Is this a good thesis for Robert Frost's "Birches"?
Robert Frost’s poem, "Birches" portrays the relationships between imagination and truth, escape and boundaries, and conquest and defeat, and enlightens its readers on the act of balancing these ideas.
Since "Birches" by Robert Frost is about a man--one supposes from the intimate perspective of the poem that the poetic voice represents the poet himself--for whom the sight of the results of ice storms on birch trees awakens memories and calls forth associations, your proposed thesis ("relationships between imagination and truth, escape and boundaries, and conquest and defeat, and enlightens its readers on the act of balancing these ideas.") seems an excellent one. In the birch trees, the speaker sees with his mind's eye the imaginary youth who bowed the trees in play, an image that is both imagination and memory, which is a type of truth, ("So was I once myself a swinger of birches").
The end of the poem definitely calls up the theme of escape from the cares of life and emphasizes boundaries when the speaker emphasizes that the escape he would wish for would be another swing on the birches ("That would be good both going and coming back"). Conquest is definitely an idea in the relationship between the boy and the birch trees, and defeat is indirectly implied in the speakers lament of present woes:
It's when I'm weary of considerations,
And life is too much like a pathless wood
Where your face burns and tickles with the cobwebs
Broken across it, and one eye is weeping
I think your thesis will lead to a compelling and worthy examination of "Birches" by Robert Frost.
I like the way you have clearly set yourself up for a paper that can be clearly organized into three parts. On first reading of this thesis, my criticism was that it was starting to sound like a run-on. I also had trouble with the the idea of the "relationships between" each pair of words. It is almost too generic. Finally, when setting up parallel ideas (imagination and truth; boundaries and escape; conquest and defeat) you need to make sure that you are dealing with a "like-pair." Simply put, try to describe the balance of two ideas that are both the same part of speech (ie: both nouns, verbs, adjectives, etc).
It sounds like what you are trying to say should go a little something more like this:
Robert Frost's poem, "Birches," portrays the delicate balance between imagination versus truth, boundaries versus freedom, and conquest versus defeat.
The italicized words above are possibly still not perfect and could be tweaked, but it sounds to me like this is more the paper you are trying to write.
Otherwise, great start. It sounds like this has the potential to be a very strong essay if this is where you are beginning.
I do think you have a solid start on a thesis statement here. You clearly identify author and title of the work you are analyzing and preview for your reader the major topics you will discuss: the juxtaposition of imagination and truth, escape and boundaries, and conquest and defeat. I would only offer two suggestions: (1) be sure to place the title of the poem in quotation marks, and (2) try to include some mention of the literary or poetic devices that are used within the poem to communicate these relationships and ideas. How are they emphasized for the reader? In what ways does their use enhance and clarify these relationships? Including these elements in your thesis statement will strengthen the quality of your literary analysis.