Forest Leaf Litter Nutrient Dynamics: Persea americana

The avocado is one of the most common dooryard fruit trees for home gardens and agroforestry settings in Guam and the rest of the Mariana Islands. 

The avocado is native to Central America. Any attempts of the early Spanish galleons to introduce the tree to the Mariana Islands were unsuccessful. William Safford is credited with the first successful introduction of the tree to Guam during his 1899-1900 tenure as the Assistant Governor of Guam.

It is called alageta on Guam.

This fruit tree has two major limitations in the Mariana Islands. First, almost all trees are grown from seeds, so fruit quality traits vary from tree to tree. The photograph depicts fruits harvested from a single Yigo, Guam farm.  A commercial fruit industry cannot be built around this extreme variability. Second, almost all of the avocado trees produce fruit at the same time each year.  A single tree can be highly productive, and sometimes the fruits are so plentiful they cannot be marketed. Cultivars that produce fruits out of season are needed.

The Western Pacific Tropical Research Center introduced numerous avocado cultivars to Guam and spent years evaluating their productivity. ‘Malama’ passed all of the tests indicating the tree would flower consistently in Guam’s climate and produce fruits several months later than the bulk of Guam’s avocado trees.

Elemental composition of avocado leaf litter from five locations throughout the Mariana Islands.

Chemical and physical traits of avocado leaf litter that may influence speed of litter decomposition.

Avocado leaf litter decomposed at a relatively slow rate compared to the other tree species. About half of the litter had decomposed by four months. Most of the farm sites exhibited complete decomposition by 18 months. The farm site in northern Guam exhibited slower avocado leaf litter decomposition, reaching 100% decomposition at 32 months.