This oak tree is amazing! It's definitely worth checking out if you are in the area. The story behind it's odd shape is quite interesting. I'll leave it to you to discover that!
Cache is not at the posted coordinates. To uncover the final coordinates, you will have to come to the location and gather information from two sources, one of which you will need a special tool to get access to the information, the other can be obtained from the information provided on one of the plaques at the posted coordinates.
The cache is located at:
N 029 42.ABC W 098 08.DEF
ABC - Subtract 1139 from the year the Citizens of New Braunfels started to annually gather under this magnificent tree on July Fourth to read the Declaration of Independence and to dedicate themselves to the principles for which it stands.
DEF - Subtract 1700 from the year Joseph Landa, a German merchant and industrialist, purchased the nearby springs and river area (look on the Founder's Oak plaque).