Winter’s over, the days are getting longer, buds are beginning to burst and the birds that come north in the spring are arriving. Here in the eastern deciduous forest the leaves on the hardwoods lost their chlorophyll last fall and began to fall to the ground. For months the hardwood trees have spread bare branches to the winter sky –
But not all deciduous trees have been without leaves throughout the winter. Some species have a tendency to retain some or most of their leaves. Those leaves are dry and brown, but they’re still on the branches. Younger trees exhibit this tendency more than their older brethren.
Last fall as the days shortened a corky layer developed where the leaves' petioles (stems) joined the twigs. This is called the abscission layer and cuts off the water supply to the leaf, resulting in the death of the green chlorophyll in the leaf. Thus all the leaves died and turned color brightening the forest with their shades of red, yellow and orange. The abscission layer weakens the bond between the leaves and the twigs and the leaves fall to the ground.
Except not all the leaves fell, some hung on through the rain and snow and wind – and still hang on.
By mid-May the buds on most of our trees will be open, and the new leaves will be expanding pushing the few remaining old leaves from the twigs.