A recent article (Lawler, 1980) mentioned a common misunderstanding in archaeological circles which this note attempts to correct: ‘The (Runnymede) piles selected will be subjected to destructive testing (i.e. dendrochronology) to gain information concerning growth patterns, habitat and tree-felling patterns…’ In fact, dendrochronology is not a destructive dating method in the sense of radiocarbon analysis, where the wood sample is burnt up and completely lost. Instead, the section removed for tree-ring analysis remains undamaged and can easily be restored to the beam or pile for conservation without any detriment to the timber's display potential.