【Area】 , 【tract】 , 【region】 , 【zone】 , and 【belt】 mean an extent of space especially of ground or surface that is distinguishable from its surroundings in appearance or in certain distinctive features.

【Area】 still carries its original implication of clearly marked bounds, but it may be used with reference to a space defined on a map or chart as well as to one the limits of which are actually visible.

• an oasis is a green or fertile 【area】 in a desert
• there are vast uncultivated areas even in the most populous of the states
• two colors—aspen and evergreen, not intermingled but lying in solid areas of light and dark
  —Gather

【Tract】 , on the other hand, stresses extent rather than limits; it is therefore preferred to 【area】 in designating a space that might otherwise be described as an expanse or is thought of as widespread or far stretching and uniform in character.

• beyond the 【area】 of small farms lay larger tracts that were immensely productive
  —Anderson
• a 【tract】 of grass, furze and rushes, stretching away to the western horizon
  —Shaw

【Tract】 is often used in an extended sense in reference to anything that has extent or duration.

• wide tracts of life—Day Lewis} <a large 【tract】 of unwritten history
  —S. Eliot

【Region】 suggests reference to some definite place or locality (as on the earth′s surface, in the atmosphere, or in the human body) distinguished from other localities by certain features or by being subject to a particular condition or influence.

• the upper 【region】 of the air
• the Finger Lakes 【region】 of central New York State
• what 【region】 of the brain is the seat of consciousness?

【Zone】 denotes an 【area】 or 【region】 that suggests a girdle or an encircling band especially on a map or chart.

• the torrid, arctic, and temperate zones
• parcel post zones
• the pelagic 【zone】 of the ocean

In broader use it is often applied to an 【area】 that forms a band or strip and is distinctly set off from its environs by some peculiarity of feature.

• the firing 【zone】 of a battlefield
• the business zones of a city
• that milky way which nightly as a circling 【zone】 thou seest powdered with stars
  —Milton

Basically 【belt】 is a synonym of 【zone】 ; distinctively, it implies an 【area】 characterized by the presence of some distinguishing natural feature (as a particular flora or mineral).

• the corn 【belt】 of the U.S.
• a coal 【belt】 } In strict technical usage 【belt】 is applied to an 【area】 less extensive than a 【zone】 .
• a 【belt】 of conifers extending into the northern mixed forest 【zone】