The Burr Oak in the picture in this post was part of a dendrochronological analysis project and was found to have been a seedling in 1855.

So, how do certain trees live so long?

Trees live thousands of years because they are mostly dead tissue, can replace lost limbs, and never stop growing. A massive old tree is up to 95% dead wood, meaning it requires very little energy to survive. They also use stem-cell-like meristem tissues to continuously repair themselves, dodging the cellular aging that limits animals.

Trees that live long lives have resources such as adequate soil, nutrients, water, and other factors that enable them to produce sufficient energy (carbohydrates).

Modular Growth: Animals have a fixed body plan, but trees grow like modular Lego sets. If a branch is damaged or a root is severed, the tree simply seals the wound and forms a new one, thereby isolating the disease.

Stem Cells: Instead of aging like human cells, a tree's meristematic cells—located just beneath the bark—divide indefinitely to create new rings of wood and vascular tissue every year.

Dead Support Systems: The bulk of a tree’s trunk (the heartwood) is entirely dead wood. It provides necessary structural support against storms and gravity without requiring nutrients or oxygen to survive.

Chemical Defenses: Ancient trees are highly adapted to produce resins and tannins that naturally repel wood-boring insects, rot, and fungi.

Slow Metabolism: The oldest trees, like the 5,000-year-old Bristlecone Pines in California, grow incredibly slowly in harsh, high-elevation climates. This deliberate pace prevents them from exhausting their resources.

Often, when these same principles are applied to tree management in the urban landscape, the tree in question can live a longer, more productive life.