Can you help us to identify this picture further?

We have a problem locating the excact source of this nice little vignette illustration. We found it in "Mytologisk Leksikon" (a Danish translation of "Knaurs Lexikon der Mythologie" by Gerhard J. Bellinger, Droemer Knauer Verlag, Munchen 1989; in Danish 1993, translated by Jørgen Hansen, published by Gyldendal).

The picture is a Siberian world picture (on p. 349 in the Danish edition, located near the entry "shaman"). The small vignette has the following figure caption (our translation to English)

"Siberian world picture in the form of a world tree, that from the underworld reaches out over the Earth with deer and humans and reaches up to the sky (see shaman)"

Alexander Eliot (1976): Myths. McGraw-Hill, New York.
ISBN 0-07-019193-X (with contributions by Mercea Eliade, Joseph Campbell; captions and graphic essays by Detlef-I. Lauf; creative design and selection of pictures by Emil Bührer):

The picture is reproduced on p. 77 with the caption:
"The world tree appears again in this drawing from a Shaman drum (above left); with its roots in the underworld it rises through the inhabited earth to penetrate the realm of the gods."
[written by A.Eliot, in the section `Cosmology' p. 77]
p. 307 [in the section Illustration credits] reads:
[p.77]: "The axis mundi. Shaman's drum. Iceland. P: Courtesy Thames and Hudson."

[Strange that this becomes a "Siberian world picture" in Mytologisk Leksikon from Knauer].

On p. 43 in Eliot's book, another very similar picture appears with the text caption "The next drawing shows the world tree/axis rising through the world of men and animals to the vault of heaven and the realm of the Great Spirit." [p. 306 in the list of illustrations: "Shaman's drum. Publisher's Archives."]

We are interested in the deeper signification of this small drawing, but also its exact source, history and further meaning, and would be very thankful if someone is able to help us.

Any suggestions are welcome!