Tree-Ring Science (Dendrochronology)

The study of tree rings through time is the fundamental basis for dendrochronology. The principle of crossdating is what allows us to assign a calendar year to every ring that a tree grows. Once we have this information, we can use tree rings as a proxy for all kinds of historical, environmental, ecological, and archaeological inquiries. In the dendrochronology lab at USU, we have undertaken projects to crossdate virtually every species that exists in the western U.S. Furthermore, we have made serious scientific progress working with species that are not conventionally considered useful to dendrochronologists, species like Utah juniper, and curlleaf mountain mahogany. We also crossdated and analyzed tens of thousands of increment cores from the USDA, Forest Service, Forest Inventory and Analysis program all across the west. These cores are collected from plots at random and have been used to push the science of dendrochronology into the future. 

Related Literature:

M.E.K. Evans, R.J. DeRose, S. Klesse, M.P. Girardin, K.A. Heilman, M.R. Alexander, A. Arsenault, F. Babst, M. Bouchard, S.M.P. Cahoon, E.M. Campbell, M. Dietze, L. Duchesne, D.C. Frank, C.L. Giebink, A. Gómez-Guerrero, G.G. García, E.H. Hogg, J. Metsaranta, C. Ols, S.A. Rayback, A. Reid, M. Ricker, P.G. Schaberg, J.D. Shaw, P.F. Sullivan, and S.A.V. GaytÁn. 2022. Adding tree rings to North America’s national forest inventories: an essential l tool to guide drawdown of atmospheric CO2. BioScience 72(3):233-246. (link)

Klesse, S., R.J. DeRose, C.H. Guiterman, A.M. Lynch, C.D. O’Connor, J.D. Shaw, and M.E.K. Evans. 2018. Sampling bias overestimates climate change impacts on forest growth in the southwestern United States. Nature Communications 9:5336. (link)

DeRose, R.J., J.D. Shaw, and J.N. Long. 2017. Building the Forest Inventory and Analysis tree-ring data set. Journal of Forestry 115:283-291. (link)

DeRose, R.J., M.F. Bekker, R. Kjelgren, B.M. Buckley, and E.B. Allen. 2016. Dendrochronology of Utah juniper (Juniperus osteosperma (Torr.) Little). Tree-Ring Research 72:1-14. (link)

Dendroclimatology

One of the most common uses of tree rings is to reconstruct past climates. When we reconstruct climate, we choose trees from specific sites where they record the climate variable we are interested in faithfully, year after year. We can statistically determine what factor the trees are responding to and check for fidelity across time using historical climate data. Only when these tests have been passed do we build reconstruction models that extend back in time many centuries to millennia. In our lab, we have collected, crossdated, and analyzed multiple species of trees that have strong hydroclimatic records. Species like Douglas-fir, ponderosa pine, and Utah juniper, among others, have been used to build reconstruction models of precipitation, drought, and stream flow. The reconstruction time-series allows us to infer environmental conditions in the distant past that may be unlike anything we have witnessed in the historical record. For example, a stream flow reconstruction of the Bear River in northern Utah revealed an unprecedented megadrought that started in the 11th century. This drought lasted for more than 70 years at below average flow conditions. 

Related Literature:

Birch, J. D., R.J. DeRose, and J. A. Lutz. 2024. Spruce up your climate analysis: Dendroclimatology of Picea engelmannii and Picea pungens. Ecosphere 15:e70047. (link)

DeRose, R.J., M.F. Bekker, S.-Y. Wang, B.M. Buckley, R. Kjelgren, T.J. Bardsley, T.M. Rittenour, and E.B. Allen. 2015. A millennium-length reconstruction of Bear River stream flow, Utah. Journal of Hydrology 529:524-534. (link)

DeRose, R.J., S.-Y. Wang, B.M. Buckley, and M.F. Bekker. 2014. Tree-ring reconstruction of the level of Great Salt Lake, USA. The Holocene 24:805-813. (link)

Dendroecology

An important area of research using tree rings is in the investigation of ecological processes that have been recorded over time in tree growth. In our lab we have pioneered the use of tree rings for a myriad projects that are unconventional by traditional dendrochronological standards. Exploring tree rings that record beetle outbreak activity, frost damage, patterns of growth reduction over time, and determining dates of tree death to the year using the waney edge are all techniques we employ. We also have pioneered the use of randomly collected tree-ring samples for widescale network analyses of growth and climate response - an approach that more directly measures the population level response of species. In another example, the associated picture shows the resin ducts produced during xylogensis by Engelmann spruce trees that have successfully responded to infesting bark beetles, pitching them out, warding off a mass-attack that might occur during a beetle outbreak. 

Related Literature:

Birch, J.D., Y. Chikamoto, R.J. DeRose, V. Manvailer, E.H. Hogg, J. Karst, D.M. Love, and J.A. Lutz. 2023. Frost-associated defoliation in Populus tremuloides causes repeated growth reductions over 185 years. Ecosystems 1-17. (link)

Blomdahl, E.M., J.H. Speer, M. Kaye, N.E. Zampieri, M. Rochner, B. Currey, D. Alving, G. Cahalan, B. Hagedorn, H. Li, R. Oelkers, L. Pelletier, I. Thapa, K. Willson, B.D. Woodward, and R.J. DeRose. 2022. Drivers of vegetation change in high elevation forests of the Greater Yellowstone Ecosystem. Journal of Vegetation Science 33:1-14. (link)

Klesse, S., R.J. DeRose, F. Babst, B.A. Black, L.D.L. Anderegg, J. Axelson, A. Ettinger, H. Griesbauer, C. Guiterman, J. Harvey, Y.-H. Lo, A. Lynch, C. O'Connor, C. Restaino, D. Sauchyn, J.D. Shaw, D.J. Smith, L. Wood, J. Villenueva-Diaz, and M.E.K. Evans. 2020. Continental-scale tree-ring-based projection of Douglas-fir growth: Testing the limits of space-for-time substitution. Global Change Biology 26(9):5146-5163. (link)

DeRose, R.J., M.F. Bekker, and J.N. Long. 2017. Traumatic resin ducts as indicators of bark beetle outbreaks. Canadian Journal of Forest Research 47:1168-1174. (link)

Dendroarchaeology

The field of dendrochronology got its start crossdating archaeological material in the southwest U.S. The use of tree rings for archaeological purposes has grown since then. In our lab, we have focused on extending tree-ring proxies back in time over two thousand years in order to develop environmental records that overlap with the Fremont - ancient people who lived in Utah over 800 years ago. By carefully selecting species and sites, we have been able to develop environmental records of drought, precipitation, and high/low stream flow events that may have contributed to agricultural production or abandonment. In addition to confirming the major drought during the Medieval Climate Anomaly in the 11th and 12th century, our extra-long tree-ring reconstructions have detailed even worse drought conditions nearly two thousand years ago during the 1^st and 2^nd century AD. Ongoing research is linking the tree-ring record with carbon-dated artifacts from archaeological dwellings across the Great Basin and Colorado Plateaus and is revealing the nuance in ancient people's lifeways. 

Related Literature: 

Finley, J.B., E. Robinson, and R.J. DeRose. 2023. Arroyo formation impacts on an early dryland agricultural community in northeastern Utah, USA. Geoarchaeology 38(1):109-126. (link)

Carter, V.A., A. Brunelle, M.J. Power, R.J. DeRose, M.F. Bekker, I. Hart, S. Brewer, J. Spangler, E. Robinson, M.B. Abbott, S.Y. Maezumi, and B.F. Codding. 2021. Legacies of Indigenous land use shaped past wildfire regimes in the Basin-Plateau Region, USA. Nature: Communications Earth and Environment 2(1):1-19. (link)

Finley, J.B, E. Robinson, R.J. DeRose, E. Hora-Cook. 2020. Multidecadal climate variability and the fluorescence of Fremont societies in Eastern Utah. American Antiquity 85(1):93-112. (link)