Sensitivity-Complacency

"Sensitive" tree growth: High degree of annual variation Example: wide and narrow rings intermixed through time Typical of many pine species growing in semi-arid environments Example: ponderosa pine of the North American Southwest Limiting growth factor (e.g., rainfall) is highly variable year to year Especially true for harsh (steep, rocky) sites Reasonably sensitive ring growth is good: Matching patterns of relatively wide and narrows rings across trees is easier when ample variation exists

"Complacent" tree growth: Low degree of annual variation Example: rings are roughly the same for many years consecutively Typical of many tree species growing in relatively mesic environments Example: Giant Sequoia of the Sierra Nevada of California and many species in the eastern US limiting growth factor is not variable from year to year Especially true for benign (flat, deep soil) sites Complacent ring growth can be difficult to crossdate: matching patterns of relatively wide and narrows rings is hard when not much variation exists