Glossary of Forestry Terms

The New Hampshire Tree Farm Program, an organization that encourages private forest owners to actively manage their forests in a sustainable manner, produced a helpful guide of key forestry terms. We appreciate their work and have included a copy of their glossary here.

For more information, please check out their website:

Basal Area: Sum of the cross-sectional areas (at 4.5 ft high) of all trees on an acre. A measure of stand density or crowding.

BMPs: Best Management Practices refers to the proper methods for the control and dispersal of water and runoff on truck haul roads, skid trails, and log landings to minimize erosion and reduce sediment and temperature changes in streams.

DBH: Diameter at breast height, 4.5 feet above the ground.

Cavity Tree/Snag: A living tree with a hollow cavity large enough to shelter wildlife. Also called a den tree.

Forest Type: A distinctive association or community of trees, shrubs, and herbaceous plants. They are named for the predominant tree species occurring in the type.

High Conservation Forests: Forests of outstanding and critical importance due to their environmental value.

Mast: The seed and fruit of a tree or shrub. Hard mast includes nuts, and soft mast includes catkins, berries and other fruits.

Prescription: A course of action to effect change in a forest stand.

Regeneration: Seedlings and saplings established in the understory.

Silviculture: The art and science of growing trees.

Size Classes: Trees are classified by size into four classes: Seedlings; trees less than 4.5 feet tall and less than 1 inch in diameter. Saplings; trees 1-4 inches in diameter and at least 4.5 feet tall. Poles; trees between 5-10 inches in diameter. Sawtimber; trees larger than 10 inches in diameter at breast height.

Special Sites: Those areas offering unique historical, archeological, cultural, geological, biological or ecological value.

Stocking: An indication of the number of trees in a stand as compared to the optimum number of trees to achieve some management objective. (i.e. overstocked, adequately stocked, under stocked).

Overstory: The trees in the main canopy. Pole and sawtimber sized trees.

Understory: The seedlings and saplings that grow on the forest floor, including tree species that have not grown large enough to enter the main canopy.

Vernal Pool: Small, temporary wetlands that form in the spring from rain or snowmelt. They are important to many wildlife species, but are especially critical to amphibian reproduction. Because the pools are seasonal, fish are not present as predators.

Uneven Aged: A stand of trees that contain at least 3 well defined age classes (20 or more years apart).

Even Aged: A stand of trees where most of the trees are the same age (within 20 years) or in the same size class.

Good Forestry in the Granite State: A free publication by the NH Division of Forests and Lands, DRED, which outlines BMP’s to be followed during timber harvesting operations.

Crop Tree: A pole or sawlog sized tree that is healthy and free of defects that should be re-leased to extra sunlight to increase growth for future harvest.

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We can also assist you with Timber Harvesting, Timber Appraisals, Land Acquisition, Stewardship and Current Use, GIS Mapping, Forest Health Evaluations, Boundary Line Maintenance, Sugarbush Management, Wildlife Habitat, View Creation, and Forest Roads and Trail Building. We are New Hampshire and Vermont’s premier, licensed, forestry professionals. If there is still another forestry or logging service you are looking for, please contact us. We work with a large network of other industry professionals and would be delighted to help you in the right direction. We look forward to hearing from you.