Sensitivity-Complacency

Tree growth (e.g., ring width) is described as dendrochronologically "sensitive" when it exhibits a high degree of annual variation with wide and narrow rings intermixed through time, as illustrated by the top core sample of the figure above and which is typical of many pine species growing in semi-arid environments (e.g., ponderosa pine of the North American Southwest).   This results from having a limiting factor, rainfall for example, that is highly variable from year to year.   When crossdating tree-ring specimens, dendrochronologists prefer reasonably sensitive growth patterns because matching patterns of relatively wide and narrows rings across trees is easier when ample variation exists in ring width.

Conversely, tree growth is described as dendrochronologically "complacent" when it does not exhibit a high degree of annual variation, i.e., rings are roughly the same width for many years consecutively, as illustrated by the bottom core sample of the figure above and which is typical of many tree species growing in relatively mesic environments (e.g., giant Sequoia of the Sierra Nevada of California and many species in the eastern US).   This results from not having a limiting factor (with respect to ring width, in this case) that is highly variable from year to year.   It is more difficult to crossdate complacent tree-ring specimens because matching patterns of relatively wide and narrows rings is hard when there is not much variation in ring width.

On the applet, the default sensitivity-complacency setting is very sensitive (a value of 1 on the scroll bar).   Try changing the setting all the way to very complacent (a value of 10 on the scroll bar) and then restart a new core to see the different levels of sensitivity-complacency in the randomly generated virtual tree-ring sample.   Show the master chronology to also see how the time series of relative tree growth varies when you change the sensitivity-complacency setting.   If and when you try to crossdate a complacent series, you should consider trying a longer series, i.e., one with more rings, in order to improve your likelihood of success.