An improved understanding of the spatiotemporal climate/growth relationship of our forests is of particular importance for assessing the consequences of climate warming. A total of 67 stands of beech (Fagus sylvatica L.), pedunculate oak (Quercus robur L.), sessile oak (Quercus petraea (Matt.) Liebl.), Scots pine (Pinus sylvestris L.), and spruce (Picea abies Karst.) from sites located in the transition zone from the lowlands to the low mountain ranges of West Germany have been analysed. A combination of pointer year and cluster analysis was used to find groups with similar growth anomaly patterns over the 1941–2000 period. Shifted reaction patterns especially characterise differences in the growth behaviour of the clusters. These are controlled by different reactions to the climate conditions in winter and spring and are determined by a complex system of forcing factors. Results of this study reflect the enormous importance of the length of the growing season. Increasing the duration of the vegetation period climate warming can change the climate/growth relationship of trees, thereby confounding climate reconstructions which use tree rings. Since forcing factors have been detected that are more important than the tree species, we recommend the application of growth-specific approaches for the analysis of tree species’ vulnerability to climate. 1. Introduction Whereas tree growth at the timberline is mostly limited by only one specific dominant factor [1], growth of temperate forest regions is influenced by a multitude of biotic and abiotic factors [2–4]. This is caused by predominant temperate climate conditions and the fact that mostly native tree species are growing in the range of their natural distribution areas [5]. Nevertheless, climate control is still a crucial forcing factor for annual tree-ring growth in lower altitudes [3]. The 20th century warming trends are extraordinary [6] and steady since the late 1970s [7] and have lengthened the duration of the growing season [8]. An increase of severe climate extremes such as heat waves is inherent with these [9], whereas changes in precipitation and dryness extremes are less clearly linked [10]. However, a better understanding of the spatiotemporal climate/growth relationships, including the identification of the environmental drivers, is of particular importance [11–13] to understand climate-induced changes in forest productivity with regard to different tree species and site characteristics. Previous studies have shown that analyses of tree-ring width at lower elevation sites are suitable for
References
[1]
C. K？rner, “A re-assessment of high elevation treeline positions and their explanation,” Oecologia, vol. 115, no. 4, pp. 445–459, 1998.
[2]
H. C. Fritts, Tree Rings and Climate, Academic Press, London, UK, 1976.
[3]
F. H. Schweingruber, Tree Rings and Environment. Dendroecology, Paul Haupt, Stuttgart, Germany, 1996.
[4]
D. A. Friedrichs, U. Büntgen, J. Esper, D. C. Frank, B. Neuwirth, and J. L？ffler, “Complex climate controls on 20th century oak growth in central-west Germany,” Tree Physiology, vol. 29, pp. 39–51, 2009.
[5]
H. Ellenberg, Die Vegetation Mitteleuropas mit den Alpen in ？kologischer, dynamischer und historischer Sicht, Ulmer, Stuttgart, Germany, 5th edition, 1996.
[6]
D. C. Frank, J. Esper, C. C. Raible et al., “Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate,” Nature, vol. 463, no. 7280, pp. 527–530, 2010.
[7]
G. Foster and S. Rahmstorf, “Global temperature evolution 1979–2010,” Environmental Research Letters, vol. 6, pp. 1–8, 2011.
[8]
T. E. Skaugen and O. E. Tveito, “Growing-season and degree-day scenario in Norway for 2021–2050,” Climate Research, vol. 26, pp. 221–232, 2004.
[9]
M. Stefanon, F. D’Andrea, and P. Drobinski, “Heatwave classification over Europe and the Mediterranean region,” Environmental Research Letters, vol. 7, pp. 1–9, 2012.
[10]
B. Orlowsky and S. I. Seneviratne, “Global changes in extreme events: regional and seasonal dimension,” Climatic Change, vol. 110, pp. 669–696, 2012.
[11]
K. R. Briffa, T. J. Osborn, F. H. Schweingruber, P. D. Jones, S. G. Shiyatov, and E. A. Vaganov, “Tree-ring width and density data around the Northern Hemisphere: part 2, spatio-temporal variability and associated climate patterns,” The Holocene, vol. 12, no. 6, pp. 759–789, 2002.
[12]
B. Neuwirth, F. H. Schweingruber, and M. Winiger, “Spatial patterns of central European pointer years from 1901 to 1971,” Dendrochronologia, vol. 24, no. 2-3, pp. 79–89, 2007.
[13]
L. DeSoto, J. J. Camarero, J. M. Olano, and V. Rozas, “Geographically structured and temporally unstable growth responses of Juniperus thurifera to recent climate variabilityin the Iberian Peninsula,” European Journal of Forest Research, vol. 131, pp. 905–917, 2012.
[14]
C. Dittmar and W. Elling, “Jahrringbreite von Fichte und Buche in Abh？ngigkeit von Witterung und H？henlagen,” Forstwissenschaftliches Centralblatt, vol. 118, pp. 251–270, 1999.
[15]
S. Bonn, “Dendro？kologische Untersuchung der Konkurrenzdynamik in Buchen-Eichen-Mischbest？nden und zu erwartende Modifikationen durch Klima？nderungen,” Forstwissenschaftliche Beitr？ge, vol. 3, Dresden, Germany, 1998.
[16]
D. A. Friedrichs, V. Trouet, U. Büntgen et al., “Species-specific climate sensitivity of tree growth in Central-West Germany,” Trees, vol. 23, pp. 729–739, 2009.
[17]
D. A. Friedrichs, B. Neuwirth, M. Winiger, and J. L？ffler, “Methodologically induced differences in oak site classifications in a homogeneous tree-ring network,” Dendrochronologia, vol. 27, no. 1, pp. 21–30, 2009.
[18]
F. H. Schweingruber and P. Nogler, “Synopsis and climatological interpretation of Central European tree-ring sequences,” Botanica Helvetica, vol. 113, no. 2, pp. 125–143, 2003.
[19]
F. Babst, M. Carrer, C. Urbinati, B. Neuwirth, and D. Frank, “500 years of regional forest growth variability and links to climatic extreme events in Europe,” Environmental Research Letters, vol. 7, no. 4, Article ID 045705, 2012.
[20]
F. H. Schweingruber, D. Eckstein, F. Serre-Bachet, and O. U. Br？ker, “Identification, presentation and interpretation of event years and pointer years in dendrochronology,” Dendrochronologia, vol. 8, pp. 9–38, 1990.
[21]
S. Z’Graggen, Dendrohistometrisch-klimatologische Untersuchung an Buchen (Fagus sylvatica L.) [Ph.D. thesis], Universit？t Basel, 1992.
[22]
M. Kaennel and F. H. Schweingruber, Eds., Multilingual Glossary of Dendrochronology, Birmensdorf, Swiss Federal Institute for Forest, Snow and Landscape Research. Paul Haupt, Stuttgart, 1995.
[23]
J. W. Hurrel, Y. Kushnir, G. Ottersen, and M. Visbeck, “An overview of the North Atlantic Oscillation. Climatic significance and environmental impact,” Geophysical Monograph, vol. 134, pp. 1–35, 2003.
[24]
R. Schulz and N. Asche, “Klima, Standort, Wald. Regionales Wasserhaushaltsmodell auf Bundesebene übertragbar ?” AFZ-DerWald, vol. 1, pp. 20–24, 2008.
[25]
B. Neuwirth, “Jahrringe als Indikator für Klima- und Umweltver？nderungen in Mitteleuropa,” Passauer Kontaktstudium Geographie, vol. 11, pp. 67–78, 2011.
[26]
S. Fischer and B. Neuwirth, “Klimasensitivit？t der Douglasie in Eifel und Kellerwald,” Allgemeine Forst- und Jagdzeitung, vol. 183, pp. 23–33, 2012.
[27]
J. Schultz and B. Neuwirth, “A new atmospheric circulation tree-ring index (ACTI) derived from climate proxies: procedure, results and applications,” Agricultural and Forest Meteorology, vol. 164, pp. 149–160, 2012.
[28]
U. Schulte and A. Scheible, Atlas der Naturwaldzellen in Nordrhein-Westfalen,, B.o.s.s. Druck und Medien, Kleve, Germany, 2005.
[29]
M. A. Stokes and T. L. Smiley, An Introduction To Tree-Ring Dating, University of Arizona Press, Tucson, Ariz, USA, 1968, reprinted 1996.
[30]
J. R. Pilcher, “Sample preparation, cross-dating and measurement,” in Methods of Dendrochronology. Applications in the Environmental Sciences, E. R. Cook and L. A. Kairiukstis, Eds., pp. 40–51, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1990.
[31]
F. Rinn, “TSAP-Win. Time series analysis and presentation for dendrochronology and related applications,” Version 0.53 for Microsoft Windows. User Reference, Heidelberg, Germany, 2003.
[32]
R. L. Holmes, “Computer-assisted quality control in tree-ring dating and measurement,” Tree-Ring Bulletin, vol. 43, pp. 69–78, 1983.
[33]
J. Esper, B. Neuwirth, and K. Treydte, “A new parameter to evaluate temporal signal strength of tree-ring chronologies,” Dendrochronologia, vol. 19, pp. 93–102, 2001.
[34]
K. R. Briffa and P. D. Jones, “Basic chronology statistics and assessment,” in Methods of Dendrochronology: Applications in the Environmental Sciences, E. R. Cook and L. A. Kairiukstis, Eds., pp. 137–152, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1990.
[35]
T. M. L. Wigley, K. R. Briffa, and P. D. Jones, “On the average value of correlated time series with applications in dendroclimatology and hydrometeorology.,” Journal of Climate & Applied Meteorology, vol. 23, no. 2, pp. 201–213, 1984.
[36]
T. D. Mitchell and P. D. Jones, “An improved method of constructing a database of monthly climate observations and associated high-resolution grids,” International Journal of Climatology, vol. 25, no. 6, pp. 693–712, 2005.
[37]
J. P. Cropper, “Tree-ring skeleton plotting by computer,” Tree-Ring Bulletin, vol. 39, pp. 47–59, 1979.
[38]
B. Neuwirth, Klima/Wachstums-Beziehungen zentraleurop？ischer B？ume von 1901 bis 1971—Eine dendroklimatologische Netzwerkanalyse [Ph.D. thesis], Universit？t Bonn, 2005.
[39]
M. Koprowski and A. Zielski, “Dendrochronology of Norway spruce (Picea abies (L.) Karst.) from two range centres in lowland Poland,” Trees, vol. 20, no. 3, pp. 383–390, 2006.
[40]
I. Leyer and K. Wesche, Multivariate Statistik in der ？kologie, Springer, Heidelberg, Germany, 2007.
[41]
G. Bahrenberg, E. Giese, and J. Nipper, Statistische Methoden in der Geographie 2: Multivariate Statistik, Borntraeger, Berlin, Germany, 2nd edition, 2003.
[42]
H. G. Hidalgo, J. A. Dracup, G. M. MacDonald, and J. A. King, “Comparison of tree species sensitivity to high and low extreme hydroclimatic events,” Physical Geography, vol. 22, no. 2, pp. 115–134, 2001.
[43]
B. Neuwirth, D. Friedrichs, and M. Hennen, “2003—where is the negative pointer year? A case study for the NW-German low mountain ranges,” Tree Rings in Archaeology, Climatology and Ecology, vol. 5, pp. 113–120, 2007.
[44]
F. Lebourgeois and E. Ulrich, “Forest trees phenology in the French Permanent Plot Network (Renecofor, ICP forest network),” in Forests, Carbon Cycle and Climate Change, D. Lousteau, Ed., pp. 158–171, Collection UpDateSciences and Technologies, 2010.
[45]
A. Menzel, G. Jakobi, R. Ahas, H. Scheifinger, and N. Estrella, “Variations of the climatological growing season (1951–2000) in Germany compared with other countries,” International Journal of Climatology, vol. 23, no. 7, pp. 793–812, 2003.
[46]
E. R. Cook, M. A. Kablack, and G. C. Jacoby, “The 1986 drought in the southeastern United States: how rare an event was it?” Journal of Geophysical Research, vol. 93, no. 11, pp. 14–260, 1988.
[47]
F. Babst, B. Poulter, V. Trouet et al., “Site and species-specific responses of forest growth to climate across the European continent,” Global Ecology and Biogeography. In press.
[48]
K. R. Briffa, F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov, and E. A. Vaganov, “Reduced sensitivity of recent tree-growth to temperature at high northern latitudes,” Nature, vol. 391, no. 6668, pp. 678–682, 1998.
[49]
J. Bergh, S. Linder, and J. Bergstr？m, “Potential production of Norway spruce in Sweden,” Forest Ecology and Management, vol. 204, pp. 1–10, 2005.
[50]
H. Wachter, “über die Beziehung zwischen Witterung und Buchenmastjahren,” Forstarchiv, vol. 35, pp. 69–78, 1964.
[51]
C. Dittmar, W. Zech, and W. Elling, “Growth variations of Common beech (Fagus sylvatica L.) under different climatic and environmental conditions in Europe—A dendroecological study,” Forest Ecology and Management, vol. 173, no. 1–3, pp. 63–78, 2003.
[52]
H. Oswald, “Importance et périodicité des fa？nées. Influence des facteurs climatiques et sylvicoles,” in Le Hêtre, E. Teissier du Cros, F. Le Tacon, G. Nepveu, J. Pardé, R. Perrin, and J. Timbal, Eds., pp. 207–241, Paris, France, 1981.
[53]
V. Sel？s, G. Piovesan, J. M. Adams, and M. Bernabei, “Climatic factors controlling reproduction and growth of Norway spruce in southern Norway,” Canadian Journal of Forest Research, vol. 32, no. 2, pp. 217–225, 2002.
[54]
M. Mund, W. L. Kutsch, C. Wirth et al., “The influence of climate and fructification on the inter-annual variability of stem growth and net primary productivity in an old-growth, mixed beech forest,” Tree Physiology, vol. 30, no. 6, pp. 689–704, 2010.
[55]
H. P. M？kinen, N. Mielik？inen, and K. Mielik？inen, “Climatic signal in annual growth variation of Norway spruce (Picea abies) in southern Finland,” Trees, vol. 15, pp. 177–185, 2001.
[56]
J. H. Bassman, G. E. Edwards, and R. Robberecht, “Long-term exposure to enhanced UV-B radiation is not detrimental to growth and photosynthesis in Douglas-fir,” New Phytologist, vol. 154, no. 1, pp. 107–120, 2002.
