Trees in the U.S. vs Jakarta

From what I observed, the trees in the U.S. look more thin, lighter green, and yellowish in summer. The trees in Jakarta are generally thicker, bigger, and greener.

This is because of multiple reasons, like evolutionary adaptation, sunlight intensity, and humidity. In Jakarta, the trees receive more intense sunlight that the leaves produce high concentration of chlorophyll a and b combined to protect plant cells. Temperate trees (oak, birch, maple) in the U.S. generally have thinner leave because they produce lower density of chlorophyll.

The leaves in Jakarta also fully hydrated, plump, and lush due to high humidity (70%-85%) level.