Question

Thorn forests are found in desert region. Give reason

Answer 1

because thorn are growing over dry areas and desert are dry areas and having less water

Answer 2

Plants which grow in forests have certain modifications in their parts respectively

long roots penetrating deep into the soil in order to get moisture.
The stems are succulent to conserve water
Leaves are modified into spines (thorns) and are small to minimize transpiration.

Hence thorn forests are seen in desert regions only ...