Poem: In spring, buds grow on trees. Trees in summer are covered with thick leaves. Trees in autumn are covered with bright red and golden leaves. Under the trees in winter, leaves fall to the ground and become soil. Fallen leaves are the imprint of nature. Give it to you, give it to me, and give it to everyone all year round.

Extended data:

A series of nature protection stamps issued by the World Wide Fund for Nature (WWF), starting from 1983, were jointly issued by WWF and the Swiss philatelic agency Groth AG.

The principle of issuing these stamps is that only those endangered animals in the issuing country can be used as the theme of stamps. We only allow countries from 16 to 18 to issue stamps with the logo of WWF every year, so as not to issue too many stamps. We encourage the choice of lower face value to avoid speculation.

"WWF's thematic stamp collection series provides an excellent opportunity for stamp collectors and people who care about protecting the natural environment, and also makes a direct contribution to the protection of nature." Prince Philip, Duke of Edinburgh and Honorary President of WWF.