See the forests for the trees.
How and why these forest types differ.

All of the islands fall in the tropical zone, but West Indian vegetation technically is classified as neo-tropical, meaning it grows in the New World tropical zone.

(Pan-tropical refers to species found in tropical zones throughout the world; paleo-tropical to species confined exclusively to the Old World.)

  On most islands the growing conditions seem ideal. Temperatures vary little regardless of season. In summer, it's often hotter in New York than the Caribbean, where it rarely goes above 90 degrees.   

Like the temperature, the length of days and nights are a constant. Each lasts about 12 hours throughout the year.

Seasonal rainfall can vary dramatically.

However, it's not the amount of rain an area receives but whether it falls consistently and in enough quantity over all 12 months that determines whether the vegetation is that of a true rain forest or that of a humid green forest or a dry forest.

The rain forest

The cloud forest/elfin woodland

Humid green & dry forests

The coastal mangrove jungle