Processed global tree-ring width data and codes for "Global tree growth resilience to cold extremes following the Tambora volcanic eruption"

Although the global climate is warming, external forcing driven by explosive volcanic eruptions may still cause abrupt cooling. Herein, we investigated the magnitude of forest resilience shifts and their recovery time to the strong and lasting volcanic cooling after the 1809 and 1815 Tambora eruptions using 3304 tree-ring width chronologies across the globe. Global raw tree-ring width chronologies were collected from 3 sources, the International Tree-Ring Data Bank (ITRDB), the GenTree dendroecological collectionand the collection from the tree-ring group of the Institute of Tibetan Plateau Research, Chinese Academy of Sciences (ITPCAS). We transformed the raw tree-ring width data (RW) into ring-width indices (RWI) by removing long-term trends caused by aging and increasing trunk diameter. Since the continuous two major eruptions were recorded to have long-term effects on ecosystems, we used the most conservative standardization technique of fitting negative exponential curves to detrend tree-level series using the dplR package in R. Site-level, standard chronologies of RWI were averaged using a bi-weight robust mean. A 30-year cubic smoothing spline was also used to detrend for checking the stability of the influence time of volcanic forcing on tree growth.