Comparison of cellulose 14C of the growth rings 1962–1965 of Norwegian Scots pine with Norwegian atmospheric 14CO2 over these bomb spike years indicates that tree rings can provide a good proxy for atmospheric 14CO2. The sub-seasonal cellulose 14C values of five trees from 63° to 69° N reveal local atmospheric 14CO2 values for the growing seasons 1950–1965. The 1950s are of special importance because there exist few direct measurements of atmospheric 14CO2 during this period of active atmospheric nuclear testing. First indications of bomb 14C are seen already in 1952. The temporary halt of atmospheric testing from November 1958 to September 1961 led to a temporary maximum in atmospheric 14C concentrations in 1959, creating the 1950s atmospheric bomb-14C peak. Longer atmospheric travel of 14C from low-latitude and Southern Hemisphere tests to Norway led to the highest tree 14C values in 1959 and 1963/’64 after testing stopped, respectively, in 1958 and 1962. The Scots pine data demonstrate that local atmospheric 14CO2 records with sub-annual resolution can generally be obtained. Combination with the SIPRI data base of nuclear testing, allows a focus on the production of bomb 14C and its transport through the atmosphere to the tree and promises a better understanding of the atmospheric mixing of CO2. Together with high-resolution local 14CO2 records this can better define the exchange between the atmosphere and the other reservoirs of the carbon cycle during the period of isotopic disequilibrium caused by atmospheric nuclear testing.