Skip to main content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Biomass Volume Estimation

The National Biomass Estimator Library (NBEL) was developed by the Forest Management Service Center (FMSC) as a sister library to the National Volume Estimator Library (NVEL). Both open-source libraries provided a standard interface for the inclusion of volume and biomass models into cruising, planning, and stand exam software and are available as Excel functions. The Service Center provides training, tools and software for model validation and development.

National Biomass Estimator Library (NBEL)

The National Biomass Estimator Library (NBEL) is a collection of equations from various biomass studies available as a database (sqlite) or as a dynamic link library (dll) accessible to programmers. The dll is also available a Microsoft Excel Add-in which can be downloaded below. The Forest Management Service Center maintains and houses the code which is available upon request.

  • Excel Biomass Functions (, 03-08-2018, 6 MB)
  • Biomass Library Equations Viewer/Tester (, 09-27-2019, 3 MB)
    A Visual Studio 2008 project that contains a simple C# form interface to the NBEL along with the actual dll and the database. The NBEL Tester/SetUp interface allows you to view biomass equation in the library, test biomass calculation, view and test regional/forest default equations, and view Excel AddIn functions for each component. The NBELTester can be installed from NBELTesterSetup.msi (Install Evevated).
  • Biomass Library C++ DAL (Visual Studio 2008 project) (, 04-13-2011, 3 MB)
    A Visual Studio 2008 project that contains the NBEL c# dll as well as a C++ data access layer (DAL) and an example of how to use the C++ DAL.
  • NBEL SQLite Database (, 09-27-2019, 1 MB)
  • NBEL Documentation (NBEL_20190509.docx, 05-15-2019, 293 KB)

Randomized Branch Sampling (RBS)

Randomized branch sampling (RBS) is a special application of multistage probability sampling originally used to estimate fruit counts on individual orchard trees. In general, the method can be used to obtain estimates of many different attributes of trees or other branched plants. We have adapted RBS to estimate crown (branch, leaf and non-merchantable) biomass with the intention of developing regression equations for predicting crown biomass based on common tree metrics (species, dbh, height).