Largest of the three 13th-century candidates, 1268 to 1269 (Miyahara 2022)

Miyahara 2022: 1267 -16.93, 1268 -16.48, 1269 -11.97, 1270 -11.55 permil. A 4.5 permil jump into 1269, the largest of the three, about 27 percent of the 774 event. Brehm's Swiss tree shows the step one ring later, into 1270, as an oak-like lag would. Timing rule from Miyahara et al. 2022: their asunaro (a Japanese conifer) photosynthesises from April and builds each ring mainly from April to August carbon of the same year. So a jump between ring N and ring N+1 means the burst of carbon-14 arrived after about August of year N and before about mid-year N+1. Oaks, by contrast, build their spring wood from the previous year's stored sugar, so oak records can lag a year.