A special mahogany log. Mahogany trees can make a nice amount of money due to the logs being 583 coins and the planks 2,031 coins each, and two Special mahogany logs are gained at an average of 1 per 50 logs cut.The cost to make Mahogany planks is 1500 coins per log without the special logs. special mahogany log. Mahogany trees can make a nice amount of money due to the logs being 583 coins and the planks 2,031 coins each, and two Special mahogany logs are gained at an average of 1 per 50 logs cut.