One of the most poetic of Gaston Bachelard's writings is The Aerial Tree, a chapter in Air and Dreams: An Essay on the Imagination of Movement (originally L'Air et les songes 1943). Lyrically laced with passages from Rilke, D H Lawrence, and underscored with Bachelard's eloquent observations, the chapter limns a kind of arborimorphism, a treeness in things aerial... "Trees have such diverse shapes! they have so many and different kinds of branches! The unity of their being will seem therefore all the more striking, as is their unity of motion and their bearing."
Freely associating, The Aerial Tree at first suggested to me 'aerial' as a noun rather than an adjective: a Tree of Aerials, perhaps something like Ilya Kabakov's installation in Munster, Germany, Looking Up, Reading the Words, (1997). Designed so that one might lie back on the grass and stare up through the aerial at the sky, lines of text are delicately etched between the 'branches.'

The text of the aerial-like structure reads:
Mein Lieber! Du liegst im Gras, den Kopf im Nacken, um Dich herum keine Menschenseele, Du hörst nur den Wind und Schaust hinauf in den offene Himmel - in das Blau dort oben, wo die Wolken ziehen - , das ist vielleicht das Schönste, was Du im Leben getan und gesehen hast.
My dear friend! You are lying in the grass, with your head thrown back, not a living soul is around, you hear only the wind and look up to the open sky - into the blue, where the clouds float by - perhaps this is the most beautiful thing you have done and seen in your life.[1]
Reminscent of Alexander Rodchenko's Shukov Tower, the installation is an expression that nature and technology are not mutually exclusive. There is a further link to Rodchenko's photograph of Pines, and "via cultural memory, this image of nature blends into Kabakov's installation."[2]
Alexander Rodchenko, Guard, Shukov Tower, (1927)
Seibold-Bultmann suggests yet another layer which the Kabakov installation links to - a passage by Goethe in The Sorrows of Young Werther (1774/87): "Lying in the grass near a stream where only a few rays of sunlight penetrate the darkness of a forest, he observes insect life, and is then prompted to feel the presence of the Almighty, who ... in a state of continuous bliss bears and sustains us - then, my friend, when ... the world around me and the sky fully rest within my soul like the figure of a beloved; then I ... often think: oh if only I could express it all on paper, everything that lives so richly and so warmly within me, in such a way that it would reflect my soul, just as my soul is the mirror image of the infinite God! - My friend - but it makes me perish, I succumb to the violence of the splendour of these images."[3]
This in turn connects to the ‘epiphanic sky' - a portal to the Sublime - and Goethe's Sturm und Drang, with self intimately reconnected to the cosmos. "The possibility of epiphany through nature is bound up with a memory of the unfragmented Romantic self [...] Epiphany can be, but does not have to be experienced as a result of viewing the work. If it is, this results from the potency of a cultural tradition combined with the sublimity [...] of the natural sky and of infinite space."[4] The aerial-like ascending form of Kabakov's textual sculpture, and the association with Rodchenko's Pines, opens up further layers. Bachelard's meditations on the verticalising image, and the ‘aerial tree', and to Schopenhauer's pine at the edge of the abyss, and Nietzsche's fir tree "on the edge of the abyss, [which] is a cosmic vector of the aerial imagination."[5]
A rush of aerial reverie ... triggered by Martin Edmond's posting of Ludwig Becker's The Telegraph Tree... most definitely the epitome of an 'aerial tree'...
[1] Ursula Seibold-Bultmann (2000). New Projects for the City of Münster: Ilya Kabakov, Herman de Vries and Dan Graham. In Jan Birksted (ed). Landscapes of Memory and Experience. London: Spon. p. 219, n.6
[2] ibid, p.208.
[3] ibid, p.208-9.
[4] Ibid, p. 209.
[5] Gaston Bachelard. (1988). Air and Dreams: An essay on the imagination of movement. Trans. Edith R. Farrell and C. Frederick Farrell. Dallas: The Dallas Institute. P. 148. Originally published 1943 L'Air et les songes, essai sur l'imagination du mouvment.