For trees, winter time is a time of drought. Water freezes in the ground and above ground as snow, and becomes unavailable. Without the water required for growth in the winter, trees actually initiate next year's growth in the summer. By the time winter comes around, miniaturized leaves and flowers are contained in scale-covered buds, waiting for spring and a combination of environmental cues which will trigger their unfolding and growth. So you see, winters in the city may look gray and sad, but in fact, below the surface is the potential of life: millions of unseen buds.
Unseen Buds by Walt Whitman
Unseen buds, infinite, hidden well,
Under the snow and ice, under the darkness, in every square or cubic inch,
Germinal, exquisite, in delicate lace, microscopic, unborn,
Like babes in wombs, latent, folded, compact, sleeping;
Billions of billions, and trillions of trillions of them waiting,
(On earth and in the sea--the universe--the stars there in the heavens,)
Urging slowly, surely forward, forming endless,
And waiting ever more, forever more behind.