Book: Moles that build a raft, Tree that digs deeper than its friends

Question

I'm trying to find a book I read when I was young, roughly 25 years ago. I read it in German, which might complicate things, since sadly I don't know whether German was its original language or whether it was new when I read it.

The book contained multiple stories. The main story featured moles that had to go on a journey; at one point they built a raft to travel on a river.

Another story featured a tree (a weeping willow) and its friends. In a period of drought, the willow dug deeper than its friends and found a reservoir of water, but none of its friends believed it; in fact, they bullied it until they died of the drought. Later, new seeds appear and the new trees actually believe the willow.

Answer 1

I found the book: it's called Die drei kleinen Eulen und sieben andere Geschichten ("The Three Little Owls and seven other stories") by Erwin Moser.

It is actually a German book from 1989 - and yes, the title has nothing to do with the stories I remembered, but the chapter list shows that the stories are in there:

1. Die klugen Maulwürfe (← the smart moles)
2. Die Reise
3. Der Fuchs
4. König Luchs
5. Das Glühwürmchen und das Marienkäferchen
6. Der alte Iltis
7. Der Floh
8. Die Abenteuer einer Wolke
9. Die drei kleinen Eulen
10. Die glückliche Trauerweide (← the happy weeping willow)
11. Die Spitzmaus und der Pfirsichbaum