With over 500 species, oaks (Quercus spp.) have a range of lifespans. Under ideal conditions, oak trees live an average of 150 years, with short-lived varieties lasting 50 to 60 years and long-lived varieties living more than 150 years. Unfortunately, poor environmental conditions, pests, diseases and commercial development all affect how long an oak tree lives.
Species that Live Longest
Many oak trees live longer than 150 years, although few reach the age of one southern live oak (Quercus virginiana) in Louisiana, which American Forests, a conservation organization, estimated to be 1,500 years old. Besides southern live oak, large and long-lived oak varieties include holly oak (Quercus ilex), which like southern like oak is hardy in U.S. Department of Agriculture plant hardiness zones 7 through 10, canyon live oak (Quercus chrysolepis, USDA zones 8 through 10) and valley oak (Quercus lobata, USDA zones 7 through 9).
Varieties that Live a Short Time
For oak trees, 50 years counts as short-lived. A native of the southeastern United States, laurel oak (Quercus laurifolia) lives 50 to 60 years and grows to about 65 feet tall. Also native to the Southeast, water oak (Quercus nigra) reaches 60 to 80 feet tall and lives 30 to 50 years. Laurel oak and water oak are hardy in USDA zones 6 through 10.
Factors that Increase Lifespan
Planting an oak tree that thrives in your USDA zone helps to ensure that the tree has the best chance of living a long and healthy life. All oak species grow best in sites with full-sun exposure, but different varieties have different watering needs. Oaks from dry-summer areas, such as valley oak, need no watering during winter after they've been in their location for six or seven years while species native to wet climates, such as water oak, require watering during winter.
Factors that Limit Lifespan
Compacted soil, changes to your yard's grade or overwatering can kill your oak tree. The oak may take close to 10 years before succumbing to such pressures, but it will begin to decline, and you may not be able to save it once you notice its thinning canopy or dying leaves. If your oak bleeds sap that has a strong odor, then the tree may be infected with the disease called sudden oak death, which may kill the tree within weeks or two years. The disease is incurable and can spread to other susceptible plants if you don't remove the affected tree from your yard.