The poet's attitude to nature in "Birches" is fascinating. There is nature in the form of snow and ice - the elements, and there are the birches which in winter, are bent, covered by the ice - storms. They click and crack, but as soon as winter is over, the ice melts and the bent birches steady themselves once more, even though as never before.
The poet sees nature at work here, for though the ice-storms completely crush the birches, they rise again, which celebrates their resilience. On a light-hearted note then, nature in the form of the birches is a source of play. The poet recalls his childhood when he swung birches because of their resilience which enabled them to toss him up and down in great but frantic delight.
But there is another attitude to nature which is more serious. for it sustaining/. The poet refers to time that he is buffeted by all sorts of troubles and "life is too much like a pathless wood and when your face burns and tickles with cobwebs", which reminds him of the experience of the birches in nature. It is their ability to bend under the ice and come up again which he fondly recalls as he swung them as a school boy. That's the attitude to life he wishes to have - the never giving up attitude as he points out in the last line 'That could be good both going and coming back".

Points to note

(a) The categorisation of nature in the form of the elements- ice-snow storms and the birches.
(b) The beauty and the havoc wrecked by the elements on the birches and their ability to bounce back.
(c) The poet's attitude to nature/birches as a source of childhood play.
(d) His more serious attitude to the bircles as life sustaining in times of trouble.