Tex. Nat. Res. Code § 151.001

Before purchasing or accepting delivery of any trees, timber, logs, pulpwood, or in-woods chips, a seller shall provide and a purchaser shall require a bill of sale for the trees, timber, logs, pulpwood, or in-woods chips executed by the seller. The bill of sale may be a part of, a compilation of information taken from, or an addendum to, by way of example, a timber deed, scale ticket, weight ticket, cutting contract, harvest agreement, wood purchase agreement, or other records of the sale and purchase made at the time if all the information required by Section 151.002 is included.