Valerie M Trouet

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Courses

Scholarly Contributions

Books

• Trouet, V. M. (2020). Tree story: The history of the world written in rings. Johns Hopkins University Press.
• Trouet, V. M. (2020). Wat bomen ons vertellen. Tielt, Belgium: Lannoo.

Chapters

• Trouet, V. M. (2020). Klimaatverandering in de context van de laatste 1000 jaar: wat we weten vanuit dendrochronologie. In Lessen voor de eenentwintigste eeuw: Wetenschap in een veranderende wereld(p. 308). Leuven University Press.
• Trouet, V. M., Dominguez-Delmas, M., Pearson, C. L., Pederson, N., & Darin, R. (2017). Dendro-archeo-ecology in North America and Europe: Re-purposing Historical Materials to Study Ancient Human-Environment Interactions. In Dendroecology: Tree-ring analyses applied to ecological studies(pp 365-394). Springer.

Journals/Publications

• Kuhl, E., Esper, J., Trouet, V. M., & al, e. (2024). Incomparably strong cooling in the wake of the Samalas eruption 1257 CE: Improving pitfalls of reconstruction methods enables better understanding of high-frequency temperature variation in Western Europe.  . Climate Dynamics.
• McDonald, G., co-authors, 1., & Trouet, V. M. (2023). Drivers of California’s changing wildfires: a state-of-the-knowledge synthesis. . International Journal of Wildland Fire. doi:doi.org/10.1071/WF22155
• Chen, F., Yuan, Y., Trouet, V. M., & co-authors, 9. (2022). Ecological and societal effects of Central Asian streamflow variation over the past eight centuries. NPJ Climate & Atmospheric Science.
• Dorado-Liñan, I., Ayarzaguena, B., Babst, F., Xu, G., co-authors, 5., & Trouet, V. M. (2022). Jet stream position explains regional anomalies in European forest productivity. Nature Communications.
• Hu, H., Trouet, V. M., & co-authors, 1. (2022). Split westerlies over Europe in the early Little Ice Age.  . Nature Communications. doi:doi.org/10.1038/s41467-022-32654-w
• Hu, H., Trouet, V. M., & co-authors, 2. (2022). Multiscale northern westerlies drift in Europe since the middle Holocene. Nature Communications.
• Hudson, A., Smith, W. K., Moore, D. J., & Trouet, V. M. (2022). Length of growing season is modulated by Northern Hemisphere jet stream variability.. International Journal of Climatology.
• Margolis, E., Guiterman, C., Chavardes, R., Trouet, V. M., & co-authors, 1. (2022). The North American tree-ring fire-scar network. Ecosphere.
• Ols, C., DeRose, R. J., Girardin, M. P., Evans, M. E., Klesse, S., & Trouet, V. M. (2023). Tree growth-climate relationships: should we detrend the explanatory variables?. Dendrochronologia.
• Sahan, e., Trouet, V. M., & co-authors, 5. (2022).

  Multi-century spatiotemporal patterns of fire history in black pine forests, Turkey.

  . Forest Ecology and Management. doi:doi.org/10.1016/j.foreco.2022.120296
• Trouet, V. M., Wang, Z., Huang, R., Yao, Q., Zheng, B., & Zhang, G. (2023). Strong wind drives grassland fire in China. Environmental Research Letters.
• U'Ren, J., Oita, S., Lutzoni, F., Miadlikowska, J., Ball, B., co-authors, 4., Trouet, V. M., & Arnold, A. E. (2024). Host-specific responses to climate define symbioses in boreal forests. Current Biology.
• Xu, G., Liu, X., Hu, J., Dorado-Linan, I., Gagen, M., Chen, t., & Trouet, V. M. (2020). Intra-annual tree-ring d18O and d13C as ecophysiological indicators in humid subtropical China. Tree Physiology.
• Xu, G., co-authors, 6., & Trouet, V. M. (2022). Intra-annual tree-ring d18O and d13C reveal a trade-off between isotopic source and humidity in moist environments. . Tree Physiology.
• Yao, Q., co-authors, 8., & Trouet, V. M. (2024). North Atlantic Oscillation modulates the interplay between monsoon and westerlies in Asia on interdecadal timescales. Climate Dynamics.
• Zamora-Reyes, D., Black, B., & Trouet, V. M. (2022). Enhanced winter, spring, and summer hydroclimate variability across Califronia from 1940 to 2019. International Journal of Climatology.
• Zamora-Reyes, D., Meko, D. M., Black, B., Woodhouse, C. A., & Trouet, V. M. (2022).

  The unprecedented character of California’s 20th century enhanced hydroclimatic variability placed in a 600-year context

  . Geophysical Research Letters. doi:doi.org/10.1029/2022GL099582
• Zuidema, P., Babst, F., Groenendijk, P., Trouet, V. M., & co-authors, 9. (2022). Dry-season climate drives interannual variability in tropical tree growth.. Nature Geoscience.
• yao, q., zhen, b., wang, x., Hudson, a., & Trouet, V. M. (2024). Climate change is a driver of the rising urban fire activity in China. National Science Review.
• Büntgen, U., co-authors, 3., Anchukaitis, K. J., Hughes, M. K., Trouet, V. M., Xu, G., & Esper, J. (2021). The influence of decision-making in tree ring-based climate reconstructions. Nature Communications.
• Fang, K., Yao, Q., Guo, Z., Zheng, B., Du, J., Yan, P., Qi, F., Ou, T., Liu, J., Li, J., He, M., & Trouet, V. (2021). ENSO modulates wildfire activity in China.. Nature Communications, 12(1), 1764-1764. doi:10.1038/s41467-021-21988-6
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  China is a key region for understanding fire activity and the drivers of its variability under strict fire suppression policies. Here, we present a detailed fire occurrence dataset for China, the Wildfire Atlas of China (WFAC; 2005–2018), based on continuous monitoring from multiple satellites and calibrated against field observations. We find that wildfires across China mostly occur in the winter season from January to April and those fire occurrences generally show a decreasing trend after reaching a peak in 2007. Most wildfires (84%) occur in subtropical China, with two distinct clusters in its southwestern and southeastern parts. In southeastern China, wildfires are mainly promoted by low precipitation and high diurnal temperature ranges, the combination of which dries out plant tissue and fuel. In southwestern China, wildfires are mainly promoted by warm conditions that enhance evaporation from litter and dormant plant tissues. We further find a fire occurrence dipole between southwestern and southeastern China that is modulated by the El Nino-Southern Oscillation (ENSO). Fire activity in China and its associations with climate are not well quantified at a local scale. Here, the authors present a detailed fire occurrence dataset for China and find a dipole fire pattern between southwestern and southeastern China that is modulated by the El Nino-Southern Oscillation (ENSO).
• Heilman, K. A., Trouet, V., Belmecheri, S., Pederson, N., Berke, M. A., & Mclachlan, J. S. (2021). Increased water use efficiency leads to decreased precipitation sensitivity of tree growth, but is offset by high temperatures. Oecologia, 1-16. doi:10.1007/s00442-021-04892-0
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  Both increases in temperature and changes in precipitation may limit future tree growth, but rising atmospheric CO2 could offset some of these stressors through increased plant Water Use Efficiency (WUE). The net balance between the negative impacts of climate change and positive effects of CO2 on tree growth is crucial for ecotones, where increased climate stress could drive mortality and shifts in range. Here, we quantify the effects of climate, stand structure, and rising CO2 on both annual tree-ring growth increment and intrinsic WUE (iWUE) at a savanna-forest boundary in the Upper Midwest United States. Taking a Bayesian hierarchical modelling approach, we find that plant iWUE increased by ~ 16–23% over the course of the twentieth century, but on average, tree-ring growth increments do not significantly increase. Consistent with higher iWUE under increased CO2 and recent wetting, we observe a decrease in sensitivity of tree growth to annual precipitation, leading to ~ 35–41% higher growth under dry conditions compared to trees of similar size in the past. However, an emerging interaction between summer maximum temperatures and annual precipitation diminishes the water-savings benefit under hot and dry conditions. This decrease in precipitation sensitivity, and the interaction between temperature and precipitation are strongest in open canopy microclimates, suggesting that stand structure may modulate response to future changes. Overall, while higher iWUE may provide some water savings benefits to growth under normal drought conditions, near-term future temperature increases combined with drought events could drive growth declines of about 50%.
• Maxwell, J., Bregy, J., Robeson, S., Knapp, P., Soule, P., & Trouet, V. M. (2021). Recent increases in tropical cyclone precipitation extremes over the US East Coast.. Proceedings of the National Academy of Sciences. doi:doi.org/10.1073/pnas.2105636118
• Shanan, I., Kose, N., Akkemik, U., Tuncay, G., Tavsanoglu, C., Bahar, A., Trouet, V. M., & Nuzhet, D. (2021). Fire history of Pinus nigra in Western Anatolia: a first dendro-chronological study. Dendrochronologia. doi:doi.org/10.1016/j.dendro.2021.125874
• Yang, B., Qin, C., Brauning, A., Osborn, T. J., Trouet, V., Yan, M., Wang, X., Wang, S., Wang, J., Stenseth, N. C., Schneider, L., Rossi, S., Ning, L., Luterbacher, J., Ljungqvist, F. C., Griessinger, J., Esper, J., Dong, G., Cook, E. R., & Buntgen, U. (2021). Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years.. Proceedings of the National Academy of Sciences of the United States of America, 118(30). doi:10.1073/pnas.2102007118
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  Asian summer monsoon (ASM) variability and its long-term ecological and societal impacts extending back to Neolithic times are poorly understood due to a lack of high-resolution climate proxy data. Here, we present a precisely dated and well-calibrated tree-ring stable isotope chronology from the Tibetan Plateau with 1- to 5-y resolution that reflects high- to low-frequency ASM variability from 4680 BCE to 2011 CE. Superimposed on a persistent drying trend since the mid-Holocene, a rapid decrease in moisture availability between ∼2000 and ∼1500 BCE caused a dry hydroclimatic regime from ∼1675 to ∼1185 BCE, with mean precipitation estimated at 42 ± 4% and 5 ± 2% lower than during the mid-Holocene and the instrumental period, respectively. This second-millennium-BCE megadrought marks the mid-to late Holocene transition, during which regional forests declined and enhanced aeolian activity affected northern Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE contributed to the shift of Neolithic cultures in northern China and likely triggered human migration and societal transformation.
• Yau, A. W., White, A. E., Whalen, C. B., Wang, K., Trouet, V., Thornton, J. A., Sun, D., Su, H., Sprintall, J., Ritsema, J., Rajaram, H., Qiu, B., Prieto, G. A., Patricola, C. M., Opher, M., Morlighem, M., Magnusdottir, G., Lu, G., Korte, M., , Jacobsen, S. D., et al. (2021). Thank You to Our 2020 Peer Reviewers. Geophysical Research Letters, 48(9). doi:10.1029/2021gl093126
• Alexander, R. M., Rollinson, C., Dye, A., Moore, D. J., Pederson, N., & Trouet, V. M. (2020). Climate sensitivity of understory trees differs from overstory trees in temperate mesic forests.. Ecology. doi:https://doi.org/10.1002/ecy.3264
• Altman, J., Treydte, K., Pejcha, V., Trouet, V. M., & Dolezal, J. (2020). Tree growth response to recent warming of two endemic species in Northeast Asia.. Climatic Change. doi:doi.org/10.1007/s10584-020-02718-1
• Carriquiry-Beltrán, J. D., Trouet, V. M., Leavitt, S. W., & Gutiérrez-García, G. (2020). Tree ring-based historic hydroclimatic variability of the Baja California Peninsula. Journal of Geophysical Research Atmospheres, 125, e2020JD032675. doi:10.1029/2020JD032675.
• De Mil, T., Meko, M., Belmecheri, S., February, E., Therrell, M., Van den Bulcke, J., & Trouet, V. M. (2020). A lonely dot on the map: exploring the climate signal in tree-ring density and stable isotopes of Clanwilliam cedar, South Africa. Dendrochronologia. doi:doi.org/10.1016/j.dendro.2021.125879
• Liu, Y., co-authors, t., Trouet, V. M., Leavitt, S. W., & co-authors, s. (2020). Recent anthropogenic curtailing of Yellow River runoff and sediment load is unprecedented over the past 500 years.. Proceedings of the National Academy of Sciences. doi:https://doi.org/10.1073/pnas.1922349117
• Sprintall, J., Yau, A. W., White, A. E., Wang, K., Trouet, V., Thornton, J. A., Su, H., Sprintall, J., Ritsema, J., Rajaram, H., Patricola, C. M., Opher, M., Morlighem, M., Magnusdottir, G., Lu, G., Korte, M., Jacobsen, S. D., Ivanov, V. Y., Huber, C., , Hogg, A. M., et al. (2020). Thank You to Our 2019 Peer Reviewers. Geophysical Research Letters, 47(17). doi:10.1029/2020gl088048
• Thapa, U., St George, S., & Trouet, V. M. (2020). Poleward Excursions by the Himalayan Subtropical Jet Over the Past Four Centuries. Geophysical Research Letters. doi:https://doi.org/10.1029/2020GL089631
• Xu, G., Wu, G., Liu, X., Hudson, A., & Trouet, V. M. (2020). Age-related climate response of tree-ring d13C and d18O from spruce in northwestern China, with implications for relative humidity reconstructions.. Journal of Geophysical Research - Biogeosciences. doi:https://doi.org/10.1029/2019JG005513
• Xu, G., co-authors, f., Szejner, p., & Trouet, V. M. (2020). Seasonal divergence between soil water availability and atmospheric moisture recorded in intra-annual tree-ring δ18O extremes. Environmental Research Letters. doi:https://doi.org/10.1088/1748-9326/ab9792
• Zafirov, N., Panayotov, M., Tsvetanov, N., Nikolchova, I., & Trouet, V. M. (2020). Dendroclimatic analysis of Pinus peuce Griseb. At subalpine and treeline locations in Pirin Mountains, Bulgaria. Dendrochronologia. doi:https://doi.org/10.1016/j.dendro.2020.125703
• Babst, F., Bouriaud, O., Poulter, B., Trouet, V., Girardin, M. P., & Frank, D. C. (2019). Twentieth century redistribution in climatic drivers of global tree growth. SCIENCE ADVANCES, 5(1).
• Bjoerklund, J., De Mil, T., Meko, M., Trouet, V. M., & Frank, D. C. (2019). Scientific Merits and Analytical Challenges of Tree‐Ring Densitometry. Reviews of Geophysics. doi:https://doi.org/10.1029/2019RG000642
• Hudson, A. R., Alfaro-Sanchez, R., Babst, F., Belmecheri, S., Moore, D., & Trouet, V. (2019). Seasonal and synoptic climatic drivers of tree growth in the Bighorn Mountains, WY, USA (1654-1983 CE). DENDROCHRONOLOGIA, 58.
• Klippel, L., Krusic, P. J., Konter, O., St, G. S., Trouet, V., & Esper, J. (2019). A 1200+year reconstruction of temperature extremes for the northeastern Mediterranean region. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 39(4), 2336-2350.
• Wahl, E., Zorita, E., Trouet, V. M., & Taylor, A. (2019). Jet stream dynamics, hydroclimate, and fire in California from 1600 CE to present. Proceedings of the National Academy of Sciences.
• Xu, G., Liu, X., Zhang, Q., Hudson, A., & Trouet, V. M. (2019). Century-scale temperature variability and onset of industrial-era warming in the Eastern Tibetan Plateau. Climate Dynamics. doi:https://doi.org/10.1007/s00382-019-04807-z
• Alfaro-Sanchez, R., Camarero, J., Sanchez-Salguero, R., Trouet, V. M., & De Las Heras, J. (2018). How do droughts and wildfires alter seasonal radial growth in Mediterranean Aleppo pine forests?. Tree-Ring Research.
• Alfaro-Sanchez, R., Nguyen, H., Klesse, S., Hudson, A., Belmecheri, S., Kose, N., Diaz, H. F., Monson, R. K., Villalba, R., & Trouet, V. (2018). Climatic and volcanic forcing of tropical belt northern boundary over the past 800 years. NATURE GEOSCIENCE, 11(12), 933-+.
• Babst, F., Bodesheim, P., Charney, N., Friend, A. D., Girardin, M. P., Klesse, S., Moore, D., Seftigen, K., Bjorklund, J., Bouriaud, O., Dawson, A., DeRose, R. J., Dietze, M. C., Eckes, A. H., Enquist, B., Frank, D. C., Mahecha, M. D., Poulter, B., Record, S., , Trouet, V., et al. (2018). When tree rings go global: Challenges and opportunities for retro- and prospective insight. QUATERNARY SCIENCE REVIEWS, 197, 1-20.
• Babst, F., Trouet, V., Rollinson, C. R., Moore, D. J., Babst, F., & Alexander, M. R. (2018). Relative influences of multiple sources of uncertainty on cumulative and incremental tree-ring-derived aboveground biomass estimates. Trees-structure and Function, 32(1), 265-276. doi:10.1007/s00468-017-1629-0
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  How forest growth responds to climate change will impact the global carbon cycle. The sensitivity of tree growth and thus forest productivity to climate can be inferred from tree-ring increments, but individual tree responses may differ from the overall forest response. Tree-ring data have also been used to estimate interannual variability in aboveground biomass, but a shortage of robust uncertainty estimates often limits comparisons with other measurements of the carbon cycle across variable ecological settings. Here we identify and quantify four important sources of uncertainty that affect tree-ring-based aboveground biomass estimates: subsampling, allometry, forest density (sampling), and mortality. In addition, we investigate whether transforming rings widths into biomass affects the underlying growth-climate relationships at two coniferous forests located in the Valles Caldera in northern New Mexico. Allometric and mortality sources of uncertainty contributed most (34–57 and 24–42%, respectively) and subsampling uncertainty least (7–8%) to the total uncertainty for cumulative biomass estimates. Subsampling uncertainty, however, was the largest source of uncertainty for year-to-year variations in biomass estimates, and its large contribution indicates that between-tree growth variability remains influential to changes in year-to-year biomass estimates for a stand. The effect of the large contribution of the subsampling uncertainty is reflected by the different climate responses of large and small trees. Yet, the average influence of climate on tree growth persisted through the biomass transformation, and the biomass growth-climate relationship is comparable to that found in traditional climate reconstruction-oriented tree-ring chronologies. Including the uncertainties in estimates of aboveground biomass will aid comparisons of biomass increment across disparate forests, as well as further the use of these data in vegetation modeling frameworks.
• Ols, C., Trouet, V., Girardin, M. P., Hofgaard, A., Bergeron, Y., & Drobyshev, I. (2018). Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate. GLOBAL AND PLANETARY CHANGE, 165, 1-12.
• Trouet, V. M., Babst, F., & Meko, M. (2018). Recent enhanced high-summer North Atlantic Jet variability emerges from three-century context. Nature Communications. doi:doi.org/10.1038/s41467-017-02699-3
• Xu, G., Liu, X., Trouet, V. M., Treydte, K., Wen, G., Chen, T., Sun, W., Wang, W., Zeng, X., & Qin, D. (2018). Regional drought shifts (1700-2011) in East Central Asia and linkages with atmospheric circulation recorded in tree-ring d18O.. Climate Dynamics. doi:doi.org/10.1007/s00382-018-4215-2
• Alexander, R., Rollinson, C., Babst, F., Trouet, V. M., & Moore, D. J. (2017). Uncertainty in tree-ring based biomass estimates does not alter growth-climate relationships.. Trees - Structure and Function.
• Belmecheri, S., Babst, F., Hudson, A. R., Betancourt, J., & Trouet, V. (2017). Northern Hemisphere Jet Stream Position Indices as Diagnostic Tools for Climate and Ecosystem Dynamics. EARTH INTERACTIONS, 21, 1-23.
• Klippel, L., Krusic, P. J., Brandes, R., Hartl-Meier, C., Trouet, V., Meko, M., & Esper, J. (2017). High-elevation inter-site differences in Mount Smolikas tree-ring width data. DENDROCHRONOLOGIA, 44, 164-173.
• Konter, O., Krusic, P., Trouet, V. M., & Esper, J. (2017). Meet Adonis, Europe’s oldest dendrochronologically dated tree.. Dendrochronologia.
• Marlon, J. R., Pederson, N., Nolan, C., Goring, S., Shuman, B., Robertson, A., Booth, R., Bartlein, P. J., Berke, M. A., Clifford, M., Cook, E., Dieffenbacher-Krall, A., Dietze, M. C., Hessl, A., Hubeny, J. B., Jackson, S. T., Marsicek, J., McLachlan, J., Mock, C. J., , Moore, D., et al. (2017). Climatic history of the northeastern United States during the past 3000 years. CLIMATE OF THE PAST, 13(10), 1355-1379.
• Montane, F., Fox, A. M., Arellano, A. F., MacBean, N., Alexander, M. R., Dye, A., Bishop, D. A., Trouet, V., Babst, F., Hessl, A. E., Pederson, N., Blanken, P. D., Bohrer, G., Gough, C. M., Litvak, M. E., Novick, K. A., Phillips, R. P., Wood, J. D., & Moore, D. (2017). Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5) on carbon fluxes, pools, and turnover in temperate forests. GEOSCIENTIFIC MODEL DEVELOPMENT, 10(9), 3499-3517.
• Yao, Q., Brown, P., Liu, S., Rocca, M., Trouet, V. M., Zheng, B., Chen, H., Li, Y., & Wang, X. (2017). Pacific-Atlantic Ocean influence on wildfires in northeast China (1774 to 2010). Geophysical Research Letters.
• Belmecheri, S., Babst, F., Wahl, E. R., Stahle, D. W., & Trouet, V. (2016). Multi-century evaluation of Sierra Nevada snowpack. NATURE CLIMATE CHANGE.
• Black, B., Griffin, D., Van der Sleen, P., Wanamaker, A., Speer, J., Frank, D., Stahle, D., Pederson, N., Copenheaver, C., Trouet, V. M., Griffin, S., & Gillander, B. (2016). The value of crossdating to retain high-frequency variability, climate signals, and extreme events in environmental proxies.. Global Change Biology. doi:10.1111/gcb.13256
• Charney, N., Babst, F., Poulter, B., Record, S., Trouet, V. M., Frank, D. C., Enquist, B. J., & Evans, M. E. (2016). Observed forest sensitivity to climate implies larger reductions in 21st century forest growth. Ecology Letters.
• Esper, J., Krusic, P. J., Ljungqvist, F. J., Luterbacher, J., Carrer, M., Cook, E. R., Davi, N., Hartl-Meier, C., Kirdyanov, A., Konter, O., Myglan, V., Timonen, M., Treydte, K., Trouet, V. M., Villalba, R., & Yang, B. (2016). Ranking of tree-ring based temperature reconstructions of the past millennium. Quaternary Science Reviews.
• O'Donnell, A., Allen, K., Evans, R., Cook, E. R., Trouet, V. M., & Baker, P. (2016). Wood density provides new opportunities for reconstructing past temperature variability from southeastern Australian trees.. Global and Planetary Change.
• Szejner, P., Wright, W., Babst, F., Belmecheri, S., Trouet, V. M., Leavitt, S. W., Ehleringer, J., & Monson, R. K. (2016). Latitudinal gradients in tree-ring stable carbon and oxygen isotopes reveal differential climate influences of the North American Monsoon system.. Journal of Geophysical Research - Biogeosciences, 121(7), 1978-1991. doi:10.1002/2016JG003460
• Taylor, A. H., Trouet, V. M., Skinner, C., & Stephens, S. (2016). Socio-Ecological transitions trigger fire regime shifts and modulate fire-climate interactions in the Sierra Nevada, USA 1600-2015 CE. Proceedings of the National Academy of Sciences.
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  Taylor and Trouet are co-lead authors
• Trouet, V., Harley, G. L., & Dominguez-delmas, M. (2016). Shipwreck rates reveal Caribbean tropical cyclone response to past radiative forcing.. Proceedings of the National Academy of Sciences of the United States of America, 113(12), 3169-74. doi:10.1073/pnas.1519566113
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  Assessing the impact of future climate change on North Atlantic tropical cyclone (TC) activity is of crucial societal importance, but the limited quantity and quality of observational records interferes with the skill of future TC projections. In particular, North Atlantic TC response to radiative forcing is poorly understood and creates the dominant source of uncertainty for twenty-first-century projections. Here, we study TC variability in the Caribbean during the Maunder Minimum (MM; 1645-1715 CE), a period defined by the most severe reduction in solar irradiance in documented history (1610-present). For this purpose, we combine a documentary time series of Spanish shipwrecks in the Caribbean (1495-1825 CE) with a tree-growth suppression chronology from the Florida Keys (1707-2009 CE). We find a 75% reduction in decadal-scale Caribbean TC activity during the MM, which suggests modulation of the influence of reduced solar irradiance by the cumulative effect of cool North Atlantic sea surface temperatures, El Niño-like conditions, and a negative phase of the North Atlantic Oscillation. Our results emphasize the need to enhance our understanding of the response of these oceanic and atmospheric circulation patterns to radiative forcing and climate change to improve the skill of future TC projections.
• Yu, Z., Williams, J. W., Umbanhowar, C. E., Trouet, V., Shuman, B. N., Schaefer, K., Robertson, A., Peteet, D. M., Pederson, N., Nolan, C., Nichols, J., Moore, D. J., Mock, C. J., Mclachlan, J. S., Marsicek, J., Marlon, J. R., Jackson, S. T., Hubeny, J. B., Hessl, A. E., , Goring, S., et al. (2016). Climatic history of the northeastern United States during the past 3000 years. Climate of The Past, 13(10), 1355-1379. doi:10.5194/cp-13-1355-2017
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  Abstract. Many ecosystem processes that influence Earth system feedbacks – vegetation growth, water and nutrient cycling, disturbance regimes – are strongly influenced by multidecadal- to millennial-scale climate variations that cannot be directly observed. Paleoclimate records provide information about these variations, forming the basis of our understanding and modeling of them. Fossil pollen records are abundant in the NE US, but cannot simultaneously provide information about paleoclimate and past vegetation in a modeling context because this leads to circular logic. If pollen data are used to constrain past vegetation changes, then the remaining paleoclimate archives in the northeastern US (NE US) are quite limited. Nonetheless, a growing number of diverse reconstructions have been developed but have not yet been examined together. Here we conduct a systematic review, assessment, and comparison of paleotemperature and paleohydrological proxies from the NE US for the last 3000 years. Regional temperature reconstructions (primarily summer) show a long-term cooling trend (1000 BCE–1700 CE) consistent with hemispheric-scale reconstructions, while hydroclimate data show gradually wetter conditions through the present day. Multiple proxies suggest that a prolonged, widespread drought occurred between 550 and 750 CE. Dry conditions are also evident during the Medieval Climate Anomaly, which was warmer and drier than the Little Ice Age and drier than today. There is some evidence for an acceleration of the longer-term wetting trend in the NE US during the past century; coupled with an abrupt shift from decreasing to increasing temperatures in the past century, these changes could have wide-ranging implications for species distributions, ecosystem dynamics, and extreme weather events. More work is needed to gather paleoclimate data in the NE US to make inter-proxy comparisons and to improve estimates of uncertainty in reconstructions.
• Anchukaitis, K. J., Lorrey, A. M., Prieto, M., White, J., Ommen, T. V., Graham, R., Zorita, E., Yasue, K., White, J. W., Werner, J. P., Wanner, H., Wahl, E. R., Wagner, S., Vinther, B. M., Villalba, R., Viau, A. E., Verschuren, D., Umer, M., Turney, C. S., , Trouet, V., et al. (2015). Corrigendum: Continental-scale temperature variability during the past two millennia. Nature Geoscience, 8(12), 981-982. doi:10.1038/ngeo2566
• Baker, A., Hellstrom, J. C., Kelly, B. F., Mariethoz, G., & Trouet, V. (2015). A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia. SCIENTIFIC REPORTS, 5.
• Baker, A., Hellstrom, J., Kelly, B. F., Mariethoz, G., & Trouet, V. M. (2015). A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia.. Nature Scientific Reports.
• Dawson, A., Austin, D., Walker, D., Appleton, S., Gillanders, B. M., Griffin, S. M., Sakata, C., & Trouet, V. (2015). A tree-ring based reconstruction of early summer precipitation in southwestern Virginia (1750-1981). CLIMATE RESEARCH, 64(3), 243-256.
• Frank, D., Touchan, R., Wazny, T., Zang, C., Wilson, R., Wazny, T., Walder, F., Trouet, V., Trotsiuk, V., Touchan, R., Timonen, M., Thun, T., Tegel, W., Svoboda, M., Svarva, H. L., Seim, A., Seftigen, K., Seager, R., Schrier, G. V., , Rothe, A., et al. (2015). Old World megadroughts and pluvials during the Common Era.. Science advances, 1(10), e1500561. doi:10.1126/sciadv.1500561
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  Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other "Old World" climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the "Old World Drought Atlas" (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability.
• Klesse, S., Ziehmer, M., Rousakis, G., Trouet, V., & Frank, D. (2015). Synoptic drivers of 400 years of summer temperature and precipitation variability on Mt. Olympus, Greece. CLIMATE DYNAMICS, 45(3-4), 807-824.
• Seim, A., Treydte, K., Trouet, V., Frank, D., Fonti, P., Tegel, W., Panayotov, M., Fernandez-Donado, L., Krusic, P., & Buentgen, U. (2015). Climate sensitivity of Mediterranean pine growth reveals distinct east-west dipole. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 35(9), 2503-2513.
• Trouet, V. (2015). Peer review report 1 On ``Fire weather and large fire potential in the northern Sierra Nevada''. Agricultural and Forest Meteorology, 201, 338. doi:10.1016/j.agrformet.2015.08.155
• Trouet, V. M., Harley, G. H., & Dominguez-Delmas, M. (2015). North Atlantic tropical cyclone response to radiative forcing revealed by shipwrecks. Proceedings of the National Academy of Sciences.
• Babst, F., Alexander, M. R., Szejner, P., Bouriaud, O., Klesse, S., Roden, J., Ciais, P., Poulter, B., Frank, D., Moore, D. J., & Trouet, V. (2014). A tree-ring perspective on the terrestrial carbon cycle. Oecologia, 176(2), 307-22.
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  Tree-ring records can provide valuable information to advance our understanding of contemporary terrestrial carbon cycling and to reconstruct key metrics in the decades preceding monitoring data. The growing use of tree rings in carbon-cycle research is being facilitated by increasing recognition of reciprocal benefits among research communities. Yet, basic questions persist regarding what tree rings represent at the ecosystem level, how to optimally integrate them with other data streams, and what related challenges need to be overcome. It is also apparent that considerable unexplored potential exists for tree rings to refine assessments of terrestrial carbon cycling across a range of temporal and spatial domains. Here, we summarize recent advances and highlight promising paths of investigation with respect to (1) growth phenology, (2) forest productivity trends and variability, (3) CO2 fertilization and water-use efficiency, (4) forest disturbances, and (5) comparisons between observational and computational forest productivity estimates. We encourage the integration of tree-ring data: with eddy-covariance measurements to investigate carbon allocation patterns and water-use efficiency; with remotely sensed observations to distinguish the timing of cambial growth and leaf phenology; and with forest inventories to develop continuous, annually-resolved and long-term carbon budgets. In addition, we note the potential of tree-ring records and derivatives thereof to help evaluate the performance of earth system models regarding the simulated magnitude and dynamics of forest carbon uptake, and inform these models about growth responses to (non-)climatic drivers. Such efforts are expected to improve our understanding of forest carbon cycling and place current developments into a long-term perspective.
• Babst, F., Bouriaud, O., Alexander, R., Trouet, V., & Frank, D. (2014). Toward consistent measurements of carbon accumulation: A multi-site assessment of biomass and basal area increment across Europe. Dendrochronologia.
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  Abstract: The use of tree-ring data in carbon cycle research has so far been limited because traditional study designs are not geared toward quantifying forest carbon accumulation. Existing studies that assessed biomass increment from tree rings were often confined to individual sites and used inconsistent sampling schemes. We applied a consistent biomass-oriented sampling design at five managed forest sites located in different climate zones to assess the annual carbon accumulation in above-ground woody tissues (i.e. stems and branches) and its climate response. Radial growth and biometric measurements were combined to reconstruct the annual biomass increment in individual trees and upscaled to the site level. In addition to this, we estimated that 32-60 trees are required at these five sites to robustly quantify carbon accumulation rates. Tree dimensions and growth rates varied considerably among sites as a function of differing stand density, climatic limitations, and management interventions. Accordingly, mean site-level carbon accumulation rates between 65 g C m-2 y-1 and 225 g C m-2 y-1 were reconstructed for the 1970-2009 period. A comparison of biomass increment with the widely used basal area increment (BAI) revealed very similar growth trends but emphasized the merits of biomass assessments due to species-specific BAI/biomass relationship. Our study illustrates the benefits and challenges of combining tree-ring data with biometric measurements and promotes the consistent application of a standardized sampling protocol across large spatial scales. It is thus viewed as a conceptual basis for future use of tree-ring data to approach research questions related to forest productivity and the terrestrial carbon balance. © 2014 Elsevier GmbH. All rights reserved.
• Trouet, V. M. (2014). A tree-ring based late summer temperature reconstruction (1675-1980) for the northeastern Mediterranean. Tree-Ring Research/Radiocarbon, 56(4), 69-78.
• Trouet, V. M., Diaz, H., & Trouet, V. (2014). Some Perspectives on Societal Impacts of Past Climatic Changes. History Compass, 1-18.
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  DOI:10.1111/hic3.12140
• Ahmed, M., Anchukaitis, K. J., Asrat, A., Borgaonkar, H. P., Braida, M., Buckley, B. M., Büntgen, U., Chase, B. M., Christie, D. A., Cook, E. R., A., M., Diaz, H. F., Esper, J., Fan, Z., Gaire, N. P., Quansheng, G. e., Gergis, J., González-Rouco, J. F., Goosse, H., , Grab, S. W., et al. (2013). Continental-scale temperature variability during the past two millennia. Nature Geoscience, 6(5), 339-346.
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  Abstract: Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971-2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
• Babst, F., Poulter, B., Trouet, V., Tan, K., Neuwirth, B., Wilson, R., Carrer, M., Grabner, M., Tegel, W., Levanic, T., Panayotov, M., Urbinati, C., Bouriaud, O., Ciais, P., & Frank, D. (2013). Site- and species-specific responses of forest growth to climate across the European continent. Global Ecology and Biogeography, 22(6), 706-717.
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  Abstract: Aim: To evaluate the climate sensitivity of model-based forest productivity estimates using a continental-scale tree-ring network. Location: Europe and North Africa (30-70°N, 10°W-40°E). Methods: We compiled close to 1000 annually resolved records of radial tree growth for all major European tree species and quantified changes in growth as a function of historical climatic variation. Sites were grouped using a neural network clustering technique to isolate spatiotemporal and species-specific climate response patterns. The resulting empirical climate sensitivities were compared with the sensitivities of net primary production (NPP) estimates derived from the ORCHIDEE-FM and LPJ-wsl dynamic global vegetation models (DGVMs). Results: We found coherent biogeographic patterns in climate response that depend upon (1) phylogenetic controls and (2) ambient environmental conditions delineated by latitudinal/elevational location. Temperature controls dominate forest productivity in high-elevation and high-latitude areas whereas moisture sensitive sites are widespread at low elevation in central and southern Europe. DGVM simulations broadly reproduce the empirical patterns, but show less temperature sensitivity in the boreal zone and stronger precipitation sensitivity towards the mid-latitudes. Main conclusions: Large-scale forest productivity is driven by monthly to seasonal climate controls, but our results emphasize species-specific growth patterns under comparable environmental conditions. Furthermore, we demonstrate that carry-over effects from the previous growing season can significantly influence tree growth, particularly in areas with harsh climatic conditions - an element not considered in most current-state DGVMs. Model-data discrepancies suggest that the simulated climate sensitivity of NPP will need refinement before carbon-cycle climate feedbacks can be accurately quantified. © 2012 John Wiley & Sons Ltd.
• Ridder, M. d., Trouet, V., van, J., Hubau, W., Acker, J. v., & Beeckman, H. (2013). A tree-ring based comparison of Terminalia superba climate-growth relationships in West and Central Africa. Trees - Structure and Function, 27(5), 1225-1238.
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  Abstract: Tropical lowland forests are characterized by humid climate conditions with interannual variations in amount of precipitation, length of dry season, and relative humidity. The African tree species, Terminalia superba Engl. & Diels has a large distribution area and potentially incorporates these variations in its tree rings. Tree ring analysis was performed on 60 plantation trees (increment cores) and 41 natural trees (stem disks) from Ivory Coast and the Congolese Mayombe Forest. Natural forests and old plantations (50-55 years) showed similar growth patterns. Regional chronologies were developed for the two sample regions and showed a long-distance relationship for the period 1959-2008. Growth in the Mayombe was associated with early rainy season precipitation, but no relation was found between tree growth and precipitation in Ivory Coast. Congolese trees possibly show a higher climate-sensitivity than Ivorian trees, because precipitation in the Mayombe is more limiting, and Congolese T. superba trees are found closer to the margins of their distribution. Likewise, tree growth in the Mayombe was also influenced by the SSTs of the Gulf of Guinea and the South Atlantic Ocean during the early rainy season. However, tree growth was influenced by ENSO in both regions. In the Mayombe, La Niña years were associated with stronger tree growth whereas in Ivory Coast, El Niño years corresponded with stronger tree growth. The presented relation between ENSO, precipitation and tree growth is original for equatorial African forests, suggesting an influence of global climate variability on tree growth. © 2013 Springer-Verlag Berlin Heidelberg.
• Trouet, V., & Jan, G. (2013). KNMI climate explorer: A web-based research tool for high-resolution paleoclimatology. Tree-Ring Research, 69(1), 3-13.
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  Abstract: Climate Explorer (www.climexp.knmi.nl) is a web-based application for climatic research that is managed by the Royal Netherlands Meteorological Institute (KNMI) and contains a comprehensive collection of climatic data sets and analysis tools. One of its fields of application is high-resolution paleoclimatology. We show how Climate Explorer can be used to explore and download available instrumental climate data and derived time series, to examine the climatic signal in uploaded high-resolution paleoclimate time series, and to investigate the temporal and spatial characteristics of climate reconstructions. We further demonstrate the value of Climate Explorer for high-resolution paleoclimate research using a dendroclimatic data set from the High Atlas Mountains in Morocco. © 2013 The Tree-Ring Society.
• Trouet, V., Diaz, H. F., Wahl, E. R., Viau, A. E., Graham, R., Graham, N., & Cook, E. R. (2013). A 1500-year reconstruction of annual mean temperature for temperate North America on decadal-to-multidecadal time scales. Environmental Research Letters, 8(2).
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  Abstract: We present two reconstructions of annual average temperature over temperate North America: a tree-ring based reconstruction at decadal resolution (1200-1980 CE) and a pollen-based reconstruction at 30 year resolution that extends back to 480 CE. We maximized reconstruction length by using long but low-resolution pollen records and applied a three-tier calibration scheme for this purpose. The tree-ring-based reconstruction was calibrated against instrumental annual average temperatures on annual and decadal scale, it was then reduced to a lower resolution, and was used as a calibration target for the pollen-based reconstruction. Before the late-19th to the early-21st century, there are three prominent low-frequency periods in our extended reconstruction starting at 480 CE, notably the Dark Ages cool period (about 500-700 CE) and Little Ice Age (about 1200-1900 CE), and the warmer medieval climate anomaly (MCA; about 750-1100 CE). The 9th and the 11th century are the warmest centuries and they constitute the core of the MCA in our reconstruction, a period characterized by centennial-scale aridity in the North American West. These two warm peaks are slightly warmer than the baseline period (1904-1980), but nevertheless much cooler than temperate North American temperatures during the early-21st century. © 2013 IOP Publishing Ltd.
• Diaz, H. F., Trouet, V., Stahle, D. W., & Diaz, H. F. (2012). North American Dendroclimatic Data: Compilation, Characterization, and Spatiotemporal Analysis. PAGES News, 20(1), 52-52. doi:10.22498/pages.20.1.52
• Seim, A., Büntgen, U., Fonti, P., Haska, H., Herzig, F., Tegel, W., Trouet, V., & Treydte, K. (2012). Climate sensitivity of a millennium-long pine chronology from Albania. Climate Research, 51(3), 217-228.
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  Abstract: Considerable progress has been made in assessing European climate variations of the last millennium, but little is known about the Mediterranean region and particularly its eastern part including the Balkan Peninsula. This area, however, will be particularly vulnerable to a predicted temperature increase and precipitation decrease, likely resulting in amplified drought extremes and episodes. Here we present a well-replicated composite tree-ring width chronology of millennial length from Albania, Balkan Peninsula. The Pinus heldreichii Christ dataset contains 302 series from 217 living and dead trees from 3 high-elevation sites, and spans the years 968-2008. Signal strength and growth-climate relationships were investigated using subsets according to location, age class, and growth level, as well as differently detrended chronology versions. Growth comparisons amongst the 3 sites' chronologies, between age classes and between growth-rate groups reveal an overall strong common signal. Growth-climate relationships over the last 100 yr, however, indicate that tree-ring formation does not depend on one single dominant factor, but rather on various combinations of summer precipitation and temperature resulting in temporally varying drought sensitivity. Our results emphasize a mixed and variable climate signal, corresponding with findings from other P. heldreichii sites across the Balkan Peninsula and Southern Italy. © Inter-Research 2012.
• Trouet, V., Diaz, H., Viau, A., & Wahl, E. (2012). A pollen-based extension of the 800-year decadal-scale reconstruction of annual mean temperature for temperate North America dating back to 480 AD. PAGES News, 20(2), 87-88.
• Trouet, V., Mukelabai, M., Verheyden, A., & Beeckman, H. (2012). Cambial Growth Season of Brevi-Deciduous Brachystegia spiciformis Trees from South Central Africa Restricted to Less than Four Months. PLoS ONE, 7(10).
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  PMID: 23071794;PMCID: PMC3468463;Abstract: We investigate cambial growth periodicity in Brachystegia spiciformis, a dominant tree species in the seasonally dry miombo woodland of southern Africa. To better understand how the brevi-deciduous (experiencing a short, drought-induced leaf fall period) leaf phenology of this species can be linked to a distinct period of cambial activity, we applied a bi-weekly pinning to six trees in western Zambia over the course of one year. Our results show that the onset and end of cambial growth was synchronous between trees, but was not concurrent with the onset and end of the rainy season. The relatively short (three to four months maximum) cambial growth season corresponded to the core of the rainy season, when 75% of the annual precipitation fell, and to the period when the trees were at full photosynthetic capacity. Tree-ring studies of this species have found a significant relationship between annual tree growth and precipitation, but we did not observe such a correlation at intra-annual resolution in this study. Furthermore, a substantial rainfall event occurring after the end of the cambial growth season did not induce xylem initiation or false ring formation. Low sample replication should be taken into account when interpreting the results of this study, but our findings can be used to refine the carbon allocation component of process-based terrestrial ecosystem models and can thus contribute to a more detailed estimation of the role of the miombo woodland in the terrestrial carbon cycle. Furthermore, we provide a physiological foundation for the use of Brachystegia spiciformis tree-ring records in paleoclimate research. © 2012 Trouet et al.
• Trouet, V., Panayotov, M. P., Ivanova, A., & Frank, D. (2012). A pan-European summer teleconnection mode recorded by a new temperature reconstruction from the northeastern Mediterranean (ad 1768-2008). Holocene, 22(8), 887-898.
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  Abstract: The dominant atmospheric circulation pattern that governs European summer climate is a blocking-like pattern over the British Isles that co-occurs with a low over southeastern Europe. The meridionally oriented configuration of this circulation pattern favours the intrusion of warm air over the northeastern Mediterranean during one mode and over northwestern Europe during its opposite mode. We present a summer temperature reconstruction (1768-2008) for the southeastern node of this teleconnection pattern. This reconstruction is based on maximum latewood density (MXD) measurements of 23 Pinus heldreichii trees from a high-elevation stand in the Pirin Mountains in Bulgaria. The temperature signal in trees from high-elevation, summer-dry regions is stronger in MXD measurements compared with tree-ring width data and our reconstruction reflects well interannual- to decadal-scale summer temperature fluctuations in the Balkans as instrumentally recorded over the twentieth century. Fluctuations in our Bulgarian reconstruction correspond to summer temperature variability in the Balkans, Italy, and the southern Carpathians, but opposing temperature variability patterns are manifested over the British Isles and southern Scandinavia. The strong and consistent anti-phase relationship between our reconstruction and a reconstruction of the summer North Atlantic Oscillation (sNAO) suggests that the sNAO pattern is a main driver of the teleconnection between summer temperatures in southeastern versus northwestern Europe. This teleconnection is most pronounced on interannual timescales and has been stable over the last two centuries. © The Author(s) 2012.
• Trouet, V., Scourse, J. D., & Raible, C. C. (2012). North Atlantic storminess and Atlantic Meridional Overturning Circulation during the last Millennium: Reconciling contradictory proxy records of NAO variability. Global and Planetary Change, 84-85, 48-55.
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  Abstract: Within the last Millennium, the transition between the Medieval Climate Anomaly (MCA; ca. 1000-1300. CE) and the Little Ice Age (LIA; ca. 1400-1800. CE) has been recorded in a global array of climatic and oceanographic proxies. In this study, we review proxy evidence for two alternative hypotheses for the effects of this shift in the North Atlantic region. One hypothesis postulates that the MCA/LIA transition included a weakening of the Atlantic Meridional Overturning Circulation (AMOC) and a transition to more negative North Atlantic Oscillation (NAO) conditions, resulting in a strong cooling of the North Atlantic region. The alternative hypothesis proposes a MCA/LIA shift to an increased number of storms over the North Atlantic linked to increased mid-latitude cyclogenesis and hence a pervasive positive NAO state. The two sets of proxy records and thus of the two competing hypotheses are then reconciled based on available results from climate model simulations of the last Millennium. While an increase in storm frequency implicates positive NAO, increased intensity would be consistent with negative NAO during the LIA. Such an increase in cyclone intensity could have resulted from the steepening of the meridional temperature gradient as the poles cooled more strongly than the Tropics from the MCA into the LIA. © 2011 Elsevier B.V.
• Wahl, E., Diaz, H., Trouet, V., & Cook, E. (2012). An 800-year decadal-scale reconstruction of annual mean temperature for temperate North America. PAGES News, 20(2), 86-87.
• Baker, A., Wilson, R., Fairchild, I. J., Franke, J., Spötl, C., Mattey, D., Trouet, V., & Fuller, L. (2011). High resolution δ¹⁸O and δ¹³C records from an annually laminated Scottish stalagmite and relationship with last millennium climate. Global and Planetary Change, 79(3-4), 303-311.
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  Abstract: High-resolution (annual to decadal) stable isotope records of oxygen and carbon are analysed from an annually laminated stalagmite from NW Scotland. The sample, which was deposited for ~1000yrs until 1996AD, has previously provided annual resolution climate reconstructions of local rainfall and regional winter North Atlantic Oscillation (wNAO) from variations in annual growth rate. For our stalagmite, for which modern cave monitoring demonstrates that equilibrium deposition is highly likely for δ18O but not for δ13C, stalagmite δ13C originally derives from soil CO2 produced predominantly by microbial respiration, modified by degassing-related kinetic fractionation, and δ18O from the composition of infiltrating water during periods of infiltrating water. Both the presence of fluorescent laminae and modern drip-water monitoring demonstrate a drip hydrology that comprises both event and storage components. Over the instrumental period, no correlations between stalagmite or rainfall δ18O and precipitation amount or temperature are observed, but correlations are observed between rainfall δ18O and 500mb height at regional IAEA monitoring stations. However, no correlations are observed between stalagmite δ18O and instrumental and reconstructed atmospheric circulation, preventing a simple palaeoclimate interpretation of the stalagmite δ18O proxy. Stalagmite δ13C has a stronger temporal autocorrelation than δ18O, indicative of soil mixing of respired CO2 and significant variability between drips and at different times; correlations with instrumental climate data are therefore not possible. The relative timing of changes in growth rate, δ18O and δ13C are discussed, and interpretations compared with other regional climate records. We conclude that, over the last millennium at this mid-latitude cave site, neither δ18O nor δ13C cannot be interpreted as a simple paleoclimate proxy. © 2010 Elsevier B.V.
• Büntgen, U., Tegel, W., Nicolussi, K., McCormick, M., Frank, D., Trouet, V., Kaplan, J. O., Herzig, F., Heussner, K., Wanner, H., Luterbacher, J., & Esper, J. (2011). 2500 years of European climate variability and human susceptibility. Science, 331(6017), 578-582.
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  PMID: 21233349;Abstract: Climate variations influenced the agricultural productivity, health risk, and conflict level of preindustrial societies. Discrimination between environmental and anthropogenic impacts on past civilizations, however, remains difficult because of the paucity of high-resolution paleoclimatic evidence. We present tree ring - based reconstructions of central European summer precipitation and temperature variability over the past 2500 years. Recent warming is unprecedented, but modern hydroclimatic variations may have at times been exceeded in magnitude and duration. Wet and warm summers occurred during periods of Roman and medieval prosperity. Increased climate variability from ∼250 to 600 C.E. coincided with the demise of the western Roman Empire and the turmoil of the Migration Period. Such historical data may provide a basis for counteracting the recent political and fiscal reluctance to mitigate projected climate change.
• Büntgen, U., Frank, D., Trouet, V., & Esper, J. (2010). Diverse climate sensitivity of Mediterranean tree-ring width and density. Trees - Structure and Function, 24(2), 261-273.
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  Abstract: Understanding long-term environmental controls on the formation of tree-ring width (TRW) and maximum latewood density (MXD) is fundamental for evaluating parameter-specific growth characteristics and climate reconstruction skills. This is of particular interest for mid-latitudinal environments where future rates of climate change are expected to be most rapid. Here we present a network of 28 TRW and 21 MXD chronologies from living and relict conifers. Data cover an area from the Atlantic Ocean in the west to the Mediterranean Sea in the east and an altitudinal gradient from 1,000 to 2,500 m asl. Age trends, spatial autocorrelation functions, carry-over effects, variance changes, and climate responses were analyzed for the individual sites and two parameter-specific regional means. Variations in warm season (May-September) temperature mainly control MXD formation (r = 0.58 to 0.87 from inter-annual to decadal time-scales), whereas lower TRW sensitivity to temperature remains unstable over space and time. © Springer-Verlag 2009.
• Büntgen, U., Trouet, V., Frank, D., Leuschner, H. H., Friedrichs, D., Luterbacher, J., & Esper, J. (2010). Tree-ring indicators of German summer drought over the last millennium. Quaternary Science Reviews, 29(7-8), 1005-1016.
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  Abstract: Past natural and future anthropogenic drought variability has and will impact terrestrial ecosystems, agricultural productivity, socio-economic conditions, and public health on various time-scales. In comparison to reconstructed and projected temperature change, much less is known about variations in the hydrological cycle. Here we present 953 living and historical oak (Quercus sp) ring width samples from Central Germany (51-52°N and 9-10°E), that span the AD 996-2005 period and explain ∼18-70% of inter-annual to decadal scale June-September drought variance at the regional-scale. Driest and wettest summers common to the tree-ring proxy and instrumental target data are 1934, 1959, 1996 and 1958, 1966, 1967, respectively. Spatial field correlations are positive with gridded summer hydro-climate over western-central Europe. Increased mid-tropospheric geopotential height (Z500) anomalies over the British Isles appear associated with increased Central German drought, whereas negative Z500 anomalies over Western Europe trigger wet summer extremes due to anomalous moist air advection from the west. Although our study revealed estimates of inter-annual to decadal drought dynamics at the synoptic scale, lower frequency trends remain insecure. © 2010 Elsevier Ltd. All rights reserved.
• Frank, D. C., Esper, J., Raible, C. C., Büntgen, U., Trouet, V., Stocker, B., & Joos, F. (2010). Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature, 463(7280), 527-530.
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  PMID: 20110999;Abstract: The processes controlling the carbon flux and carbon storage of the atmosphere, ocean and terrestrial biosphere are temperature sensitive and are likely to provide a positive feedback leading to amplified anthropogenic warming. Owing to this feedback, at timescales ranging from interannual to the 20-100-kyr cycles of Earth's orbital variations, warming of the climate system causes a net release of CO2 into the atmosphere; this in turn amplifies warming. But the magnitude of the climate sensitivity of the global carbon cycle (termed γ), and thus of its positive feedback strength, is under debate, giving rise to large uncertainties in global warming projections. Here we quantify the median γ as 7.7 p.p.m.v. CO2 per °C warming, with a likely range of 1.7-21.4 p.p.m.v. CO2 per °C. Sensitivity experiments exclude significant influence of pre-industrial land-use change on these estimates. Our results, based on the coupling of a probabilistic approach with an ensemble of proxy-based temperature reconstructions and pre-industrial CO2 data from three ice cores, provide robust constraints for γ on the policy-relevant multi-decadal to centennial timescales. By using an ensemble of > 200,000 members, quantification of γ is not only improved, but also likelihoods can be assigned, thereby providing a benchmark for future model simulations. Although uncertainties do not at present allow exclusion of γ calculated from any of ten coupled carbon-climate models, we find that γ is about twice as likely to fall in the lowermost than in the uppermost quartile of their range. Our results are incompatibly lower (P < 0.05) than recent pre-industrial empirical estimates of ∼40 p.p.m.v. CO2 per °C (refs 6, 7), and correspondingly suggest ∼80% less potential amplification of ongoing global warming. © 2010 Macmillan Publishers Limited. All rights reserved.
• Panayotov, M., Bebi, P., Trouet, V., & Yurukov, S. (2010). Climate signal in tree-ring chronologies of Pinus peuce and Pinus heldreichii from the Pirin mountains in Bulgaria. Trees - Structure and Function, 24(3), 479-490.
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  Abstract: Numerous proxy climate reconstructions have been developed for Europe, but there are still regions with limited data of this kind. One region is the Balkan Peninsula, which is characterized by complex interactions between mountains and climate. We present and discuss two tree-ring chronologies-a 758-year-long one of Pinus heldreichii Christ and 340-year-long one of Pinus peuce Griseb. from treeline locations in the Pirin Mountains in Bulgaria. Climate-growth relationships were computed with bootstrap correlation functions and their consistency over time assessed by calculating the correlations over shortened periods. In addition, we reviewed and analyzed climate situations in years with unusually narrow or wide tree rings. Both species were negatively influenced by previous summer drought conditions and cold winters. Early summer temperatures were positively correlated with P. peuce radial growth, whereas P. heldreichii displayed dependence on summer precipitation. In the second half of the twentieth century, the P. heldreichii trees displayed higher sensitivity to summer drought, which was probably a result of increased summer temperatures and decreased winter precipitation. Our findings contribute to more reliable proxy climate records for the region. © 2010 Springer-Verlag.
• Trouet, V., & Taylor, A. H. (2010). Multi-century variability in the Pacific North American circulation pattern reconstructed from tree rings. Climate Dynamics, 35(6), 953-963.
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  Abstract: We here present a reconstruction (1725-1999) of the winter Pacific North American (PNA) pattern based on three winter climate sensitive tree ring records from the western USA. Positive PNA phases in our record are associated with warm phases of ENSO and PDO and the reorganization of the PNA pattern towards a positive mode is strongest when ENSO and PDO are in phase. Regime shifts in our PNA record correspond to climatic shifts in other proxies of Pacific climate variability, including two well-documented shifts in the instrumental period (1976 and 1923). The correspondence breaks down in the early 19th century, when our record shows a prolonged period of positive PNA, with a peak in 1800-1820. This period corresponds to a period of low solar activity (Dalton Minimum), suggesting a 'positive PNA like' response to decreased solar irradiance. The distinct 30-year periodicity that dominates the PNA reconstruction in the 18th century and again from 1875 onwards is disrupted during this period. © 2009 Springer-Verlag.
• Trouet, V., Esper, J., & Beeckman, H. (2010). Climate/growth relationships of Brachystegia spiciformis from the miombo woodland in south central Africa. Dendrochronologia, 28(3), 161-171.
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  Abstract: We present five . Brachystegia spiciformis Benth. (BrSp) tree-ring chronologies from the seasonally dry miombo woodland in south central Africa. Between 9 and 34 stem discs were collected from three dry and two wet miombo sites. All samples showed distinct growth rings, which were marked by terminal parenchyma bands. Site chronologies varied in length between 43 and 149 years. An increase in the number of growth ring anomalies in older trees, however, resulted in an increase in dating error and a decrease in between-tree correlations with increase in the chronology length. Annual precipitation variability accounted for some 28% of the common variance in the BrSp chronologies and we found no difference in climate sensitivity between wet and dry miombo sites. The influence of climate, and of precipitation in particular, on tree growth was strongest at the core of the rainy season (December-February). This is also the time of the year when ENSO peaks in amplitude and ENSO effects on precipitation variability in southern Africa are the strongest. We found a negative response of tree growth to ENSO throughout most of the growth year, suggesting that the development of longer chronologies from the miombo region would allow for the investigation of temporal ENSO variability. A spatial extension of the miombo tree-ring network should therefore focus on regions where ENSO effects are the strongest (e.g., southeastern Africa). © 2009 Elsevier GmbH.
• Trouet, V., Taylor, A. H., Wahl, E. R., Skinner, C. N., & Stephens, S. L. (2010). Fire-climate interactions in the American West since 1400 CE. GEOPHYSICAL RESEARCH LETTERS, 37.
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  Despite a strong anthropogenic fingerprint on 20th Century wildland fire activity in the American West, climate remains a main driver. A better understanding of the spatiotemporal variability in fire-climate interactions is therefore crucial for fire management. Here, we present annually resolved, tree-ring based fire records for four regions in the American West that extend back to 1400 CE. In all regions, years with high fire activity were characterized by widespread yet regionally distinct summer droughts. Overall fire activity was high in late Medieval times, when much of the American West was affected by mega-droughts. A distinct decline in fire activity in the late 16th Century corresponds with anomalously low temperatures during the Little Ice Age and a decline in Native American fire use. The high spatiotemporal resolution of our fire record discloses a time-frequency dependent climatic influence on wildfire regimes in the American West that needs to be accounted for in fire models. Citation: Trouet, V., A. H. Taylor, E. R. Wahl, C. N. Skinner, and S. L. Stephens (2010), Fire-climate interactions in the American West since 1400 CE, Geophys. Res. Lett., 37, L04702, doi: 10.1029/2009GL041695.
• Friedrichs, D. A., Trouet, V., Büntgen, U., Frank, D. C., Esper, J., Neuwirth, B., & Löffler, J. (2009). Species-specific climate sensitivity of tree growth in Central-West Germany. Trees - Structure and Function, 23(4), 729-739.
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  Abstract: Growth responses to twentieth century climate variability of the three main European tree species Fagus sylvatica, Quercus petraea, and Pinus sylvestris within two temperate low mountain forest sites were analyzed, with particular emphasis on their dependence upon ecological factors and temporal stability in the obtained relationships. While site conditions in Central (~51°N, 9°E, KEL) and West (50.5°N, 6.5°E, EIF) Germany are similar, annual precipitation totals of ≅700 mm and ≅1,000 mm describe a maritime-continental gradient. Ring-width samples from 228 trees were collected and PCA used to identify common growth patterns. Chronologies were developed and redundancy analysis and simple correlation coefficients calculated to detect twentieth century temperature, precipitation, and drought fingerprints in the tree-ring data. Summer drought is the dominant driver of forest productivity, but regional and species-specific differences indicate more complex influences upon tree growth. F. sylvatica reveals the highest climate sensitivity, whereas Q. petraea is most drought tolerant. Drier growth conditions in KEL result in climate sensitivity of all species, and Q. petraea shifted from non-significant to significant drought sensitivity during recent decades at EIF. Drought sensitivity dynamics of all species vary over time. An increase of drought sensitivity in tree growth was found in the wetter forest area EIF, whereas a decrease occurred in the middle of the last century for all species in the drier KEL region. Species-specific and regional differences in long-term climate sensitivities, as evidenced by temporal variability in drought sensitivity, are potential indicators for a changing climate that effects Central-West German forest growth, but meanwhile hampers a general assessment of these effects. © Springer-Verlag 2009.
• Skinner, C. N., Abbott, C. S., Fry, D. L., Stephens, S. L., Taylor, A. H., & Trouet, V. (2009). Human and climatic influences on fire occurrence in California's North Coast Range, USA. Fire Ecology, 5(3), 76-99.
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  Abstract: Outside of the immediate coastal environments, little is known of fire history in the North Coast Range of California. Fire scar specimens were collected from ponderosa pine (Pinus ponderosa C. Lawson), sugar pine (Pinus lambertiana Douglas), incense cedar (Calocedrus decurrens [Torr] Florin), and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) for seven plots in mixed-conifer forests from the Mendocino National Forest, California, USA. Five plots were on high ridges immediately adjacent to the Sacramento Valley (DRY plots). The other two plots were on mesic north facing slopes interior in the range (MESIC plots), and were separated from the Sacramento Valley by at least one to several ridge systems. These two plots were selected because they supported populations of rare lady's slipper orchids (Cypripedium fasciculatum [Kellogg ex S. Watson] and C. montanum [Douglas ex Lindl.]). We found that DRY plots had unusually short fire return intervals (FRI) compared to other areas in northwestern California. The median FRI for these plots ranged from 4.5 yr to 6 yr in comparison with a tenth percentile of 11 yr, grand median of 24 yr, and ninetieth percentile of 66 yr for FRIs from other mixed conifer plots (n = 109) in the region. In northwestern California, most fire scars have been found primarily at ring boundary (68%) and secondarily in latewood (23%) with few in earlywood (9%). In contrast, in the DRY plots 35% (88) of the fire scars were in earlywood with only 15% (39) at the ring boundary. Fire occurrence was associated with drought conditions in the year of fire, and with wet conditions three years before the fire year. Before ~1850, fires that scarred at least two trees on a site were quite frequent for the DRY plots while being less frequent and more variable on the MESIC plots. However, the MESIC orchid habitats burned with frequency and seasonality similar to mixed conifer forests in the Klamath Mountains of northern California. Fires were less frequent after ~1850, with fires ceasing on most plots shortly after 1900. We suggest that these unusually low FRIs and high incidence of fire scars in earlywood were due to the adjacency of the DRY plots to the hot, relatively dry Sacramento Valley grasslands that were likely influenced by the burning practices of Native Americans.
• Trouet, V., & Baker, A. (2009). Reconstructing Climate Dynamics Over the Past Millennium: Synoptic‐Scale Climate Dynamics Over the Last Millennium: A Case Study for the MCA‐LIA Transition; Kippel, Switzerland, 17–20 May 2009. Eos, Transactions American Geophysical Union, 90(33), 283-283. doi:10.1029/2009eo330004
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  An increasing number of terrestrial and marine proxy records for temperature, hydrology, and oceanic circulation over the past millennium are becoming available, providing a reference frame for the assessment of current and future climate change. The spatial and temporal resolution of these proxies, however, is still limited, hindering the analysis of dynamical processes of regional to global climate changes. These processes can be simulated and interpreted using coupled climate models, which can also aid in separating externally forced climate signals (e.g., solar variability and anthropogenic forcing) from internal climate variability. Understanding of natural climate variability and underlying dynamics can be further improved by relating past variations to statistical models of climate processes.
• Trouet, V., & Baker, A. (2009). Reconstructing climate dynamics over the past millenniumxs. Eos, 90(33), 283-.
• Trouet, V., Esper, J., Graham, N. E., Baker, A., Scourse, J. D., & Frank, D. C. (2009). Persistent positive north atlantic oscillation mode dominated the medieval climate anomaly. Science, 324(5923), 78-80.
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  PMID: 19342585;Abstract: The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Niña-like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA.
• Trouet, V., Taylor, A. H., Carleton, A. M., & Skinner, C. N. (2009). Interannual variations in fire weather, fire extent, and synoptic-scale circulation patterns in northern California and Oregon. Theoretical and Applied Climatology, 95(3-4), 349-360.
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  Abstract: The Mediterranean climate region on the west coast of the United States is characterized by wet winters and dry summers, and by high fire activity. The importance of synoptic-scale circulation patterns (ENSO, PDO, PNA) on fire-climate interactions is evident in contemporary fire data sets and in pre-Euroamerican tree-ring-based fire records. We investigated how interannual variability in two fire weather indices, the Haines index (HI) and the Energy Release Component (ERC), in the Mediterranean region of southern Oregon and northern California is related to atmospheric circulation and fire extent. Years with high and low fire weather index values corresponded to years with a high and low annual area burned, respectively. HI combines atmospheric moisture with atmospheric instability and variation in HI was more strongly associated with interannual variation in wildfire extent than ERC, which is based on moisture alone. The association between fire extent and HI was also higher for fires in southern Oregon than in northern California. In terms of synoptic-scale circulation patterns, years of high fire risk (i.e., increased potential for erratic fire behavior, represented by HI and ERC) were associated with positive winter PNA and PDO conditions, characterized by enhanced regional mid-tropospheric ridging and low atmospheric moisture. The time lag we found between fire risk potential and prior winter circulation patterns could contribute to the development of long-lead fire-climate forecasting. © Springer-Verlag 2008.
• Taylor, A. H., Trouet, V., & Skinner, C. N. (2008). Climatic influences on fire regimes in montane forests of the southern Cascades, California, USA. International Journal of Wildland Fire, 17(1), 60-71.
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  Abstract: The relationship between climate variability and fire extent was examined in montane and upper montane forests in the southern Cascades. Fire occurrence and extent were reconstructed for seven sites and related to measures of reconstructed climate for the period 1700 to 1900. The climate variables included the Palmer Drought Severity Index (PDSI), summer temperature (TEMP), NINO3, a measure of the El Niño?Southern Oscillation (ENSO), and the Pacific Decadal Oscillation (PDO). Fire extent at the site and regional scale was associated with dry and warm conditions in the year of the fire and regional fire extent was not associated with ENSO or PDO for the full period of analysis. The relationship between regional fire extent and climate was not stable over time. The associations of fire extent with PDSI and TEMP were only significant from ∼1775 onward and the associations were strongest between 1805 and 1855. PDO and fire extent were also associated during the 1805?1855 period, and ENSO was associated with fire extent before 1800, but not after. The interannual and interdecadal variability of the fire response to temperature and drought suggests that increased periods of regional fire activity may occur when high interannual PDSI variation coincides with warm decades. © IAWF 2008.
• Yuan, Y., Shao, X., Wei, W., Shulong, Y. u., Gong, Y., & Trouet, V. (2007). The potential to reconstruct Manasi River streamflow in the Northern Tien Shan Mountains (NW China). Tree-Ring Research, 63(2), 81-93.
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  Abstract: We present a tree-ring based reconstruction of water-year (October-September) streamflow for the Manasi River in the northern Tien Shan mountains in northwestern China. We developed eight Tien Shan spruce (Picea schrenkiana Fisch, et Mey.) chronologies for this purpose, which showed a common climatic signal. The hydroclimatic forcing driving tree growth variability affected streamflow with a three- to four-year lag. The model used to estimate streamflow is based on the average of three chronologies and reflects the autoregressive structure of the streamflow time series. The model explains 51% of variance in the instrumental data and allowed us to reconstruct streamflow for the period 1629-2000. This preliminary reconstruction could serve as a basis for providing a longer context for evaluating the recent (1995-2000) increasing trends in Manasi River streamflow and enables the detection of sustained periods of drought and flood, which are particularly challenging for managing water systems. Several of the reconstructed extended dry (wet) periods of the Manasi River correspond to reconstructed periods of drought (flood) in Central Asia in general and in other Tien Shan mountain locations in particular, suggesting that the analysis of Tien Shan spruce could contribute significantly to the development of regionally explicit streamflow reconstructions. Copyright © 2007 by The Tree-Ring Society.
• Trouet, V., Coppin, P., & Beeckman, H. (2006). Annual growth ring patterns in Brachystegia spiciformis reveal influence of precipitation on tree growth. Biotropica, 38(3), 375-382.
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  Abstract: The availability of exactly dated tree-ring chronologies is limited in tropical regions. However, these chronologies could contribute widely to studies of the influence of natural and human-induced factors on tropical forests. We examine the potential for building a chronology based on three sites in the miombo woodland of western Zambia. Brachystegia spiciformis Benth., a dominant species from this vegetation type, is used. Response of the chronology to several climatic factors is examined. All specimens showed very clear growth rings, and cross-dating between radii of a tree was successful for all trees. Site chronologies could be constructed after cross-dating of growth ring series of individual trees. The mean growth ring curves of the three sites were significantly similar, allowing for the construction of a regional chronology. Correlation function analysis between the tree-ring chronology and regional climatic variables revealed that climate at the core of the rainy season, in December and January, has an explicit influence on tree growth. Where precipitation and relative humidity in these months influence tree growth positively, temperature correlates in a negative way. Some 20 percent of the variance in the B. spiciformis tree-ring chronology is accounted for by wet season rainfall. The successful cross-dating and correlation between a tree-ring chronology and climate demonstrated in this study indicate annual ring formation in B. spiciformis trees and sensitivity to climatic conditions. © 2006 by The Association for Tropical Biology and Conservation.
• Trouet, V., Taylor, A. H., Carleton, A. M., & Skinner, C. N. (2006). Fire-climate interaction in forests of the American Pacific coast. Geophysical Research Letters, 33(18).
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  Abstract: We investigate relationships between climate and wildfire activity between 1929 and 2004 in Pacific coast forests of the United States. Self-Organizing Mapping (SOM) of annual area burned in National Forests (NF) in California, Oregon, and Washington identifies three contiguous NF groups and a fourth group of NF traversed by major highways. Large fire years in all groups are dry compared to small fire years. A sub-hemispheric circulation pattern of a strong trough over the North Pacific and a ridge over the West Coast is characteristic of large fire years in all groups. This pattern resembles the Pacific North American (PNA) teleconnection and positive phase of the Pacific Decadal Oscillation (PDO). A reverse PNA and negative PDO phase characterizes small fire years. Despite the effect of fire suppression management between 1929 and 2004, forest area burned is linked to climatic variations related to large-scale atmospheric circulation patterns. Copyright 2006 by the American Geophysical Union.
• Fichtler, E., Trouet, V., Beeckman, H., Coppin, P., & Worbes, M. (2004). Climatic signals in tree rings of Burkea africana and Pterocarpus angolensis from semiarid forests in Namibia. Trees - Structure and Function, 18(4), 442-451.
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  Abstract: Tree-ring studies contribute worldwide to the understanding of climate and its relation to tree growth. Long tree-ring chronologies serve as climate proxies for the reconstruction of past, pre-instrument climate and its recent change. In tropical regions, the availability of exactly dated tree-ring chronologies is limited. The dendroclimatic potential of two dominant species from dry forests in northern Namibia was examined in the study presented in this paper. Both species (Burkea africana Hook and Pterocarpus angolensis DC) were sampled at two sites (ca. 900 km apart), and the response to several climatic variables, including ENSO indices, is studied. All specimens showed distinct growth rings and cross-dating between radii was successful for all trees. Species-specific mean curves were built for both sites. The mean curves of different species of the same site synchronised significantly, allowing the construction of a site-specific chronology. Synchronisation between sites was not possible, but spectral analysis of the chronologies implied that both show similar long-term (6.7 year) oscillation patterns. B. africana is more sensitive to rainfall variation than P. angolensis at both sites. Growth response to rainfall was positive, but a time-lag in the reaction occurred between the sites, corresponding to the time-lag of the beginning of the rainy season. Air temperature showed a negative correlation with stem increment at both sites. The response at the westernmost site to two ENSO indices indicates a tree growth decrease during El Niño years, which are generally dry in southern Africa. © Springer-Verlag 2004.
• Trouet, V., Coppin, P., & Beeckman, H. (2003). Dendroclimatological potential of the miombo woodland in Zambia. Trace.
• Trouet, V., Haneca, K., Coppin, P., & Beeckman, H. (2001). Tree ring analysis of Brachystegia spiciformis and Isoberlinia tomentosa: Evaluation of the enso-signal in the miombo woodland of eastern Africa. IAWA Journal, 22(4), 385-399.
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  Abstract: The value of growth rings as proxy data for climate reconstruction was studied in two miombo woodland species in eastern Africa. Growth rings, marked by terminal parenchyma, were visually detectable on carefully prepared stem discs of Isoberlinia tomentosa and Brachystegia spiciformis, dominant species of the miombo woodland in north-western Tanzania. However, the presence of multiple growth ring anomalies rendered cross-dating of the growth ring series between trees difficult. Cross-dating succeeded for eight out of thirteen samples for Isoberlinia tomentosa, but was unsuccessful for Brachystegia spiciformis. A mean series of 38 years was calculated for Isoberlinia tomentosa only. Monthly precipitation, monthly maximum air temperature and monthly SOI-value (Southern Oscillation Index) correlated significantly with tree ring widths of the mean series. These correlations are strong indicators of the annual character of the growth rings. They also suggest that Isoberlinia tomentosa provides an appropriate paleoclimatic record for dendroclimatic reconstruction.

Proceedings Publications

• Hudson, A. R., Alfaro-Sanchez, R., Belmecheri, S., Moore, D. J., & Trouet, V. M. (2017, DEC). PP51C-1077: Summer Temperature Extremes in the Northern Rockies: A Tree-Ring-Based Reconstruction (1670-2014) from the Bighorn Mountains, WY. In AGU Fall Meeting, Proceedings.
• Klippel, L., Krusic, P., Hartl-Meier, C., Trouet, V. M., & Esper, J. (2016, fall). High-elevation inter-site differences in Mount Smolikas tree-ring width data. In TRACE2016.

Presentations

• Trouet, V. M. (2022). Tree Story. Department of Biology Seminar seriesKent State University.
• Trouet, V. M. (2023). Tree Story. Department of Biology seminar seriesBowdoin College.
• Trouet, V. M. (2023). Tree Story. Department of BiologyVrije Universiteit Brussel, Belgium.
• Trouet, V. M. (2023). Tree Story. Department of Geology annual invited lectureGhent University, Belgium.
• Trouet, V. M. (2023). Tree Story. Doctor Honoris CausaWageningen University and Research.
• Trouet, V. M. (2023). Tree Story. Geosciences departmentKatholieke Universiteit Leuven, Belgium.
• Babst, F., & Trouet, V. M. (2021, 04). Dry-season climate drives interannual variability in tropical tree growth. European Geosciences Union General Assembly. Vienna.
• Dorado-Liñan, I., Ayarzaguena, B., Xu, G., & Trouet, V. M. (2021, april). Jet stream position connected to atmospheric blocking drives regional anomalies in European forest productivity. EGU annual conference. online.
• Trouet, V. M. (2021, April). Wat bomen ons vertellen. BOS+, Belgium, lecture series. virtual: BOS+, Belgium (community forestry organization).
• Trouet, V. M. (2021, December). Tree story: the history of the world written in rings. International Society of Arbiculture annual meeting. virtual: International Society of Arbiculture.
• Trouet, V. M. (2021, February). Wat bomen ons vertellen. Limburgse Koepel voor Natuurstudie, Belgium, lecture series. virtual: Limburgse Koepel voor Natuurstudie, Belgium (Limburg Nature Study organization).
• Trouet, V. M. (2021, June). Diversity in Dendrochronology. TRACE conference (keynote). online.
• Trouet, V. M. (2021, June). Wat bomen ons vertellen. Vereniging Stadswerk Nederland, lecture series. virtual: Vereniging Stadswerk Nederland, The Netherlands (Dutch Municipal Association).
• Trouet, V. M. (2021, March). A tree-ring perspective on fire and climate dynamics. Goddard Scientific Colloquium, NASA Goddard. online.
• Trouet, V. M. (2021, March). A tree-ring perspective on fire and climate dynamics. Institute of Botany, Czech Academy of Sciences, seminar series. online.
• Trouet, V. M. (2021, March). Klimaat en Spel. deBuren, lecture series. virtual: deBuren, Belgium & The Netherlands (Flemish-Dutch culture & debate organization).
• Trouet, V. M. (2021, May). A paleoclimate perspective on large-scale climate dynamics. Perspectives on Climate Science, EGU. online.
• Trouet, V. M. (2021, November). Diversity in Dendrochronology. Tree-ring Talk, LTRR. online.
• Trouet, V. M. (2021, November). Tree Story: What we can learn about climate and forest history from the rings in trees. EEB departmental seminar, Cornell University. Ithaca, NY (online).
• Trouet, V. M. (2021, November). Tree Story: what we can learn about human, climate, and forest history from the rings in trees. Biology Departmental Seminar, University of Miami. Miami, FL (online).
• Trouet, V. M. (2021, November). Tree story: the history of the world written in rings. Landscape Inspectors Association Florida. virtual: Landscape Inspectors Association Florida.
• Trouet, V. M. (2021, October). Tree story: the history of the world written in rings. Trees South Carolina. virtual: Trees South Carolina.
• Trouet, V. M. (2021, October). Wat bomen ons vertellen. Gallo-Romeins Museum Tongeren, lecture seriesGallo-Romeins Museum Tongeren, Belgium (Gallo-Roman Museum).
• Trouet, V. M. (2021, October). Wat bomen ons vertellen. Koninklijke Nederlandse Natuur Vereniging, lecture series. virtual: Koninklijke Nederlandse Natuur Vereniging, Wageningen, The Netherlands (Royal Dutch Nature Association).
• Xu, G., Meko, M., Klippel, L., Dorado-Liñan, I., & Trouet, V. M. (2021). Europe-Atlantic jet caused dipole mode of European climate and increased climatic extremes. EGU annual meeting. online.
• Dorado-Linan, I., & Trouet, V. M. (2020, May). North Atlantic Jet position induces latitudinal decouplings in forest productivity in Europe. EGU meeting 2020. Vienna, Austria (virtual): European Geophysical Union.
• Trouet, V. M. (2020, February). Tree Story: What we can learn about climate history from the rings in trees. Environmental History Seminar. Washington DC: Georgetown University.
• Trouet, V. M. (2020, January). Reduced Caribbean Hurricane Activity during the Maunder Solar Minimum. Sun-Climate Symposium. Tucson, AZ: Solar Radiation and Climate Experiment (SORCE).
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• Trouet, V. M. (2020, July). The impact of climate change on wildfires. Kavli Frontiers in Science Symposium. Seattle, WA (virtual): Kavli Foundation/National Academy of Sciences.
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• Trouet, V. M. (2020, November). A paleoclimate perspective on large-scale climate dynamics. Biology and Paleo Environment Seminar series. Palisades, NY (virtual): Lamont-Doherty Earth Observatory.
• Trouet, V. M. (2020, may). The Impact of Climate Change on California Wildfires. Climate seminar. Brussels, Belgium (virtual): Royal Belgian Institute for Space Aeronomy.
• Zuidema, P., Groenendijk, P., Trouet, V. M., & Babst, F. (2020, May). Sensitivity of tropical tree growth to climatic variation: a global meta-analysis of tree-ring data. EGU meeting 2020. Vienna, Austria (virtual): European Geophysical Union.
• Klippel, L., Trouet, V. M., & Esper, J. (2019, May). A 1200+ year reconstruction of temperature extremes for the northeastern Mediterranean region. Tree Rings in Archeology, Climatology, and Ecology (TRACE) conference. Caserta, Italy: ATR.
• Trouet, V. M. (2019, December). Eight Hundred Years of North Atlantic Jet Stream Variability and its Influence on European Climate Extremes. AGU Annual Meeting. San Francisco, CA: AGU.
• Trouet, V. M. (2019, February). A paleoclimate perspective on large-scale climate dynamics. Frontiers in Earth System Science seminar. New Brunswick, NJ: Rutgers University.
• Trouet, V. M. (2019, March). Natural drivers of early spring Northern Hemisphere tropical belt movements over the past 800 years. ClimaTea seminar. Cambridge, MA: Harvard University.
• Trouet, V. M. (2019, May). Reconstructing jet stream and Hadley Cell circulation dynamics. Tree Rings in Archeology, Climatology, and Ecology (TRACE) conference. Caserta, Italy: ATR.
• Trouet, V. M. (2019, May). Shipwrecks, Tree Rings, and Hurricanes. Creating Nature: Premodern Climate and the Environmental Humanities conference. Washington, DC: Folgers Library.
• Trouet, V. M. (2019, November). A paleoclimate perspective on large-scale climate dynamics. Geology Research Seminar. Ghent, Belgium: Ghent University.
• Trouet, V. M. (2019, November). Paleoklimaat: klimaatsverandering in de context van de laatste 1000 jaar. Lessen voor de XXIe Eeuw (Lessons for the 21st century) seminar series. Leuven, Belgium: KULeuven.
• Trouet, V. M. (2019, October). A paleoclimate perspective on large-scale climate dynamics. Climate, People, and Environment (CPEP) seminar. Madison, WI: University of Wisconsin.
• Zuidema, P., Babst, F., Trouet, V. M., & Groenendijk, P. (2019, May). Warm and dry years limit tropical and subtropical tree growth globally. Tree Rings in Archeology, Climatology, and Ecology (TRACE) conference. Caserta, Italy: ATR.
• Trouet, V. M. (2018, April). Treestory: a history of people and climate ingrained in trees. UA Udall Center seminar series. Tucson, AZ.
• Trouet, V. M. (2018, August). Northern Hemisphere tropical belt movements over the past 800 years. Canadian/American Quaternary Association (AMQUA). Ottawa, Canada: AMQUA.
• Trouet, V. M. (2018, February). Heat, Wind, and Fire: extreme climate events in a historical content. Brown University seminar series. Providence, RI: Brown University.
• Trouet, V. M. (2018, February). Heat, Wind, and Fire: extreme climate events in a historical content. McGill University, Physics seminar series. Montreal, Canada: McGill University.
• Trouet, V. M. (2018, February). Heat, Wind, and Fire: extreme climate events in a historical content. UA Environmental Breakfast Club. Tucson, AZ: UA Environmental Breakfast Club.
• Trouet, V. M. (2018, February). Heat, Wind, and Fire: extreme climate events in a historical content. Vischer Lecture (invited). Bloomington, Indiana: Indiana University, Department of Geography.
• Trouet, V. M. (2018, November). Recent enhanced jet stream variance leads to more frequent mid-latitude weather extremes. Human Challenges in Extreme Environments, UA. Tucson, AZ: UA Udall Center.
• Trouet, V. M., Alfaro-Sanchez, R., & Monson, R. K. (2018, December). A tree-ring based reconstruction of spring Northern Hemisphere tropical belt movements over the past 800 years. AGU Annual Meeting. Washington DC: AGU.
• Trouet, V. M., Babst, F., & Meko, M. (2018, February). Recent enhanced high-summer North Atlantic Jet (NAJ) variability emerges from three-century context. LTRR, Tree-Ring Talk. Tucson, AZ.
• Zamora-Reyes, D., Trouet, V. M., Black, B., & van der Sleen, P. (2018, Dec). Enhanced climatic variability over California post-1950: A synthesis of observed and reconstructed trends and possible explanations. American Geophysical Union annual meeting. Washington, DC.
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  Diana presented this talk at AGU 2018
• Frank, D. C., Friend, A., Girardin, M., Mahecha, M., Bodesheim, P., Klesse, S., Bjorklund, J., Seftigen, K., Enquist, B. J., Record, S., Charney, N., Evans, M. E., Trouet, V. M., Zhang, Z., Poulter, B., Bouriaud, O., & Babst, F. (2017, April). When tree rings go global: challenges and opportunities for retro- and prospective insights. European Geosciences Union General Assembly. Vienna, Austria: European Geosciences Union.
• Trouet, V. M. (2017, April). Snow, wind, and fire: tree rings as recorders of past extreme climate events. Institute for Geophysics, University of Texas. Austin, TX: University of Texas.
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  Invited presentation
• Trouet, V. M. (2017, September). Heat, wind, and fire: understanding drivers of past climate variability and extremes. St. Petersburg Coastal and Marine Science Center, USGS. St. Petersburg, FL: USGS.
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  Invited seminar lecture
• Alexander, M. R., & Trouet, V. M. (2016, December). Stand structure and composition provide differential tree-ring growth signals in eastern U.S. forests. AGU Fall meeting. San Francisco, CA: AGU.
• Alexander, M. R., Rollinson, C., Pederson, N., & Trouet, V. M. (2016, April). Co ‐ varying influences on growth of eastern U.S. deciduous hardwood trees. Ameridendro. Mendoza, Argentina.
• G, G., & Trouet, V. M. (2016, April). Hydroclimatic variability of the Baja California Peninsula reconstructed from tree ‐ rings of Pinus lagunae and Pinus monophylla. Ameridendro. Mendoza, Argentina.
• Gutierrez Garcia, G., Carriquiry-Beltran, J. D., Leavitt, S. W., & Trouet, V. M. (2016, March). Hydroclimatic variability of the Baja California Peninsula reconstructed from tree-rings of Pinus lagunae and Pinus monophylla. Third American Dendrochronology Conference (AmeriDendro). Mendoza, Argentina.
• P, S., & Trouet, V. M. (2016, April). Latitudinal gradients in the stable carbon and oxygen isotopes of tree ‐ ring cellulose reveal differential climate influences of the North American Monsoon syste. Ameridendro. Mendoza, Argentina.
• Szejner, P., & Trouet, V. M. (2016, December). Latitudinal Gradients in Tree Ring Stable Carbon and Oxygen Isotopes Reveal Differential Climate Influences of the North American Monsoon System. AGU Fall meeting. San Francisco, CA: AGU.
• Szejner, P., Wright, W. E., Babst, F., Belmecheri, S., Trouet, V. M., Leavitt, S. W., Ehleringer, J. R., & Monson, R. K. (2016, December). Latitudinal gradients in tree ring stable carbon and oxygen isotopes reveal differential climate influences of the North American Monsoon system. AGU Fall Meeting. San Francisco, CA: American Geophysical Union.
• Trouet, V. M. (2016, December). The Trouet Lab. LTRR latewood seminar series. LTRR: LTRR, UA.
• Trouet, V. M. (2016, February). Tree-ring based reconstruction of Northern Hemisphere Jetstream variability and its ecosystem impacts. UA Geosciences. Tucson, AZ: UA Geosciences.
• Trouet, V. M. (2016, March). Tree-ring based reconstruction of Northern Hemisphere Jetstream variability and its ecosystem impacts. UA Soil, Water, and Environmental Science seminar series. Tucson, AZ: UA SWES.
• Trouet, V. M. (2016, November). Influence of the North Pacific Jet stream on California hydroclimate and wildfire regimes over the last 500 years. Kavli Frontiers in Science Symposium. Irvine, CA: Kavli Foundation/National Academy of Sciences.
  More info

  http://www.kavlifoundation.org/kavli-frontiers-science
• Trouet, V. M. (2016, November). Influence of the North Pacific Jet stream on California hydroclimate and wildfire regimes over the last 500 years. UA Hydrology and Atmospheric Sciences seminar series. Tucson, AZ: UA HAS.
• Trouet, V. M. (2016, October). Influence of the North Pacific Jet stream on California hydroclimate and wildfire regimes over the last 500 years. Department of Forestry, Universite de Quebec en Abitibi-Témiscamingue. Rouyn-Noranda, Canada: Department of Forestry, Universite de Quebec en Abitibi-Témiscamingue.
• Trouet, V. M. (2016, September). A tree-ring based reconstruction of Northern Hemisphere Jet variability and its ecosystem impacts. Division of Forest, Nature, and Landscape, Katholieke Universiteit Leuven. Leuven, Belgium: Division of Forest, Nature, and Landscape, Katholieke Universiteit Leuven.
• Trouet, V. M., & Babst, F. (2016, September). A tree-ring based reconstruction of North Atlantic Jet variability over the last 250 years. SCOT2K workshop. Aviemore, Scotland: SCOT2K.
• Trouet, V. M., Harley, G., & Dominguez-Delmas, M. (2016, February). Shipwreck rates reveal North Atlantic tropical cyclone response to past solar forcing. UA Geography seminar series. Tucson, AZ: UA Geography.
• Trouet, V. M., Taylor, A., Skinner, C., & Stephens, S. (2016, December). Socio-ecological transitions trigger fire regime shifts and modulate fire-climate interactions in the Sierra Nevada, CA, 1600-2015 CE. AGU Fall meeting. San Francisco, CA: AGU.
• Trouet, V. M., Wahl, E. R., Taylor, A. H., & Zorita, E. (2016, April). Influence of the North Pacific Jet stream on California hydroclimate and wildfire regimes over the last 500 years. Ameridendro. Mendoza, Argentina.
• Zorita, E., Wahl, E. R., & Trouet, V. M. (2016, April). Reconstructions of Circulation in the Northeastern Pacific and Western North America since 1500 A.D.: Relation to Precipitation and Fire Conditions in California. EGU annual meeting. Vienna, Austria: EGU.
• Friend, A., Babst, F., Belmecheri, S., Frank, D., Pain, A., Hayat, A., Poulter, B., Rademacher, T., & Trouet, V. M. (2015, December). Using Novel Approaches in Process-Based Modeling for Interpreting Inter-Annual Variability in Tree Ring Widths, Wood Density Profiles, and Cellulose Isotopic Ratios. AGU Fall meeting. San Francisco, CA: AGU.
• Trouet, V. M., & Khamisi, Z. H. (2015, MAY). Climatic drivers of tree growth in the miombo woodland of southern Africa. XYLAREDD conference. Tervuren, Belgium: Africamuseum, Belgium.
• Trouet, V. M., Babst, F., Alexander, M. R., Black, B., Szejner, P., bouriaud, O., Klesse, S., Roden, J., Ciais, P., Poulter, B., Frank, D., & Moore, D. J. (2015, August). A tree-ring perspective on terrestrial climate dynamics. ESA annual meeting. Baltimore, MD: ESA.
• Trouet, V. M., Belmecheri, S., Babst, F., Wahl, E., & Stahle, D. (2015, December). Multi-century Evaluation of Sierra Nevada Snowpack. AGU Fall meeting. San Francisco, CA: AGU.
• Trouet, V. M., Harley, G., & Dominguez Delmas, M. (2015, June). Shipwreck rates reveal tropical cyclone response to radiative forcing. 5th International Summit on Hurricanes and Climate Change. Chania, Crete, Greece: Aegean conferences.
• Trouet, V. M., Harley, G., & Dominguez-Delmas, M. (2015, October). Shipwreck rates reveal North Atlantic tropical cyclone response to past radiative forcing. UA Hydrology and Atmospheric Sciences seminar series. Tucson, AZ: UA HAS.
• Wahl, E., Zorita, E., Trouet, V. M., & Diaz, H. (2015, December). 500-year Reconstructions of Circulation in the Northeastern Pacific and Western North America: Relation to Precipitation and Fire Conditions in California and Precipitation in Hawai'i. AGU Fall meeting. San Francisco, CA: AGU.
• Trouet, V. M. (2014, January). Climate Dynamics and European History. 9th International Conference on Dendrochronology. Melbourne, Australia.
• Trouet, V. M. (2014, May). Potential pathways of climatic influence on the late Roman Empire. Center for the Ancient Mediterranean workshop. Columbia University, NY: Columbia University, NY.
• Trouet, V. M. (2014, May). Reconstructing the position of the North Atlantic Jet. Physical Oceanography and Climate Change seminar series. Bangor, Wales: University of Wales, Bangor (UK).
• Trouet, V. M. (2014, September). Reconstructing North Pacific Jet variability and its influence on Sierra Nevada fire regimes. MTNCLIM 2014 Conference, Cirmount. Midway, UT: Cirmount.
• Trouet, V. M., & Babst, F. (2014, January). North Pacific Jet variability over the last 600 years. 9th International Conference on Dendrochronology. Melbourne, Australia.
• Trouet, V. M., Harley, G., & Dominguez-Delmas, M. (2014, October). Florida tree rings and shipwreck rates reflect Caribbean hurricane activity since 1500CE. LTRR Tree-Ring Talk seminar series. Tucson, AZ: LTRR.

Poster Presentations

• De Mil, T., Salzer, M., Pearson, C. L., Trouet, V. M., & Van den Bulcke, J. (2020, May). Maximum latewood density records of the oldest trees in the world: Great Basin Bristlecone pine (Pinus Longaeva). EGU meeting 2020. Vienna, Austria (virtual): EGU.
• De Mil, T., Salzer, M., Pearson, C. L., Trouet, V. M., & Van den Bulcke, J. (2020, december). Maximum latewood density records of Great Basin Bristlecone pine (Pinus Longaeva) in the White Mountains, California. AGU Fall meeting 2020. San Francisco, CA (virtual): AGU.
• Trouet, V. M., De Mil, T., Meko, M., & Van den Bulcke, J. (2020, May). Exploring the climate signal in tree-ring density of Clanwilliam cedar, South Africa. EGU meeting 2020. Vienna, Austria (virtual): European Geophysical Union.
• Xu, G., Trouet, V. M., Guiterman, C., Swetnam, T., Anchukaitis, K. J., & Baisan, C. (2020, december). Fire and climate in the eastern Siberia over the past 500 years (1500-2010 CE). AGU Fall meeting 2020. San Francisco, CA (virtual): AGU.
• De Mil, T., & Trouet, V. M. (2019, december). Towards a Temperature Reconstruction for Southern Africa: Exploring the Climate Signal in Tree-Ring Density of Clanwilliam Cedar from South Africa. AGU 2019. San Francisco, CA: AGU.
• Hudson, A., & Trouet, V. M. (2019, december). Seasonal jet stream controls on surface climate influence the timing of plant growth: a mechanistic perspective on landscape phenology shifts in a warming world. AGU 2019. San Francisco, CA: AGU.
• Meko, m., & Trouet, V. M. (2019, december). Lura Lakes, Albania Tree-ring Maximum Latewood Density Temperature Proxy. AGU 2019. San Francisco, CA: AGU.
• Thapa, U., Trouet, V. M., & StGeorge, S. (2019, december). Poleward Excursions of the Himalayan Sub-tropical Jet during the Past Four Centuries. AGU 2019. San Francisco, CA: AGU.
• Xu, G., & Trouet, V. M. (2019, december). Intra-annual tree-ring δ18O and δ13C as ecophysiological indicators for tree growth in Southeastern China. AGU 2019. San Francisco, CA: AGU.
• Zamora-Reyes, D., & Trouet, V. M. (2019, december). Understanding the Recent Enhancement in Precipitation Variability over California. AGU 2019. San Francisco, CA: AGU.
• Alexander, R. M., & Trouet, V. M. (2018, August). Don’t forget the little guys: Understory trees show dynamic climate sensitivity in northeastern US forests. ESA meeting.
• Babst, F., & Trouet, V. M. (2018, August). When tree rings go global: Challenges and opportunities for retro- and prospective insight. ESA meeting.
• Hudson, A., & Trouet, V. M. (2018, december). When and where are plants responding to synoptic circulations?. AGU 2018.
• Meko, m., & Trouet, V. M. (2018, december). Broad-scale and local drivers of pre-instrumental summer temperature extremes in the central Balkan region from tree-ring records. AGU 2018.
• Oita, S., Trouet, V. M., Uren, J. M., & Arnold, A. E. (2018, August). Relationships of foliar endophyte communities in Picea mariana to tree age, biomass, and latitude. International Symbiosis Society.
• Xu, G., & Trouet, V. M. (2018, december). Intra-annual tree-ring δ18O variations in subtropical China reflect seasonal transitions in climate response. AGU 2018.
• Zamora-Reyes, D., & Trouet, V. M. (2018, december). Enhanced climatic variability over California post-1950: A synthesis of observed and reconstructed trends and possible explanations. AGU 2018.
• Ehleringer, J., Trouet, V. M., Leavitt, S. W., Hughes, M. K., Babst, F., Wright, w., Morino, K., Belmecheri, S., Szejner, P., & Monson, R. K. (2017, August). Reconstructing drought legacies in the North American Monsoon climate system using tree ring stable isotopes. ESA meeting. Portland, OR.
• Hudson, A., Alfaro-Sanchez, R., Belmecheri, S., Moore, D. J., & Trouet, V. M. (2017, December). Summer Temperature Extremes in the Northern Rockies: A Tree-Ring-Based Reconstruction (1670-2014) from the Bighorn Mountains, WY. AGU Fall Meeting. New Orleans, LA: American Geophysical Union.
• Meko, M., Trouet, V. M., Panayotov, M., & Frank, D. C. (2017, December). A 650-year record of past summer temperatures from Pirin, Bulgaria tree-ring density. AGU Fall Meeting. New Orleans, LA: American Geophysical Union.
• Trouet, V. M., Babst, F., & Meko, M. (2017, December). Recent Increase in North Atlantic Jet Variability Emerges from Three-Century Long Context (Invited). AGU Fall Meeting. New Orleans, LA: American Geophysical Union.
  More info

  invited presentation but turned into poster because too few submissions to session
• Hudson, A. R., Trouet, V. M., Belmecheri, S., & Moore, D. J. (2016, Fall). Validating the Spring Jet Stream Indices Using Extended Spring Index (SI-x) Models. American Geophysical Union. San Francisco: AGU.
• Meko, M., & Trouet, V. M. (2016, May). Multi-parameter dendrochronology in sub-saharan Africa. TRACE2016. Poland: Association of Tree-Ring Research.
• Alexander, M. R., Babst, F., Montane, F., Trouet, V. M., & Moore, D. J. (2015, Jan). Eddy Meets Dendro: Carbon Allocation in Two Contrasting Forest Ecosystems. 5th North American Carbon Program Principle Investigators Meeting.. Washington, D.C.: North American Carbon Program.
• Belmecheri, S., Babst, F., Trouet, V. M., & Betancourt, J. (2015, December). 20th Century Northern hemisphere jet stream variability. AGU Fall Meeting. San Francisco, CA: AGU.
• Harley, G., Trouet, V. M., & Dominguez-Delmas, M. (2014, December). Shipwreck rates and tree rings suggest reduced North Atlantic tropical cyclone activity during the Maunder Minimum. AGU Fall Meeting. San Francisco, CA: AGU.
• Trouet, V. M., & Babst, F. (2014, December). A tree-ring based reconstruction (1725-present) shows a 20th century northward shift in the position of the summer North Atlantic Jet. AGU Fall Meeting. San Francisco, CA: AGU.
• Alexander, R., Trouet, V. M., Babst, F., & Moore, D. J. (2013, Feb). Hydrologically-driven spatial heterogeneity of tree productivity in the Southwest.. North American Carbon Program All Investigators Meeting. Albuquerque, NM: North American Carbon Program.
  More info

  We here present an empirical assessment of hydrologically-driven spatial heterogeneity of forest productivity and climate sensitivity in the Southwest. Concretely, we aim to:1. Investigate the influence of hydrologically-driven microclimate variability on tree productivity by combining spatially explicit hydrological and topographic data with tree-ring and fluxtower-based NPP quantifications;2. Investigate the influence of hydrologically-driven microclimate variability on tree climate sensitivity by measuring a suite of tree-ring parameters and linking them to climate data;First, we apply a NPP-focused tree-ring sampling approach to three intensive research sites within the Jemez River Basin Critical Zone Observatory (JRB-CZO). Tree-ring data offer a valuable archive to validate and improve NPP estimations and we here integrate them with high spatial resolution hydrological data to improve our process-based understanding of the water-carbon nexus. We use site-specific flux-tower measurements as a benchmark for our tree-ring based NPP estimates.Furthermore, we measure a suite of tree-ring parameters that can provide complimentary climatic information: tree ring width in the Southwest is primarily driven by water availability, whereas maximum latewood density measurements can reflect temperature variability, and stable carbon and oxygen isotope composition can provide information about water source region. Understanding how each of these tree-ring parameters varies with microclimate conditions provides us with holistic and detailed insight in the hydrological and climatic drivers of tree growth and productivity in the Southwest.In a second step, we extrapolate tier-one findings across the JRB-CZO using an existing network of tree-ring series to test microclimate-dependent sensitivity and productivity across a wide range of site conditions and thus to link the rich paleo-drought record of the Southwest with methods to understand and predict the impact of changing hydrological conditions on plant productivity. This record represents a data constrained historical description of the spatial variability in water supply in Arizona and New Mexico.

Creative Productions

• Trouet, V. M. (2020. Tree Rings as Soothsayers. The Scientist. https://theconversation.com/shipwreck-records-and-tree-rings-unveil-caribbean-hurricane-history-and-clues-to-the-future-55730
  More info

  I was invited to write a piece about our PNAS paper for the scientific outreach website The Conversation.
• Trouet, V. M., Harley, G. L., & Dominguez-Delmas, M. (2016. Shipwreck records and tree rings unveil Caribbean hurricane history – and clues to the future. The Conversation. https://theconversation.com/shipwreck-records-and-tree-rings-unveil-caribbean-hurricane-history-and-clues-to-the-future-55730
  More info

  I was invited to write a piece about our PNAS paper for the scientific outreach website The Conversation.
• Trouet, V. M. (2015. How We Discovered the Sierra Nevada Snowpack Is at a 500-Year Low. Zocalo Public Square. http://www.zocalopublicsquare.org/2015/09/22/how-we-discovered-the-sierra-nevada-snowpack-is-at-a-500-year-low/ideas/nexus/: Zocalo Public Square. http://www.zocalopublicsquare.org/2015/09/22/how-we-discovered-the-sierra-nevada-snowpack-is-at-a-500-year-low/ideas/nexus/
  More info

  We was invited to write a popular science piece for the website Zocalo Public Square. Many other news outlets have picked up what I wrote for this website.
• Trouet, V. M., & Belmecheri, S. (2015. The 2015 Sierra Nevada snowpack is at a 500-year record low. The Conversation. https://theconversation.com/the-2015-sierra-nevada-snowpack-is-at-a-500-year-record-low-47380: The Conversation. https://theconversation.com/the-2015-sierra-nevada-snowpack-is-at-a-500-year-record-low-47380
  More info

  We wrote a popular science piece for the website The Conversation.

Others

• MacDonald, G., Wall, T., Evans, M. E., Breshears, D. D., Falk, D. A., Trouet, V. M., Woodhouse, C. A., & co-authors, 1. (2021, October). A Consensus Report on Causes of California’s Changing Wildfires by Scientists of the Southwest Climate Adaptation Science Center. Southwest Climate Adaptation Center (SWCASC).