A tree-ring chronology is a time-series of annual values derived from the ring-width measurements of 10 or more trees of the same species at a single site. Chronologies are the building blocks for reconstructions of streamflow and other hydroclimatic variables. Nearly 100 tree-ring chronologies, all more than 250 years long, have been collected from moisture-sensitive tree species across California, Nevada, and far southern Oregon and archived in the International Tree-Ring Data Bank (ITRDB) as of 2007. (A number of chronologies in the region have been collected since then, and not all collected chronologies are archived in the ITRDB.)

These chronologies have been used to help generate several hydrologic reconstructions in California, and they could be used to generate new reconstructions in other California basins. Note that a chronology doesn't need to be in a particular river basin in order to capture the regional flows of atmospheric moisture that drive streamflow in that basin. If you are interested in a streamflow or other hydroclimatic reconstruction for your basin(s) of interest, please contact Connie Woodhouse.

In the map below, the locations of tree-ring chronologies are shown by green triangles. The numbers next to the chronologies correspond to additional information in a table below the map. The ring-width data for each chronology can be accessed by using the search form for the ITRDB and entering the Site Name.

Species Codes:

JUOC - Juniperus occidentalis (Western juniper)

PIAL - Pinus albicaulis (whitebark pine)

PIBA - Pinus balfouriana (foxtail pine)

PIJE - Pinus jeffreyii (Jeffrey pine)

PILO - Pinus longaeva (Great Basin bristlecone pine)

PIMO - Pinus monticola (singleleaf pinyon)

PIPO - Pinus ponderosa (ponderosa pine)

PITO - Pinus torreya (Torrey pine)

PSMA - Pseudotsuga macrocarpa (bigcone Douglas-fir)

QUDG - Quercus douglasii (blue oak)

QULO - Quercus lobata (live oak)