Managing your forest land – Landowners Top-10 Frequently Asked Questions
US Forest Service, State and Private Forestry – Northeastern Area
Forest Stewardship Program

3. How much tree volume is in my woods, and how fast can I expect my trees to grow?

Tree volume describes the quantity of wood in a tree, on an acre, or in a section of forest. Just as apples are sold by the peck and milk by the gallon, wood is usually bought and sold by volume--“board feet” or “cords”--or by weight, depending on the products intended from the trees.

How much wood volume is in my forest?
Because wood is bought by volume, knowing the volume of wood in the trees in your forest will help you make management decisions.  Tree measurements of diameter and height can be compared with tables that identify board foot or cord volumes.  Computer savvy forest owners can use mathematical formulas to estimate volume.  Your local Cooperative Extension office will likely have publications on how to measure an individual tree to estimate its volume.  Your service forester or a trained volunteer can help you get started on this process. There are also private consulting foresters with extensive experience who are trained to develop volume estimates of woodlands. Although you will pay for this service, you will have a reliable estimate not only of volume, but also of the market value, since foresters operate in the timber marketplace all the time.

How can I estimate how much high-value wood is in my trees?
If you sell high-value trees for use as lumber or veneer, you will sell the trees based on the board feet they contain. A board foot is 1 inch by 12 inches by 12 inches or 144 cubic inches. When a tree is standing, the board foot estimate uses tree height and diameter, normally measured at 4.5 feet above ground. These standing tree measures estimate the tree scale . One either enters tree scale measures into a formula or compares them with a table that estimates the tree volume. There are a few common tree scales, such as International ¼ inch, Doyle, and Scribner, but dozens of others are used throughout the region.  Different formulas provide different estimates of volume because of the way they were developed and the assumptions they make. The actual formula or table used does not matter that much; it is more important that you know which scale you used and that you compare estimates using the same scale. Volume estimation of a tree cut into logs uses the small-end inside bark diameter and log length. Again, a table or formula estimates the log volume.

How can I estimate how much low-value wood is in my trees?
If you sell trees that are of low value or “ low-grade ” (for example small diameter or undesired species), the common measure is cords or perhaps weight. A “standard cord” is a stack of wood measuring 4 feet by 8 feet by 8 feet and contains 128 cubic feet. Solid wood occupies approximately 80-85% of the volume of a cord; the remainder is air space and bark. Cords describe wood sold for pulp, firewood, or chips. A "face cord" or "rick" is a common measure for selling firewood and measures 4 feet by 8 feet, but the length of the sticks will vary, for example, from 12 to 18 inches. Weight is an easy measure if you have access to scales.

How much wood will my trees add as they grow?
Foresters (FAQ 1) also have tools and techniques that can reasonably estimate future growth of timber volume. The growth rate of trees varies considerably across a state and even on a single property. The variables that most affect tree growth include differences among tree species, competition for sunlight, tree age, and soil conditions. Unlike animals that stop growing at maturity, trees need to continue to grow to maintain vigor and health. For many species, when growth slows or stops the tree will die soon after. At a young age (typically up to about 10 inches in diameter), trees will grow in both diameter and height. As trees get older and larger, their annual height growth decreases but their diameter growth continues. The width of the annual ring will decline as the same amount of wood is spread around an increasing longer circumference of tree stem.  Trees in a closed canopy forest may grow slowly at approximately 1 inch of diameter per decade. Trees in a managed forest with appropriate tree species for the area and on good soils might grow up to 3 or 4 inches of diameter in 10 years.  On a cut stump, this represents 5 growth rings in the outer inch of wood.  Slower growth might be 10 to 30 rings per outer inch of wood on a cut stump.  Growth rate often has a strong positive influence on tree health. As trees increase in size, they gain volume. In addition, they may also increase in quality as they add more volume.

Where can I find more information?
For more information about tree volumes and utilization, contact your local forest owner association or Cooperative Extension office to see about a group tour of a local sawmill. Understanding how mills use logs of different qualities will help you grow better trees.


Recommended Web links

Estimating tree volume

Volume tables and log rules

Tree value

Tree growth rates

Computer software