WestProPlus: a stochastic spreadsheet program for the management of all-aged Douglas-fir–hemlock forests in the Pacific Northwest.
| Authors: | Jingjing Liang, Joseph Buongiorno, Robert Monserud |
| Year: | 2006 |
| Type: | General Technical Report |
| Station: | Pacific Northwest Research Station |
| DOI: | https://doi.org/10.2737/PNW-GTR-674 |
| Source: | Gen. Tech. Rep. PNW-GTR-674. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 42 p |
Abstract
WestProPlus is an add-in program developed to work with Microsoft Excel to simulate the growth and management of all-aged Douglas-fir–western hemlock (Pseudotsuga menziesii (Mirb.) Franco–Tsuga heterophylla (Raf.) Sarg.) stands in Oregon and Washington. Its built-in growth model was calibrated from 2,706 permanent plots in the Douglas-fir–western hemlock forest type in Oregon and Washington. Stands are described by the number of trees per acre in each of nineteen 2-in diameter classes in four species groups: Douglas-fir, other shade intolerant species, western hemlock, and other shade-tolerant species.WestProPlus allows managers to predict stand development by year and for many decades from a specific initial state. The simulations can be stochastic or deterministic. The stochastic simulations are based on bootstrapping of the observed errors in models of stand growth, timber prices, and interest rate. When used in stochastic simulations, this bootstrap technique simulates random variables by sampling randomly (with replacement) from actual observations of the variable, rather than from an assumed distribution. Users can choose cutting regimes by specifying the interval between harvests (cutting cycle) and a target distribution of trees remaining after harvest. A target distribution can be a reverse-J-shaped distribution or any other desired distribution. Diameter limit cuts can also be simulated. Tabulated and graphic results show diameter distributions, basal area, volumes by log grade, income, net present value, and indices of stand diversity by species and size.
This manual documents the program installation and activation, provides suggestions for working with Excel, and gives background information on West-ProPlus's models. It offers a comprehensive tutorial in the form of two practical examples that explain how to start the program, enter simulation data, execute a simulation, compare simulations, and plot summary statistics.