Dozens of stamp collections, postcards and postal objects by 30 private collectors are on display at an exhibition titled For a Green Colour in downtown HCM City .

The collections cover a wide range of topics, from Hue and farming to wildlife.

The exhibition, the fifth of its kind in Vietnam , responds to the United Nations' International Year of Forests and is among a series of environmental preservation activities in the country.

It will run until Nov. 27./.