Long-term temporal changes in central European tree phenology (1946−2010) confirm the recent extension of growing seasons

Abstract

One of the ways to assess the impacts of climate change on plants is analysing their long-term phenological data. We studied phenological records of 18 common tree species and their 8 phenological phases, spanning 65 years (1946-2010) and covering the area of the Czech Republic. For each species and phenophase, we assessed the changes in its annual means (for detecting shifts in the timing of the event) and standard deviations (for detecting changes in duration of the phenophases). The prevailing pattern across tree species was that since around the year 1976, there has been a consistent advancement of the onset of spring phenophases (leaf unfolding and flowering) and subsequent acceleration of fruit ripening, and a delay of autumn phenophases (leaf colouring and leaf falling). The most considerable shifts in the timing of spring phenophases were displayed by early-successional short-lived tree species. The most pronounced temporal shifts were found for the beginning of seed ripening in conifers with an advancement in this phenophase of up to 2.2 days year⁻¹ in Scots Pine (Pinus sylvestris). With regards to the change in duration of the phenophases, no consistent patterns were revealed. The growing season has extended on average by 23.8 days during the last 35 years. The most considerable prolongation was found in Pedunculate Oak (Quercus robur): 31.6 days (1976-2010). Extended growing season lengths do have the potential to increase growth and seed productivity, but unequal shifts among species might alter competitive relationships within ecosystems.

Differences in the environmental control of leaf senescence of four Quercus species coexisting in a Mediterranean environment

“…Nevertheless, bearing in mind the observed differences, it is clear that the possible implications of climate change will differ from one species to another. According to the present results, the foreseen rise in temperatures would lead to advances in emergence and delays in abscission of deciduous leaves (Gordo & Sanz, 2009;García-Mozo et al, 2010;Kolářová et al, 2014) thereby increasing the duration of the growth season in deciduous species. Additionally, if drought boosts leaf mortality, as seem to be apparent from the present study, at least in Q. ilex, we can expect to see a more marked summer leaf abscission in this species in response to the decrease in water availability.…”

“…In contrast, temperature is revealed in most cases as one of the most important factors affecting phenology, higher temperatures contributing to advance the date of leaf emergence (Morin et al, 2010;Wielgolaski et al, 2011;Cook et al, 2012). This has led to predict an increase in the length of the growing season due to global warming, with a consequent increase in forest productivity (Gordo & Sanz, 2005Richardson et al, 2009;Kolářová et al, 2014). Less conclusive is, however, the analysis of the effects of different environmental factors on leaf senescence; therefore the possible changes of this phenological event in response to global warming are less predictable.…”

Extreme winter warm event causes exceptionally early bud break for many woody species

“…Because shade tolerance is often related to successional stage (i.e., fast‐growing, short‐lived, and early‐successional species are shade‐intolerant and break dormancy before slow‐growing, long‐lived, and late‐successional species; Kolářová et al. , Tang et al. ), many early‐successional species also have dormancy requirements related to accumulation of GDD rather than photoperiod (Caffarra and Donnelly , Basler and Körner , Zohner et al.…”

Hamburger Klimabericht – Wissen über Klima, Klimawandel und Auswirkungen in Hamburg und Norddeutschland

“…In den mittleren Breiten der Nordhalbkugel ergibt sich dadurch insgesamt eine Verlängerung der Vegetationsperiode um 14-24 Tage in den letzten 5-7 Jahrzehnten (vgl. Menzel 2013; Kolářová et al 2014;Schuster et al 2014), die mit anderen Proxydaten (z. B. Vegetationsindizes aus Satellitenbildern, Jahresgang des CO 2 -Gehaltes der Atmosphäre) und abiotischen Signalen (z.…”