This paper presents a method for classification of trees in groups depending on parameters of the age trend in tree-ring width. The method is tested on a sample containing 194 trees of Scots pine (Pinus sylvestris L.) growing in the forest-steppe zone of the South of Central Siberia. The climatic response of tree-ring width in such climatic conditions is complex. The influence of temperature in May-September is negative (moisture reducing). Warm-season precipitation serving as a source of moisture is a positive factor. Another positive factor is cold-season precipitation as frost protection. We determined the dependence of this response on the local conditions (soil, landscape and anthropogenic factors). The competitive strength of the trees influences both the sensitivity of individual trees to extreme climatic factors and the timing of growth processes. The latter implies the duration of the period of significant response to climate. It appears promising to take this influence into account in dendroclimatic reconstructions by using separate clusters of trees based on the competitive strength and having the maximum response to the reconstructed factor.

This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at editor@treeringsociety.org.

The long generation time of woody plants inhibits detection of shifts in their distributions induced by climatic change. Consequently, assessing growth changes within existing populations, especially those near species range margins, can increase understanding of climate change impacts. We apply dendrochronological methods to examine recent radial growth of the ecologically similar species Juniperus communis L. and J. virginiana L. growing under the same conditions but at opposite latitudinal range margins. We use moving correlations to analyze changes in relationships between growth and monthly climatic variables, and regional curve standardization to identify trends in growth rate independent of plant age. For J. communis, growth sensitivity to temperature and precipitation shifted earlier in the spring whereas for J. virginiana only temperature sensitivity shifted earlier over the last 50 years. Since 1920, J. virginiana growth displays an upward trend, but J. communis growth shows both increases and decreases. Recent precipitation increase, rather than warming alone, appears to drive the growth trends, but interactions with temperature and vegetation dynamics, instead of range position, likely account for the differences in trends between species. Although these results generally agree with climate change predictions, they also point out potential difficulties in modeling future species ranges based on growth-climate relationships and growth at range margins.

Abstract This report describes an international summer course, “Tree Rings, Climate, Natural Resources, and Human Interaction”, held in Valsain, Spain, in summer of 2012. The course, with 14 participants from three countries (Spain, Algeria, and Russia), included basic training in dendrochronology skills as well as applied projects in dendroclimatology, dendroecology and dendrogeomorphology.

There are at least 21 dendro-data formats used in dendrochronology laboratories around the world. Many of these formats are read by a limited number of programs, thereby inhibiting collaboration, limiting critical review of analyses, and risking the long-term accessibility of datasets. Some of the older formats are supported by a single program and are falling into disuse, opening the risk for data to become obsolete and unreadable. These formats also have a variety of flaws, including but not limited to no accurate method for denoting measuring units, little or no metadata support, lack of support for variables other than whole ring widths (e.g. earlywood/latewood widths, ratios and density). The proposed long-term solution is the adoption of a universal data standard such as the Tree-Ring Data Standard (TRiDaS). In the short and medium term, however, a tool is required that is capable of converting not only back and forth to this standard, but between any of the existing formats in use today. Such a tool is also required to provide continued access to data archived in obscure formats. This paper describes TRiCYCLE, a new application that does just this. TRiCYCLE is an open-source, cross-platform, desktop application for the conversion of the most commonly used data formats. Two open source Java libraries upon which TRiCYCLE depends are also described. These libraries can be used by developers to implement support for all data formats within their own applications.

Abstract Coast redwood (Sequoia sempervirens) ecosystems are strongly influenced by the presence of summer marine fog, and variation in fog frequency is closely linked to climate variation in the NE Pacific region. Because oxygen isotope composition (δ18O) of organic matter records distinct water sources (e.g. summertime fog vs. winter precipitation) and carbon isotopes (δ13C) are typically sensitive to humidity and water status, it then follows that inter-annual variation in tree-ring isotope ratios, which are coherent across multiple sites, should preserve a potentially powerful proxy for climate reconstruction. Here we present an analysis of a 50-year time series for both δ18O and δ13C values from subdivided tree rings obtained from multiple redwood trees at multiple sites. Within-site and between-site correlations were highly significant (p < 0.01) for the δ18O time series indicating a regionally coherent common forcing of δ18O fractionation. Within-site and between-site correlation coefficients were ...