Rather bluntly, a harmonic analysis of this work is not much interesting. The entire composition is based upon I going to V… and that’s it. Honestly, the almost the entire piece is I V I V I (with minor [ha!] variations/chords other than tonic or dominant sprinkled sparsely). Instead of playing with the text on a chord-by-chord basis Schubert inflects the varying stanzas into large-idea sections, literally changing key to emulate the different emotions.
The first two stanzas starting “By the fountain” and “I carved on its bark” are in E major, depicting joys and sweet memories. However the stanza beginning with “I had to pass it again today” is in e minor, the dread here being the passing of the tree “in the dead of night.” This stanza leads one to believe something bad or frightening happened at night or somehow Schubert wanted to show how even passing the tree in darkness created a clamor of emotion. “Even in the darkness I had to close my eyes”… a clear indication that something terribly frightening and unpleasant happened to that individual with which he continues to struggle. It is the performer’s duty to convey this sense of dread and despair convincingly and with a personal conviction. Unlike previous sections which had introductions to prepare the mood, the performer must instantaneously recall the good of the tree; as if the sun jumped out from behind the tree, glowing and warming all things. The tree beckons, “Come here…you will find your peace!” But a peace was not meant to be, as the sun drops quickly and the frigid wind cuts the skin and whips your hat away– you take hot pursuit to find your hat, not looking back or giving the tree a second glance. Here is yet another key change where one finds himself in musing, attempting to recall the offer the tree gave you: “Come here, to me, friend, here you will find your peace!” You ponder whether it was a good idea to leave that tree in plight. Eventually (through much repetition) you concede that you would have found satisfaction at the tree and “hear the rustling” of the leaves calling you. This all is still not enough to recall you to that spot, but apparently you’re in high enough spirits to end on an E major chord.
Overall, Schubert’s Der Lindenbaum has a lot to offer to the performer. As for analyzing, not so much: the only somewhat interesting section is from measures 45-57 where the harmonic progression leads from bVI to V, back and forth until the end of that section. It’s a strophic verse composition that has introductions/interruptions metered in at places that help effectively set the mood. If the performer can visualize himself (or herself) as the individual recalling these events they will be better suited to concoct a convincing portrayal of the music and captivate an audience. It’s a difficult proposition, especially in a foreign language but one that every musician must overcome, whether vocal or instrumental: reach the audience by any means possible.