P van Rijckevorsel wrote:
PS Once upon a time there were also believed to be poisonous trees that
could be recognized by the dead birds accumulating under it (they tried
to fly over the tree but were smitten with the poison)

Beverly Erlebacher schreef
That may be the semi-mythical Upas tree, the poisonous exhalations of
which killed everything for miles around.

+ + +
That is what I was referring to
+ + +

You aren't supposed to ask
how people knew there was a tree in the middle of this dead zone. I
say "semi-mythical" because upas is also associated with a real tree,
Antiaris toxicaria, the sap of which is used to make an arrow poison.

I googled on "upas tree" and found among other things a poem by Pushkin,
which I hope is less florid in Russian than in English at

http://ruslit.virtualave.net/pushkin/upasengl.html

As well as this account at http://www.bartleby.com/81/16994.html
[snip] This fable is chiefly due to Foersch, a Dutch physician, who
published his narrative in 1783.

Being Dutch I confess to never having heard of this Foersch [Försch ?], in
this country the story is attributed to the famous Rumphius, likely as in

http://www.selectbooks.com.sg/titles/3102.htm

PvR