[Discrimination against New Mexico softwood timber in

building codes prohibited.] It shall be unlawful for any building code or codes of this state or of any county, municipality or township therein, or of any agency, bureau or political division or subdivision of the state government to discriminate in any way against the softwood species of timber, such as Douglas fir and ponderosa pine, grown in New Mexico. All the various grades of lumber produced therefrom, and the softwood species of New Mexico lumber shall be considered, regarded and accepted prima facie as the equal in strength and durability of similar softwood species produced elsewhere, and the burden shall rest upon any person contesting this provision to prove to the contrary in a court of competent jurisdiction by a preponderance of the evidence.