The Pecan treee (Carya illinoensis) was designated the official state tree of Texas in 1919 (and the pecan was adopted as the state health nut in 2001). Fossil remains found in Texas show that our native pecan tree was here long before humans came on the scene. Remarkably long lived, the pecan can survive more than a thousand years and grow over 100 feet tall.

Many American Indians relied on pecans as an important food staple; they gathered wild pecans and combined them with fruits and vegetables (including beans, corn, and squashes), created an energy drink with pecan milk, used ground pecan meal to thicken meat stews, and included roasted pecans as part of their travel supplies to sustain them along the journey when food was scarce.

Besides producing the delicious pecan nut, pecan wood is used in agricultural implements, baseball bats, hammer handles, furniture, wall paneling, flooring, carvings, and firewood. The Pecan tree was designated the state tree of Texas in 1919.

Source:

Pecan History, Folklore, & more: Vegetarians in Paradise
Nutty Facts: National Pecan Shellers Association
Pecan History: The Bragg Pecan Store
Budding Pecan Tree Growers-Native American Crop: USDA

Links:

Pecan: Texas State Health Nut
State Trees - 50 States List
American Food and Agricultural Symbols