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Excursions in the carbon-14 record measured in tree rings are attributed tovarious high energy but short-lived cosmic effects. So far, rapid changes at774-775 CE, 993-994 CE and 660 BCE have been convincingly interpreted as due torapid changes in solar cosmic-ray flux, usually accredited with reproduction ofthe events in trees at different locations and different laboratories, andfollowed with equivalent peaks of other cosmogenic isotopes in polar ice cores.In 2017, Wang et al. proposed a new event at 3372-3371 BCE based on a singleset of annual 14C data measured on a floating series of tree rings sampled froma buried specimen of Chinese wingnut tree (Pterocarya stenoptera). We attemptedto reproduce this event in tree rings of an absolutely dated bristlecone pinespecimen (Pinus longaeva) from the White Mountains, California USA and asubfossil European oak (Quercus sp.) from the Moselle River Valley in France.Unfortunately, we are unable to determine whether there is any rapid 14Cexcursion during this time, although the regular 11-year Schwabe cycle isclearly observable. Therefore, the presence of a cosmic-ray event as suggestedat 3372-3371 BCE cannot be confirmed. It is possible the exposed 14C spikeoccurred at some other time, the absolute age of which we cannot determineunless the precise calendar age of the Chinese wingnut wood is properlycrossdated, although the other data of Wang et al. (2017) is not inconsistentwith our records. In either case, this is important because the frequency ofsuch extreme cosmic events needs to be well-documented to assess the likelihoodof similar high-energy effects occurring in the future.

Rapid 14C excursion at 3372-3371 BCE not observed at two different locations, a comment on Wang et al. (2017)