The warming weather and fresh breezes lift my heart but it is the appearance of fresh green hues one after another that truly thrills me in the spring. In early March the greening begins on the forest floor, dances its way through the understory in April, and continues up through the tree canopies by May. Small wildflowers bloom early to catch sunlight that will soon be blocked by hungry tree leaves. These blossoms are essential to the survival of early awakening pollinators. And so the intimate tapestry of nature weaves itself into summer.
As the level of green approaches our shoulders, a curiously corrugated native is appearing in the wet areas of Angle Fly Preserve. False Hellebore (Veratrum viride) can grow nearly tall as a person as its spiral of leaves unfurl. Soon, clusters of little bright green blossoms will dangle above the plant. A member of the lily family, false hellebore is highly toxic if ingested. So the usual advice holds: look, photograph, enjoy, and leave it in peace.
But not all is green. Look up: among the colorful haze of tree buds are limbs broken in the Halloween storm which sport clusters of dry brown leaves. These reveal a little-known detail about how leaves turn color and fall off their trees in the autumn. Like the twist in a detective story, the truth is the leaves do not fall – they are pushed!
To prepare for the freezing winter, deciduous trees produce a layer of abscission cells between each twig and leaf. These cells form a barrier that stops the circulation between leaf and branch and snips them from the tree. This initiates both the color changes and the leaves’ descent to earth where they are broken down by other organisms into nutrients for the tree’s renewal in the spring. Since these branches were broken before the trees had a chance to develop abscission cells, the leaves never turned color nor received that final shove.