The Sequentially Awakening Spring Forest

"The thing about being a tree is you're stuck there all winter in the cold. You've got a big stem and you're very exposed to the cold."
"If you look at an oak, for example, you can see pores in that wood -- big dead cells that are open. They are like straws, one stacked on the next. Or pipes."
"And those specialized cells move water. And what the tree has to do is produce a new set of pipes before it can leaf out. Or around the same time [while producing the pipes] it can leaf out. It has to have a plumbing system to get the new leaves."
"So in those species like oaks, the wood will start growing before the trees leaf out, and produce a new plumbing system for the year."
"All of this is about synchronizing with the season [flowering spring wildflowers advantaged by the sun warming the forest floor before deciduous trees leaf out blocking the sun]."
"Things are constrained by when it gets warm enough. But if the overstory trees are deciduous, there is lots of light available for those very early spring plants, so ... they can photosynthesize and grow and flower before they are heavily shaded."
"The result is that we get this beautiful sequence of plants that really give us a sense of season because things are happening at different times."
Sally Aitken, researcher, associate dean of forestry, University of British Columbia

On spring's arrival, a steady succession of early season changes begin to take place. At less than dizzying speed, it often seems, for those anxious to see the woods transform from the sere appearance of winter, with its monotones of black, grey and white. It takes a considerable length of time, when the atmosphere is in its warming phase, the sun rises higher in the sky and becomes notably warmer, and copious spring rain along with snowmelt irrigates the roots of trees in the forest, both deciduous and coniferous.

Pink Trillium

We see the gradual appearance of familiar woodland plants on the forest floor as ferns begin to poke through the warming soil and unfurl, when woodland violets begin their bloom, along with coltsfoot, resembling early dandelions, and in North America trilliums and Ladies Slipper orchids, Trout lilies and Jack-in-the-Pulpits make their appearance. They take advantage of the leafless deciduous trees which, when fully leafed, block the sun from warming the forest floor, to make the most of that brief time, to flourish and to flower.

When we look up at the forest canopy and see the bare branches of conifers it seems to take forever before poplars, elm, maples, beech, birch and oak among others finally begin to leaf out. They do so gradually, some species earlier than others, until eventually all are in leaf. And though we're impatient about the process, anxious to see that familiar, reassuring green screen of foliage, the trees themselves are doing their best to prepare for leafing out, unknown to us.

Trout Lilies

Evergreens, though they keep their green throughout the winter months, also begin to produce new 'foliage' in spring needles, casting off the old dead ones. They begin the process of photosynthesis quicker than the trees that have shed their foliage in fall. All trees use sunlight to produce food as sap begins to run up from their roots to suffuse the entire tree and begin the process of renewal. The ritual of the deciduous trees is locked into their cells absorbing water.

They have been deprived during the winter months of liquid, awaiting spring when the cells that pick up water are once again fully functioning, casting off the air bubbles that result in the winter when water freezes in the cells and growth is apprehended. And while the trees are awakening and resuming their growth periods throughout the warm months that follow, photosynthesizing to put out new foliage, the forest has long since awakened, as evidenced by the wide array of spring-flowering plants taking their turn, one after another.