Definitions of longevity vary between clonal trees, ones where parts of the tree continue to live after the death of the first trunk or trunks, and non-clonal trees. Tree ages are derived from a variety of sources, including documented "tree-ring" (dendrochronological) count core samples, radiocarbon dating, girth-to-age formulas, and estimates from growth rates. For these reasons, there are three lists of "oldest trees" here, using different criteria.

The three tables of trees are listed by age and species. The first table describes 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 center 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.

The 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 almost five thousand years old.

A clonal colony can survive for much longer than an individual tree. A colony of 48,000 quaking aspen trees (nicknamed Pando), covering in the Fishlake National Forest of Utah, is considered one of the oldest and largest organisms in the world. Recent estimates set the colony's age at about 16,000 to 37,000 years, although tree ring samples date individual stems at rarely more than 130 years. A colony of Huon pine trees covering on Mount Read (Tasmania) is estimated to be around 10,000 years old, as determined by DNA samples taken from pollen collected from the sediment of a nearby lake. Individual trees in this group date to no more than 4,000 years old, as determined by tree ring samples.

Non-clonal trees with ages from cross-dating

Cross-dating via dendrochronology is the most exact method for dating a wood sample. Cross-dating is the method of finding the age of a tree ring by matching growth patterns across multiple trees from the same location. Cross-dating can date a wood sample to a precision of one year.

This list contains tree ages determined from dendrochronological cross-dating. It has all trees with ages more than 2000 years, and a sample of notable trees (one per species) younger than that. If cross-dating has not been reproducible (e.g., because a tree core has become missing), the unreproduced age is listed in the section below. If there are multiple ages (e.g., due to inconsistency in tree cores or lack of reproducibility), the lowest verified age is shown here, and the highest is shown in the estimated table, below.

Non-clonal trees with estimated ages

Note: The ages of the trees in this list are estimated via methods that are less accurate than cross-dating. Some of the ages are based on tree size, which is known to have 20% error. Ages in this table should be treated as speculative.

Clonal trees

As with all long-lived plant and fungal species, no individual part of a clonal colony is alive (in the sense of active metabolism) for more than a very small fraction of the life of the entire clone. Some clonal colonies may be fully connected via their root systems, while most are not actually interconnected, but are genetically identical clones which populated an area through vegetative reproduction. Ages for clonal colonies, often based on current growth rates, are estimates.

See also

• King Clone

• List of individual trees

• List of largest giant sequoias

• List of longest-living organisms

• List of old-growth forests

• List of superlative trees

• Oldest viable seed

• Veteran tree

Notes

References

Sources

1. Books