Dendroclimatic Response Variability of Quercus species in the Romanian Intensive Forest Monitoring Network

Abstract

Oaks are among the most important broad-leaved species in Romanian forests from both an economic and socio-ecological point of view. A significant decline of these species has been observed, which was first evident in various studies and investigations followed by the more results of interdisciplinary research performed in intensive monitoring plots (level II) showing that the decline is climate induced. Thus, it is important to understand the climate change conditions and factors that influence Quercus spp. Typical dendroclimatological investigations were conducted on an intensive forest monitoring network based on four oak species (Q. robur, Q. petraea, Q.cerris, and Q. frainetto) in 7 permanent plots placed in southern Romania. Three patterns of climate-growth relationships were identified and discerned in accordance with the Quercus species. All oak species were found to have a positive correlation with the level of precipitation. In addition, the intensity and level of significance of correlation coefficients differ from one species to another and from one region to another.

Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus Petraea) in the Czech Republic

“…Some of the characteristics also manifested significant correlations in July, August, and September ( Table 3). The significant positive effect of precipitation in May and June has also been proven by a number of European dendroclimatological and xylogenetic studies dealing with the sessile oak in France (Becker et al, 1994;Lebourgeois et al, 2004;Mérian et al, 2011;Michelot et al, 2012), Romania (Popa et al, 2013), Germany (Friedrichs et al, 2009), Slovakia (Petráš andMecko, 2011), Poland (Cedro, 2007;Bronisz et al, 2012), and Moravia, Czech Republic (Doležal et al, 2010). The negative effect of June (or July) temperatures has also been demonstrated repeatedly (Doležal et al, 2010;Mérian et al, 2011;Petráš and Mecko, 2011;Michelot et al, 2012).…”

Recent growth coherence in long-term oak (Quercus spp.) ring width chronologies in the Czech Republic

“…This has been demonstrated by CZ oaks before (Doležal et al 2010), and positive response to summer precipitation has also been shown for oak chronologies from France (Mérian et al 2011), Romania (Popa et al 2013), Germany (Friedrichs et al 2009a), Slovakia (Petráš &Mecko 2011), andPoland (Bronisz et al 2012). However, responses to hydroclimate in the Czech Re public were quite weak and unstable over time.…”

Methods for Quantification of the Decline Phenomenon and Determination of the Vulnerability Degree for the Oak Stands in Northwestern Transylvania, Romania

“…The negative impact on forests of environmental factors was, in Romania, similar to the one described in most European countries, and there existed numerous situations in which devitalization, deterioration of vegetation state and occurrence of abnormal diebacks started to become frequent (Rossnev et al, 1994;Woo, 2009;Sonesson and Drobyshev, 2010;Popa et al, 2013;Jankowiak et al, 2014;Keca et al, 2016).…”