Dendroclimatic studies on conifers from central Europe and Great Britain

Abstract

Ernst 1979 1201: Dendroclimatic studieson conifers from central Europe and Great Britain. Boreas, Vol. 8, pp. 427452. Oslo. ISSN 0300-9483.The use of X-ray densitometry for measuring tree rings makes it possible to consider the relations between climate and tree rings in a new light. Investigations so far have shown that it is the maximum density of the annual rings that provides the most important and best climatological information. Comparisons between density sequences are possible when the tree-ring samples come from ecologically similar sites. Site characteristics are expressed by six different tree-ring parameters. Relations between the maximum densities of various species from different regions are revealed by calculating the percentage of agreement. The growth rate of cell walls in latewood of all coniferous species from cool humid regions is limited mainly by summer temperatures. In Scotland, where the climate is cool-oceanic and relatively stable, the cell walls grow from June to October. In the subalpine zone of the Alps and the Rocky Mountains near the timber line growth takes place mainly in August and September. Maximum density in trees of temperate sites is also primarily influenced by the summer temperature. Minimum density shows the relationship to the xerothermic site characteristics. On dry sites cambial activity and cell wall growth in latewood are mainly limited by precipitation during the growth period.Samples from the subalpine zones (1500-2200 rn above sea level) between latitudes 45" and 50" North, i.e. those from the Western Carpathians, the Alps, and the Northern Appalachian Mountains, seem to form a unity. Samples from the oceanic region (20-600 m above sea level) between 52" and 58"N latitudes show a different and incoherent picture. Only the present low level density during 1950-1975 is evident at all sites investigated for the last 200 years.By cross-dating the annual tree-ring sequences of living trees with samples of timber taken from ancient houses a 700-year-long chronology has been developed for the Northern Prealps in Switzerland. This chronology shows the approximate annual and decennial temperature changes; the sensitivity curve shows the different climatic variability in temperature. FritzH . Schwingrubi,r. Otto U. Brukiv-und Ernst Sc,har. Sn.is.s F i , d i d Institute ofFurc,stry R1,jiwri.h. CH-8W3 Birmivwdorf. Swirzcrlund; 30th Novrrnhi,r. IY78 (rrvised 16th Muy. 1979).

Low‐frequency noise in δ13C and δ18O tree ring data: A case study of Pinus uncinata in the Spanish Pyrenees

“…High‐resolution studies on shorter time series revealed evidence for systematic differences between stable isotope values derived from earlywood and latewood samples, and steep intra‐annual gradients [ Helle and Schleser , 2004; Schulze et al , 2004]. Such changes within single tree rings could also influence the herein identified δ 18 O and δ 13 C age trends, as the ratios of earlywood‐to‐latewood widths [ Fritts , 1976] and their densities [ Schweingruber et al , 1978] often change slightly over the trees lifespan. Other work, however, indicated that differences between latewood and whole ring samples are restricted to deciduous trees, where earlywood formation is dominated by the mobilization of reserves [ Barbour et al , 2002; Hill et al , 1995], while conifers show a high degree of coherence between early and latewood isotope values [ Kress et al , 2009].…”

Five centuries of Central European temperature extremes reconstructed from tree-ring density and documentary evidence

“…Numerous studies have shown that radial growth and wood density of conifers varies under the influence of temperature (e.g., Fritts, 1976;Schweingruber et al, 1979). A cool and short growing season results in a narrow ring with low-density latewood (Hantemirov et al, 2004), whereas more favorable warmer conditions lead to wider rings with higher MXD .…”

Climate change and human activities: a case study in Xinjiang, China

“…Reconstruction periods vary from 203 to 291 years based on time span of available chronologies climate in a specific year may affect tree-ring width (TRW) in one or more subsequent years (Fritts 1976), so a 1-year lag was also considered in our reconstruction. Based on the correlation between WI n and TRW n /TRW n+1 , we then established a transfer function by regressing tree-ring data against instrumental record (Fritts 1976;Schweingruber et al 1979). Combining autocorrelation and maximum likelihood methods (SAS 8.0, SAS Institute Inc., Cary, NC, USA), a regression model was developed and fed with proxy data to reconstruct past climate.…”