Estimated to be over 500 years old, the large oak tree standing on a busy urban street corner is a local symbol of Texas history, and a international symbol of resilience. It is the last of fourteen Live Oak trees once known to Comanche and Tonkowa Indians as the Council Oaks where both peace and war parties were initiated. Religious ceremonies were held where a tea was made from its acorns in hopes of protecting loved ones far from home. Legend also tells that Stephen Austin himself signed the first treaty between the Anglos and the Indians beneath the shade of this tree in 1824, thus the tree’s name.

The majestic tree’s wide canopy stretched 127 feet in diameter and bore witness to countless naps, picnics, feasts, proposals, marriages, and religious and educational services. Sam Houston is even said to have rested beneath its limbs after his expulsion from the governor's office at the dawn of the civil war. In 1922, the American Forestry Association named the Treaty Oak as the most perfect specimen of any living tree in the country; its picture hangs in their hall of fame in Washington, D.C. In 1937, in an effort to protect the land and tree from development, the city of Austin bought the land and turned it into a park.

In 1989, calls began to come in to the city forester that brown spots were appearing beneath the tree and that some of its leaves were beginning to fall off. First thought to be diseased, lab results soon showed that the tree had been exposed to a poison called Velpar in an amount capable of killing 100 trees! Experts from all over the state lent their hands to save the tree. Newspapers and media outlets worldwide covered the story of "who would poison a tree?" Billionaire Ross Perot helped fund the rescue and DuPont, the company which produces Velpar, staked a $10,000 reward for the capture of the poisoner. Flowers, candles, crystals, and get-well cards were piled at the foot of the tree and psychics measured and shared its energy.