Why is Leatherwood honey so rare?

The Leatherwood tree is an understory rainforest tree and can only be found in the ancient cool-climate rainforests of Tasmania.  The nectar yield (and amount of honey that can be produced) from the Leatherwood flower is correlated to the age of the tree.  According to research conducted by the Forest Industry Council, trees under 75 years of age generally don't flower and the most prolific flowering trees are those between 175 and 210 years old.