Herodotus 7.31 (tr. A.D. Godley):
Passing from Phrygia into Lydia, he came to the place where the roads part; the road on the left leads to Caria, the one on the right to Sardis; on the latter the traveller must cross the river Maeander and pass by the city of Callatebus, where craftsmen make honey out of wheat and tamarisks. Xerxes went by this road and found a plane-tree, which he adorned with gold because of its beauty, and he assigned one of his immortals to guard it. On the next day he reached the city of the Lydians.
ὡς δὲ ἐκ τῆς Φρυγίης ἐσέβαλε ἐς τὴν Λυδίην, σχιζομένης τῆς ὁδοῦ καὶ τῆς μὲν ἐς ἀριστερὴν ἐπὶ Καρίης φερούσης, τῆς δὲ ἐς δεξιὴν ἐς Σάρδις, τῇ καὶ πορευομένῳ διαβῆναι τὸν Μαίανδρον ποταμὸν πᾶσα ἀνάγκη γίνεται καὶ ἰέναι παρὰ Καλλάτηβον πόλιν, ἐν τῇ ἄνδρες δημιοργοὶ μέλι ἐκ μυρίκης τε καὶ πυροῦ ποιεῦσι, ταύτην ἰὼν ὁ Ξέρξης τὴν ὁδὸν εὗρε πλατάνιστον, τὴν κάλλεος εἵνεκα δωρησάμενος κόσμῳ χρυσέῳ καὶ μελεδωνῷ ἀθανάτῳ ἀνδρὶ ἐπιτρέψας δευτέρῃ ἡμέρῃ ἀπίκετο ἐς τῶν Λυδῶν τὸ ἄστυ.
Aelian, Historical Miscellany
2.14 (tr. N.G. Wilson):
The famous king Xerxes was ridiculous, if it is true that he despised sea and land, the handiwork of Zeus, manufactured for himself novel roads and abnormal sea routes, and yet was the devotee of a plane tree, which he admired. In Lydia, they say, he saw a large specimen of a plane tree, and stopped for that day without any need. He made the wilderness around the tree his camp, and attached to it expensive ornaments, paying homage to the branches with necklaces and bracelets. He left a caretaker for it, like a guard to provide security, as if it were a woman he loved. What benefit accrued to the tree as a result? The ornaments it had acquired, which were quite inappropriate to it, hung on it without serving any purpose and made no contribution to its appearance, since the beauty of a tree consists of fine branches, abundant leaves, a sturdy trunk, deep roots, movement in the wind, shadow spreading all around, change in accordance with the passing of seasons, with irrigation channels to support it and rain water to sustain it. Xerxes' robes, barbarian gold, and the other offerings did not ennoble the plane or any other tree.
Γελοῖος ἐκεῖνος ὁ Ξέρξης ᾖν εἴ γε θαλάσσης μὲν καὶ γῆς κατεφρόνει τῆς Διὸς τέχνης, ἑαυτῷ δὲ εἰργάζετο καινὰς ὁδοὺς καὶ πλοῦν ἀήθη, δεδούλωτο δὲ πλατάνῳ, καὶ ἐθαύμαζε τὸ δένδρον. ἐν Λυδίᾳ γοῦν, φασιν, ἰδὼν φυτὸν εὐμέγεθες πλατάνου, καὶ τὴν ἡμέραν ἐκείνην κατέμεινεν, οὐδέν τι δεόμενος, καὶ ἐχρήσατο σταθμῷ τῇ ἐρημίᾳ τῇ περὶ τὴν πλάτανον. ἀλλὰ καὶ ἐξῆψεν αὐτῆς κόσμον πολυτελῆ, στρεπτοῖς καὶ ψελλίοις τιμῶν τοὺς κλάδους, καὶ μελεδωνὸν αὐτῇ κατέλιπεν, ὥσπερ ἐρωμένῃ φύλακα καὶ φρουρόν. ἐκ δὲ τούτων τι τῷ δένδρῳ καλὸν ἀπήντησεν; ὁ μὲν γὰρ κόσμος ὁ ἐπίκτητος καὶ μηδὲν αὐτῷ προσήκων ἄλλως ἐκρέματο καὶ συνεμάχετο εἰς ὥραν οὐδέν, ἐπεὶ τοῦ φυτοῦ κάλλος ἐκεῖνό ἐστιν· εὐγενεῖς οἱ κλάδοι καὶ ἡ κόμη πολλὴ καὶ στερεὸν τὸ πρέμνον καὶ αἱ ῥίζαι ἐν βάθει καὶ διασείοντες οἱ ἄνεμοι καὶ ἀμφιλαφὴς ἡ ἐξ αὐτοῦ σκιὰ καὶ ἀναστρέφουσαι αἱ ὧραι καὶ ὕδωρ τὸ μὲν διὰ τῶν ὀχετῶν ἐκτρέφον, τὸ δὲ ἐξ οὐρανοῦ ἐπάρδον· χλαμύδες δὲ αἱ Ξέρξου καὶ χρυσὸς ὁ τοῦ βαρβάρου καὶ τὰ ἄλλα δῶρα οὔτε πρὸς τὴν πλάτανον οὔτε πρὸς ἄλλο δένδρον εὐγενὲς ἦν.
Frank H. Stubbings, "Xerxes and the Plane-Tree," Greece & Rome
15 (1946) 63-67 (at 63):
The criticism is rational. But Aelian, who though he wrote in Greek is recorded never to have left his native Italy, could hardly appreciate the feelings of admiration and delight, even of religious awe, shown by the dwellers on the arid plateaux of Asia for large and shady trees, feelings shared by the Greeks, and by any modern traveller in Greece who on a dusty summer's day has spied far-off a whitewashed chapel with trees at hand, and known that there he would also find a spring of cold clear water and rest from the road.
For similar feelings of admiration, delight, and religious awe, see Aldous Huxley, "In a Tunisian Oasis":
In the middle of the desert, suddenly, a hundred fountains come welling out of the sand; rivers run, a network of little canals is dug. An innumerable forest of date palms springs up—a forest whose undergrowth is corn and roses, vines and apricot trees, olives and pomegranates, pepper trees, castor-oil trees, banana trees, every precious plant of the temperate and the sub-tropical zones. No rain falls on these little Edens—except on the days of my arrival—but the springs, fed from who knows what distant source, flow inexhaustibly and have flowed at least since Roman times. Islanded among the sands, their green luxuriance is a standing miracle. That it should have been in a desert, with here and there such islands of palm trees, that Judaism and Mohammedanism took their rise is a thing which, since I have seen an oasis, astonishes me. The religion which, in such a country, would naturally suggest itself to me would be no abstract monotheism, but the adoration of life, of the forces of green and growing nature. In an oasis, it seems to me, the worship of Pan and of the Great Mother should be celebrated with an almost desperate earnestness. The nymphs of water and of trees ought surely, here, to receive a passionate gratitude. In the desert, I should infallibly have invented the Greek mythology. The Jews and the Arabs discovered Jahweh and Allah. I find it strange.