(41C) On-Site Determinations of stand density & growth w ⁄ …

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An excerpt from A User's Guide for On-Site Determinations of stand density & growth with a Programmable Calculator, Forest Research Lab, College of Forestry, Oregon State University, SP-11, April 1985, 25 pages

Introduction
To help foresters quickly determine stand growth and density in the field, we have developed two programs, FIXP for fixed plots and VARP for variable-radius plots, to be run on a hand-held calculator convenient to use on site. We believe the programs will save both inventory and office computation time. The necessary field data are relatively easy to obtain. You supply tree height, diameter, radial growth, and a measure of stand density. The appropriate program quickly summarizes the data, providing estimates of the current growth in cubic volume, basal area, and diameter, and of number of trees, basal area, and cubic volume per acre. Because estimates can be calculated in the field, questions they may raise can be immediately resolved by observation or additional measurement.

The programs apply to any species for which you have volume equations. We provide equations from Brackett (1973) for Douglas-fir, Sitka spruce, ponderosa pine, alder, big-leaf maple, and aspen, and from Chambers and Foltz (1979) for western hemlock. The programs allow insertion of local volume equations or those with merchantability standards.

We emphasize that the programs are designed for stand examination and analysis in the field. They do not replace powerful, computer-based stand simulators that estimate and project stand growth under different densities and treatments. However, they can be used with such simulators and with site-specific information to verify growth estimates, test thinning strategies, and calibrate growth models to specific stands.

How the Programs Work
 Tarif-Tree Section
 Stand-Table Section
  Tree Volume
  Basal-Area Growth
  Volume Growth
 Summation by Species or Sets
 VARP / FIXP Flowchart
User's Guide for VARP / FIXP
 Getting Started
  The programmable calculator we used was a Hewlett-Packard 41-C with a quad calculator
  memory module (equivalent to four standard memory modules). The newer HP-41 CV
  has the same amount of memory built in. Three standard memory modules in an
  HP-41C can also be used.
 Running Procedure
 Sample Run: VARP
 Sample Run: FIXP

Using Stand Estimates in Prescriptions for Silviculture
 Contrasting Diameter, Basal-Area, and Cubic-Volume Growth
 Determining When to Harvest
 Evaluating the Effects of Cutting
 Calibrating Growth Models

Literature Cited

Appendices
 Tarif-Number (TN) Equation w/ program listing
 Cubic-Volume Total-Stem (CVTS) Equation w/ program listing
 How to Change Volume Equations w/ program listing
 Species-Specific Equations w/ program listing
 Data Register Assignments for VARP and FIXP
 Program Listing: VARP
 Program Listing: FIXP
 Notation

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[Ángel Martin]

Very nice, thanks for sharing!