Lesson 1:
The Architecture of Your Forest
Have you ever wondered why your woodlot contains a variety of species and tree sizes?
If your woodlot has not been harvested recently then you can assume that most of your
trees are the same age, even if they are not the same size. Forests that contain hardwood
species such as oaks and maples, not pines, tend to grow in layers. These layers of forest
canopy are arranged from top to bottom according to those species that need full sunlight to
grow and those that can grow in shade. The species at the top layer, or
overstory, also happen to be the
species that are the most valuable in the Appalachian region: Oaks, black cherry, and yellow-poplar.
These species grow the largest and straightest and have the highest value for sawlogs (See Lesson 2).
Species in the lower canopy layers, or understory, receive less light and tend to grow slower and be
smaller than those trees at the top. Some typical species in the understory are red maple, beech,
and black gum. These species have low value for sawlogs due to poor stem quality and low market demand.
Trees in the overstory such as yellow-poplar, depicted in the image below
(left) as the yellow crowns, and oaks (blue crowns) need more sunlight to grow
than red maple (red crowns). The photo below (right) shows a stand of
trees the same age even though some are much smaller. The smaller trees
in the understory grow slower because they are shaded by the overstory.
Lesson 2
