Each person operating a creosoting or other preservative treatment plant, where crossties, crossarms, poles, posts, or other lumber or timbers are creosoted or treated shall pay a license tax based on the capital invested in such plant for equipment, raw materials, finished materials, supplies, realty, and all personalty, as follows: Where the capital invested is less than $5,000, $20 for the state and $10 for the county; where the capital invested is $5,000 and less than $25,000, $50 for the state and $25 for the county; where the capital invested is $25,000 and less than $50,000, $75 for the state and $37.50 for the county; where the capital invested is $50,000 or over, $100 for the state and $50 for the county.