJJ (May-June-July), JJA (June-July-August), SPR (March-April-May) and VGP (March-October) represent the combined periods, GWL shows groundwater data.…”

“…Campelo et al, 2007Campelo et al, , 2013Cufar et al, 2011;de Luis et al, 2011;De Micco et al, 2014;Olivar et al, 2012) but researches have already been made in temperate forests as well (Ježík, 2011;Nabais et al, 2014;Panayotov et al, 2013;van der Werf, 2007). Tree-ring studies in Hungary have been focused on climate-growth relationship (Babos, 1984;Garamszegi & Kern, 2014;Kern et al, 2013;Szabados, 2006) and climate reconstruction (Kern et al, 2009) so far, thus dendrochronological approach of the investigation of negative extreme climatic events is still missing.…”

Are carbohydrate storage strategies of trees traceable by early–latewood carbon isotope differences?

“…Due to assimilation, a high coherence is expected between carbon isotopes and air temperature of summer months which is very well-documented by (Kress et al 2009a;Loader et al 2008;Robertson et al 1997), but lower or negative correlations were observed too (Kern et al 2013;Szcepanek et al 2006). These contrasting results are most probably due to the influence of site specific conditions.…”

Growth response of different tree species (oaks, beech and pine) from SE Europe to precipitation over time

“…The response of oaks in the Pannonian lowlands was slightly different to the aforementioned findings. In Slovenia and Hungary, oaks had a narrower window of response; a significant response was found in above average precipitation in the June-July period (Čater & Levanič, 2004;Čufar et al, 2008a;Kern et al, 2013;Levanič et al, 2011). The temperature signal in oak tree-rings has also been tested; it was found to be weak to non-existent.…”