Not all selected poems volumes are arranged by order of composition (and in this instance the publishers give us no clue), but I always tend to read them that way, and in this instance the succession of poems did suggest the progress of a career. Early on, a certain Eliotesque quality in which the landscapes seem more metaphysical than actual, even tipping into allegory -- then a Whitmanian era, long-lined, deep-breathed poems embracing process and heterogeneity -- then short-lined, imagistic poems (W.C.W.?) dropping down the page like a plumb line -- then a phase of unrhymed, heavily enjambed terza rima.
These last seemed to me the least compelling -- there's even a poem, "Sorting," which by talking about how dry the heights are suggests that inspiration can slow to a trickle with age. But some of the late stuff is superb: "Easter Morning," for instance, which reminded me a lot of Terrence Malick's Tree of Life, which I saw only a couple of days ago -- the shards of memory, the insolubility of the past, the profusion of the natural world, the sudden sucker-punch of grace.
Easy to see why Harold Bloom thought well of Ammons -- deep affinities with Wordsworth, Shelley, Whitman, Stevens, consciousness in dialogue with nature, identifying with it at one moment, insisting on its difference in another, interrogating, surrendering. The wind seems to be Ammons's totemic image throughout his career, going through a spectrum of permutations: "So I Said I Am Ezra," "In the Wind My Rescue Is," "Guide," "Project," "Small Song," "Conserving the Magnitude of Uselessness."