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The Compilation Reports section below provides details about the compilation reports that can be generated by InventoryManager including the types of tables that can be produced and calculations that can performed.
Height Estimation (Dubbing)
Profile functions typically require a total tree height measurement. Many foresters do not measure total heights for all trees due to the level of effort that total height measurements can take.
If a species has at least 3 trees with measured tree heights, heights for all other trees for that species will be estimated by fitting the Wykoff (Wykoff, et al. 1982*) equation using ameba function
HT = 4.5 + exp (B1 + B2 / (DBH + 1.0))
where:
HT is tree height
DBH is tree diameter at breast height
B1 - B2 are species-specific coefficients shown in table 4.1.1
If a species does not have at least 3 trees with measured tree heights, default coefficients from the FVS User Guide for the relevant region and species are used.
Additional height estimation equations can be added if needed.
*Wykoff, William R., Crookston, Nicholas L., and Stage, Albert R. 1982. User’s guide to the Stand
Prognosis Model. Gen. Tech. Rep. INT-133. Ogden, UT: Forest Service, Intermountain
Forest and Range Experiment Station. 112p
Volume Calculations
WSG’s compilation routine supports a range of profile equations and volume tables as described below.
Profile Equations - National Volume Estimator Library
The WSG’s compilation routine implements profile equations via the National Volume Estimator Library (NVEL). NVEL is a software library developed and maintained by the US Forest Service. It implements a large number of published taper functions and volume equations. NVEL is used within other applications developed by the US Forest Service, including the Forest Vegetation Simulator https://www.fs.fed.us/fvs/index.shtml and the National Cruise Program https://www.fs.fed.us/forestmanagement/products/measurement/cruising/fscruiser/index.php. It provides tools that allow access to NVEL functions within Excel and R, as well as interfaces to call NVEL functions from software development languages such as Visual Basic and C#. More information about NVEL can be found at https://www.fs.fed.us/forestmanagement/products/measurement/volume/nvel/index.php . InventoryManager includes a custom cloud-hosted implementation of NVEL and uses this to apply default or user-selected equations to merchandize trees and calculate volume. It combines the field-measured values, NVEL taper equations and user-defined merchandising specs to achieve industry standard volume calculations at locations throughout the US. InventoryManager then compiles these tree level data and provides reports at the stand or sale level, allowing for a range of groupings, units, statistics, and report layouts.
Below is the list of Profile Equations included in the National Volume Estimator Library. These can be used in conjunction with the WSG merchandiser to calculate tree volume according to any custom merchandising spec. Equations and merch specs can be applied at the species and/or product level. It is even possible to combine volume tables and equations. For example, it is possible to use a profile function (e.g., Clarke’s profile function) to calculate to calculate topwood in combination with a volume table (e.g., Mesavage & Girard) for saw timber.
Behre's Hyperbola (Bell & Dilworth, 1988).
Clark Profile model (Clark et al. 1991. Southeastern For Exper Station. Research Paper SE-282).
Czaplewski's 2 point profile model (Czaplewski et al 1989. Research Paper RM-284).
Czaplewski's 3 point profile model (Unpublished. Based on work presented in Czaplewski & McClure. 1988. Forest Science, Vol. 34, pp. 512 – 522).
DeMars and Bruce profile models (Donald Demars. 1996. Pacific Northwest Res. Station Research Note. PNW-RN-517) & (Bruce, D., 1984. Volume estimators for Sitka spruce and western hemlock in coastal Alaska. In Inventorying forest and other vegetation of the high latitude and high altitude regions. SAF pub 84-11. Bethesada, MD. pp. 96-102).
Flewelling's 2 point profile model (Unpublished. Based on work presented by Flewelling and Raynes. 1993 Canadian Journal of Forest Research Vol 23. Part I and Part II).
Flewelling's 3 point profile model (Unpublished. Based on work presented by Flewelling and Raynes. 1993 Canadian Journal of Forest Research Vol 23. Part I and Part II).
Rastagi and Loveless profile model (Rustagi, K.R. and Loveless, R.S.,Jr., 1991. Compatible variable-form volume and stem-profile equations for Douglas-fir. Can. J. For. Res. 21:143-151).
Sharpnack's 2 point profile model (Sharpnack, David A. 1966. Predicting Volumes in Four Hawaii Hardwoods. Southwest Forest and Range Research Station Research Note SW-121)
Wensel and Olsen 2 point profile model (Wensel, L. C. and C. M. Olson. 1993. Tree Taper Models for Major Commercial California Conifers. Research Note No. 33. Northern Calif. Forest Yield Cooperative. Dept. of Forestry and Mgmt., Univ. of Calif., Berkeley. 28 pp.)
Volume Tables
In addition to the profile equations described above, the compiler supports several volume tables. Volume tables generally provide volume based on tree diameter and merch height and use either board feet or cubic feet. The list below includes the currently supported volume tables. Additional volume tables can be added if needed.
Mesavage and Girard Volume Tables
Scribner, Doyle and International 1/4” tables (Mesavage, C., and J. W. Girard. 1946. Tables for estimating board-foot volumei of timber. USDA Forest Servicei, Washington, DC. 94p)
Implemented via equations from Wiant 1986 (Wiant, Jr. H. V. 1986. Formulas for Mesavage and Girard's volume tables. Northern Journal of Applied Forestry 3(3)124.)
Minor’s Pulpwood Tables
Minor, Charles Oscar, "Form class volume tables for use in southern pine pulpwood timber estimating" (1950). LSU Agricultural Experiment Station Reports. 185.
Compiling A Cruise
The standard process for compiling a cruise is:
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