From Spengler, The Decline of the West, Vol. I, 1922:
The character of the Faustian cathedral is that of the forest. The mighty elevation of the nave above the flanking aisles, in contrast to the flat roof of the basilica; the transformation of the columns, which with base and capital had been set as self-contained individuals in space, into pillars and clustered-pillars that grow up out of the earth and spread on high into an infinite subdivision and interlacing of lines and branches; the giant windows by which the wall is dissolved and the interior filled with mysterious light — these are the architectural actualizing of a world-feeling that had found the first of all its symbols in the high forest of the Northern plains, the deciduous forest with its mysterious tracery, its whispering of ever-mobile foliage over men’s heads, its branches straining through the trunks to be free of earth. Think of Romanesque ornamentation and its deep affinity to the sense of the woods. The endless, lonely, twilight wood became and remained the secret wistfulness in all Western building-forms, so that when the form-energy of the style died down — in late Gothic as in closing Baroque — the controlled abstract line-language resolved itself immediately into naturalistic branches, shoots, twigs and leaves.
(Illustration is Carl Blechen, Ruins of a Gothic Church, 1826.)