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1. Varying climate signals embedded in latewood blue intensity along an elevational gradient: A multi-species case study from the Great Basin, Nevada, USA

   https://doi.org/10.1016/j.dendro.2025.126366  

   King, Karen E; Cook, Edward R; Krusic, Paul J; King, Daniel J (August 2025, Dendrochronologia)

   As blue intensity (BI) methods are increasingly employed to generate temperature-sensitive tree-ring records around the globe, the influence of intra-site variation in elevation on climate-growth relationships for BI parameters remains largely unresolved. Here, we develop six latewood blue intensity (LWBI) chronologies along an elevational gradient for two montane conifer species, Abies concolor var. concolor (Gordon & Glend.) Lindl. Ex Hilderb and Picea engelmannii Parry ex Engelm., growing in the arid southwestern United States. In this first documented study to examine the climate response of LWBI from A. concolor, we find positive, significant (p < 0.05) correlations between the LWBI chronology from the highest elevation plot and spring–summer temperatures (April–August, r > 0.46). Moreover, the positive temperature response of A. concolor is generally stronger and more temporally stable than for P. engelmannii across varying seasonal windows. In comparing the differences in climate response across species and elevation, we document distinct clinal relationships between the temperature response of LWBI for A. concolor, where both the strength and temporal stability of the positive temperature signal increases with elevation. Meanwhile, the mid-elevation P. engelmannii demonstrate the highest climate sensitivity. As such, our findings contribute to a more comprehensive understanding of how elevation influences the type and strength of the climatic information embedded within the LWBI parameter from arid, montane conifers growing near their historical range margins. 

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2. Tree Rings Reveal the Impact of Soil Temperature on Larch Growth in the Forest-Steppe of Siberia

   https://doi.org/10.3390/f12121765  

   Belokopytova, Liliana V.; Zhirnova, Dina F.; Meko, David M.; Babushkina, Elena A.; Vaganov, Eugene A.; Krutovsky, Konstantin V. (December 2021, Forests)

   Dendroclimatology has focused mainly on the tree growth response to atmospheric variables. However, the roots of trees directly sense the “underground climate,” which can be expected to be no less important to tree growth. Data from two meteorological stations approximately 140 km apart in southern Siberia were applied to characterize the spatiotemporal dynamics of soil temperature and the statistical relationships of soil temperature to the aboveground climate and tree-ring width (TRW) chronologies of Larix sibirica Ledeb. from three forest–steppe stands. Correlation analysis revealed a depth-dependent delay in the maximum correlation of TRW with soil temperature. Temperatures of both the air and soil (depths 20–80 cm) were shown to have strong and temporally stable correlations between stations. The maximum air temperature is inferred to have the most substantial impact during July–September (R = −0.46–−0.64) and early winter (R = 0.39–0.52). Tree-ring indices reached a maximum correlation with soil temperature at a depth of 40 cm (R = −0.49–−0.59 at 40 cm) during April–August. High correlations are favored by similar soil characteristics at meteorological stations and tree-ring sites. Cluster analysis of climate correlations for individual trees based on the K-means revealed groupings of trees driven by microsite conditions, competition, and age. The results support a possible advantage of soil temperature over air temperature for dendroclimatic analysis of larch growth in semiarid conditions during specific seasons. 

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3. Reconstructed Late Summer Maximum Temperatures for the Southeastern United States From Tree‐Ring Blue Intensity

   https://doi.org/10.1029/2024GL109099  

   King, Karen E; Harley, Grant L; Maxwell, Justin T; Rayback, Shelly; Cook, Edward; Maxwell, R Stockton; Rochner, Maegen L; Bergan, Ellen V; Foley, Zachary; Therrell, Matthew; et al (July 2024, Geophysical Research Letters)

   Abstract Over recent decades, the southeastern United States (Southeast) has become increasingly well represented by the terrestrial climate proxy record. However, while the paleo proxy records capture the region's hydroclimatic history over the last several centuries, the understanding of near surface air temperature variability is confined to the comparatively shorter observational period (1895‐present). Here, we detail the application of blue intensity (BI) methods on a network of tree‐ring collections and examine their utility for producing robust paleotemperature estimates. Results indicate that maximum latewood BI (LWBI) chronologies exhibit positive and temporally stable correlations (r = 0.28–0.54,p < 0.01) with summer maximum temperatures. As such, we use a network of LWBI chronologies to reconstruct August‐September average maximum temperatures for the Southeast spanning the period 1760–2010 CE. Our work demonstrates the utility of applying novel dendrochronological techniques to improve the understanding of the multi‐centennial temperature history of the Southeast. 

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4. Changing climate response of Northeast Ohio white oaks, USA: Is it tree age or site age?

   Wiles, G; Wiesenberg, N; Pollock, M; Denes, C; Cooper, T; Smith, D; Wiles, M (February 2025, Dendrochronologia)

   White oak, a keystone species of the broadleaf forests of the North American Midwest, has a significant role in providing ecosystems services in a region experiencing warming and increasingly pluvial conditions. A one- hundred-year-old white oak stand in an arboretum, along with two second growth (~200-year-old) stands from Northeast Ohio have consistently responded positively to summer (June-July) precipitation over the past century, whereas four nearby old growth sites (>300 years old) have lost their moisture sensitivity since about the mid 1970s. This “fading drought signal,” which has been previously reported, appears to be more a result of the legacy of land use at the individual sites rather than tree age. The younger oak stands and their relative sustained drought sensitivity is also related to their history of recently attaining the canopy and similar responses associated with intervals of selective logging. All sites are strongly, negatively correlated with summer (June- July) maximum monthly temperatures and in general the maximum temperatures are negatively correlated with precipitation in those months. Future warming in the Midwest is projected to see increases in spring precipitation and likely decreases in late summer precipitation linked to a northward migration of the North American Westerly Jet. This projected decrease in summer precipitation coupled with an increase in maximum and min- imum summer temperatures in the coming decades would increase the moisture stress on these trees. Our ex- amination of these varying climate responses with respect to site characteristics and forest age can help future assessments of tree health and the forest’s ability to sequester carbon, as well as facilitate efforts to reconstruct climate by using a range of tree sites for intervals when sensitivity in old growth sites is lost. 

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5. A comparison of the climate response of longleaf pine (Pinus palustris Mill.) trees among standardized measures of earlywood, latewood, adjusted latewood, and totalwood radial growth

   https://doi.org/https://doi.org/10.1007/s00468-021-02093-z  

   Soule', P.T.; Knapp, P.A.; Maxwell, J.T.; and Mitchell, T.J. (April 2021, Trees)

   null (Ed.)

   Our objective was to examine broadly the climate–growth responses of longleaf pine (Pinus palustris Mill.) on the Coastal Plain province of North and South Carolina to temperature, precipitation, and drought severity. We compared the responses between standardized earlywood, latewood, adjusted latewood, and totalwood radial tree growth. We sampled mature longleaf pine growing in open-canopy savanna environments and developed six tree-ring chronologies using standard dendroecological techniques. We used a combination of Pearson correlation, moving interval correlation, and Fisher r–z tests to determine which monthly and seasonal variables were most closely related to radial growth, the temporal stability of the dominant growth/climate relationship, and whether earlywood and latewood growth provide signifcantly diferent climate responses. Our results show that the strongest relationships with climate are with adjusted latewood growth and that rainfall in the later parts of the growing season (i.e., July–September) is the primary control of radial growth. Spatially, we found that growth/climate responses were similar throughout the Coastal Plain region encompassing the six study sites. Temporally, we found that July–September precipitation produced signifcant (p<0.05) relationships with radial growth for extended annual intervals, but there were shorter periods when this relationship was non-signifcant. In general, growth/ climate relationships were stronger for latewood compared to earlywood, and these responses were signifcantly (p<0.05) diferent at about half of our study sites. Our fndings are congruent with prior research in this region showing that shortduration precipitation events are a critical component for radial growth. Further, these results emphasize the importance of latewood growth—particularly adjusted latewood growth—in capturing interannual climate/growth responses. 

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