Volume Calculations and Rules, Part 3: SilviaTerra’s Volume Calculation Method
Dr. Nan Pond
Dr. Nan Pond
28 April, 2015 min read

In the first post of this series, we discussed log rules in overview, and in the second we reviewed the shortcomings of form classes and why individual tree volume equations are preferable. Make sure to check those out, if you missed them.

This third part will highlight the methods and advantages of SilviaTerra’s volume calculation method – specifically, how our individual tree volume calculation methods are designed to save you time and energy.

At SilviaTerra, we use flexible, segmented equations for tree taper. Using the data you collect during your cruise, we fit a unique equation for each species you identify. Our team designs these equations to most closely represent the shape and taper of the specific trees from each cruise. This means that the equations will fit the trees in your stand, specifically. There’s no faster or easier way to get the highly reliable, customized volume estimates you need.

We’ve made it easy for you to record data while on your cruise. Our free app, Plot Hound, is available on the Appstore and Google Play. Its user friendly interface makes data entry quick and painless, and the app connects directly to our volume calculation system for automatic upload.

The more data you collect on your cruise, the better, but we use available historic data on similar trees in nearby areas to make estimates for measurements you don’t provide. For example, if you record the height, total or merchantable, for a particular stem, we will use the value you provide. But, if some of the stem measurements you record do not include a height measurement, we fill in the gaps using data from similar trees in your stand, and with historic data from similar nearby stands. This provides the most accurate estimate available.

When we receive your data, we analyze it to get a sense of your stand, especially the diversity of species and stem sizes. We compare what you’ve collected with data on the same species growing in similar conditions (such as stocking, location and species distribution) in nearby areas. Most of this data is publicly available from the U.S. Forest Service. Using their data provides us with more data points and allows for a more robust, and therefore more reliable, equation. The end result is a high-quality, custom-fit taper equation for every species in your stand.


Using these equations, we calculate volume on a stem-by-stem basis. We virtually ‘buck’ each measured tree into logs for the product or products that it may produce, based on the merchantability specifications you provide. Our system is designed to compute volumes in whatever units you need- cubic feet, tons, or board feet (International, Scribner, or Doyle).

The best part is that we’ve recently updated our system to get the results back to you more quickly than ever! Within a few hours, you’ll receive a free report on your data, organized into easy-to-understand tables.

If you need data analysis, we also offer more in-depth volume reports, which provide a summary of volumes by species and product, based on the ruleset you provide. Let us know ahead of time if you’d like to receive them so we can set you up in our system.

Plot Hound is the solution to your volume calculation needs. Give it a try! Please don’t hesitate to contact us if you have any questions or would like to receive our in-depth volume reports.

That wraps up our series on volume calculations and rules! We hope it has been a valuable resource for you.

Check back soon! We have more content and some exciting announcements coming just around the corner that you won’t want to miss. Subscribe to our blog or follow us on Facebook to stay up to date.

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about the author

Dr. Nan Pond

Dr. Nan Pond

Director of Certification
Dr. Nan Pond serves as the Director of Certification at NCX. She is responsible for ensuring that our natural capital products reflect the highest quality science as we hone our existing methods and expand into new credit types and new geographies. She is the recipient of the 2020 SAF Young Forester Leadership Award and has held multiple leadership roles within the Society of American Foresters. Dr. Pond earned a PhD in forest biometrics from Michigan Technological University and a Bachelor of Science in forest ecosystem science from SUNY ESF.