Extended Data Fig. 4. Raw ring widths increase across all ages during the warmest three decades of July temperatures recorded in Kotzebue, AK.

a Twenty-one of 140 total tree cores of colonists of all ages selected for inclusion of pith. Of all 140 cores 71% included the pith or were within an estimated five years of the pith. Most cores show accelerating growth over the most recent 30 years. b All 140 cores ranked by number of rings. Raw wing width on vertical and Gregorian year on horizontal axis.