| The relationship between environmental variables and the oxygen isotope composition of alpha-cellulose in ringed tropical trees may not be constrained to simple "amount effects." Here I present a 55-year continuous record of delta18O of alpha-cellulose from Pinus kesiya. By comparing the cellulose isotope record to previous data, model theory, and rain amount data it is clear that both amount effects as well as isotopic changes in atmospheric circulation regimes are incorporated in the oxygen isotopic ratio of the alpha cellulose. Regression analysis show most of the variability recorded in the delta18O of cellulose results from changes in total annual rainfall, and large anomalies arise during La Nina and El Nino events. A proxy rainfall reconstruction exhibits poor correlation with rainfall variability and will require further work in order to constrain how best to extract a quantitative estimate of rainfall. |
PDF Full Text Request