Forestry Terms & Tree Care Vocabulary
Common forestry and tree care terms explained — canopy, DBH, silviculture and more. Learn the lingo before your project.
Age class
A group of trees within a stand or forest that are roughly the same age plus or minus 10% of the range of rotation.
AGS/UGS
Acceptable growing stock/unacceptable growing stock. AGS trees are relatively straight, either have or will have a sawlog in them, are sound, &/or help meet some management objective such as wildlife food or cover, or biodiversity. They are generally the kind of trees that should be left in the stand after the harvest is complete. UGS do not have these qualities and should be the first to be designated for removal.
BA (Basal area)
The cross-sectional area of the tree at 4 ½ feet above the ground.
BF (Board feet)
One board foot of lumber is 12” x 12” x 1”.
Canopy
The upper layer of the forest, formed by the crowns of the tallest trees.
Codominant
Trees which are in the canopy layer of the forest but do not have the entire top of their crowns exposed to direct sunlight.
Crown
The upper part of the tree including the leaves & branches.
Cruise
To measure trees prior to harvest. Diameter is measured at 4 ½ feet above the ground using a diameter tape, Biltmore stick or caliper. Height is estimated, and the data is entered in a table to be converted into board feet estimated.
DBH (Diameter at Breast Height)
The diameter of a tree at 4 ½ feet above the ground on the uphill side of the tree.
Fell
To cut a tree down. Felling: the work of cutting the tree down.
Forwarder
An all-wheel drive machine designed to be driven in the woods. Its job is to carry trees, cut to log length, from the forest to the landing. It is equipped with a loader to lift the logs onto the back of the machine.
Landing
The location where logs from the woods are brought so that they can be loaded onto a truck to be hauled to market.
Overstory
The trees which collectively make up the canopy.
Pioneer
A sun-loving tree species that invades old fields early in succession.
Residual
Trees which will remain in the forest after the harvest.
Rotation
The length of time it takes to grow a crop of trees to economic maturity.
Shade intolerant
Trees which require full sunlight to survive. They are usually fast growing & relatively short-lived (80-120 years)
Shade tolerant
Trees which can survive in the shade of others for a prolonged period. When the trees above them die, they are ready to grow into the vacancy.
Silviculture
The art & science of forest establishment, growth, management & renewal.
Skidder
A four-wheel drive tractor equipped with a winch and sometimes a grapple. It is used to drag (skid) trees from the forest to the landing.
Stumpage
Trees to be removed during harvesting.
Succession
The progression of cover types from grasses to shrubs to shade intolerant trees to shade tolerant trees