This cache is a very simple Multi Cache and is part of my New Series of Caches called "Twelve Cache Types in a Day. I have placed one of each available cache type close together so that anyone can get upto Twelve Cache Types in a Day.
WP1: At the start point you will find a target tree. Count the number of Tree Trunks in the group
Number of Tree Trunks in the Group = A
Calculate GZ as S35 10.A08 E 149 09.509