The speaker uses a highly excited tone when speaking about nature. He recollects his own past experience with nature and describes its present influence on him, but he keeps the tone of exultation all the time. He admits that his past experience with nature was a shallow, boyish one, devoid of deeper understanding; back then, he was able to only enjoy the nature's beauty, but now he is able to understand its profundity and interconnectedness. The latter brings a calmer, more philosophical mood into the poem.