And baffled by the beeches

 Lest you be led astray by yesterday’s note, I’m baffled by many things here, not just the red maples.

The American beech, Fagus grandifolia, is one of the marker species for what the ecologists call “Piedmont mesic forests.” They are moist and protected.

One of the most famous around here is Depedene. As the name suggests, it’s sheltered in a deep ravine. The mesic forest I’m watching is on the south edge of Stone Mountain, which shelters the woods from north winds.

In places, the beeches are dominant and, though they are deciduous trees, they have held almost all their leaves through winter. The leaves turn bronze and then bleach to a khaki color. The khaki has faded for the past two months.

It’s a sight that still astonishes me, coming through the bare woods to the beautiful stand of beech.

Trees that hold their leaves through winter are called marcescent. Each leaf stalk, called a petiole, is joined to a branch by a layer of tissue that has a lot of small tubes, like veins. The tubules carry water and nutrients between the leaf and the rest of the tree. In the fall, cells in this abscission layer secret a waxy substance that gradually shuts off the flow of water and nutrients. The leaves eventually fall without leaving a wound on the branch.

Some species, including American beeches, don’t develop that waxy substance. They hold their leaves until the new ones arrive in spring.

It's mostly genetics. But some trees can be marcescent as juveniles and grow out of it.