Question

why are tropical deciduous forest also called monsoon forest?

Answer 1

Because of open woodland and a long dry weather followed by a heavy rain session next.

Answer 2

The tropical deciduous forests are also called monsoon forest because the trees in these forests shed their leaves during dry season and re-grow during monsoon.

These forests witness a long dry season and during this period the trees in these forests shed their leaves. The dry season is followed by heavy rainfall or monsoon and the trees re-grow their leaves. So they are called dry forests as well as monsoon forests.