Winter Buds

 

American Beech (Fagus grandifolia) leaf bud.
Rowan County, North Carolina. 

The woods are quiet in winter.  The bare trees look stark against the sky, but on their branches they bear buds that are ready to produce the new growth of spring.  The buds contain tiny flowers or leaves just waiting to open.  In late summer and fall trees stop growing and buds form. The buds enter a state of dormancy that have low water requirements and low metabolic rates.  Buds are covered by scales that protect the tiny leaves or miniscule flowers that are waiting out the winter. The scales are waterproof and provide shelter from the cold, dry winter weather.  

Pignut Hickory (Carya glabra) leaf buds.
Rowan County, North Carolina. 

Mockernut Hickory (Carya tomentosa) leaf buds.
Rowan County, North Carolina.

Painted Buckeye (Aesculus sylvatica) leaf buds.
Davidson County, North Carolina. 

As winter wanes, the bud dormancy is broken.  This is triggered by environmental signals, usually day-length and temperature.  The buds expand and the bud scales fall off.  The leaves or flowers of the bud unfurl, and the new year’s flush of growth begins.  

Red Maple (Acer rubra) flower buds.
These buds will open before the leaves
revealing red flowers. 
Rowan County, North Carolina.

Pinxter Azaela (Rhododendron periclymenoides) flower bud.  
Rowan County, North Carolina. 

Flowering Dogwood (Cornus florida) flower buds. 
Rowan County, North Carolina. 

The four scales of the Flowering Dogwood bud will open
and produce the four white bracts we think of as petals.
Small yellow-green flowers will be at the center.
Rowan County, North Carolina.   

When identifying trees, leaves are the main feature I use. However, most deciduous trees drop their leaves in the fall.  But in winter, buds are good tools to reveal a tree’s identity.  Bud shape, size, color and arrangement are all clues in identifying trees. 

American Sycamore (Platanus occidentalis) leaf buds.
Rowan County, North Carolina. 

Winged Elm (Ulmus alata) leaf buds.
Rowan County, North Carolina. 

Some trees we think of as deciduous do not drop their leaves in the fall but retain them throughout the winter.  This condition is called marcescence.  American Beech (Fagus grandifolia) and Oaks (Quercus sp.) are often marcescent.  The marcescent leaves are commonly found on young trees or on lower branches of larger trees. There are several hypotheses about the reason for this, including one that says the leaves protect the buds for the coming year.  

American Beech leaf bud with a marcescent leaf. 
Rowan County, North Carolina.  

Post Oak (Quercus stellata) leaf buds on a branch
with a marcescent leaf and acorn cap.
Rowan County, North Carolina. 

I enjoy the quiet of winter.  Seeing the tree buds, ready to start a new season, makes me smile because they are a foretaste of what is to come.    

Thanks to Dr. Jay Bolin for identifying the hickory buds.