<P> This is a list of the oldest known trees, as reported in reliable sources . Definitions of what constitutes an individual tree vary . In addition, tree ages are derived from a variety of sources, including documented "tree - ring" count core samples, and from estimates . For these reasons, this article presents three lists of "oldest trees," each using varying criteria . </P> <P> There are three tables of trees, which are listed by age and species . The first table includes trees for which a minimum age has been directly determined, either through counting or cross-referencing tree rings or through radiocarbon dating . Many of these trees may be even older than their listed ages, but the oldest wood in the tree has rotted away . For some old trees, so much of the centre is missing that their age cannot be directly determined . Instead, estimates are made based on the tree's size and presumed growth rate . The second table includes trees with these estimated ages . The last table lists clonal colonies in which no individual tree trunks may be remarkably old but in which the organism as a whole is thought to be very old . </P> <P> The current record - holders for individual, non-clonal trees are the Great Basin bristlecone pine trees from California and Nevada, in the United States . Through tree - ring cross-referencing, they have been shown to be more than five millennia old . </P>

What is the name of the oldest plant on earth