<p dir="ltr">Heart rot is considered to be an important source of error in forest carbon accounting, especially in old-growth forests dominated by large trees. However, the relationship between heart rot and carbon sinks has not been sufficiently studied. Here, we provide a dataset to study this issue using Korean pine (<i>Pinus koraiensis</i> Sieb. et Zucc.), a dominant tree species in typical temperate old-growth forests, as an example.</p>