treeclim: an R package for the numerical calibration of proxy‐climate relationships

The R package treeclim helps perform numerical calibration of proxy‐climate relationships, with an emphasis on tree‐ring chronologies. The package provides a unified, fast, and public‐domain compilation of established methods while adding novel functionality not implemented in other software. treeclim includes static and moving bootstrapped response and correlation functions, seasonal correlation analysis, a test for spurious temporal changes in proxy‐climate relations, and the evaluation of reconstruction skills. The stationary bootstrap method has been incorporated into the program as a ‘blocks of blocks’ resampling scheme. Applications of treeclim include the calibration of proxy timeseries used in paleoclimatology, forest ecology, and environmental monitoring.