Stand Visualization System

SVS logo
A product of the USDA Forest Service, Pacific Northwest Research Station

Send comments to the developer, Bob McGaughey

SVS renders perspective, overhead, and profile views of a stand.

SVS allows users to define the color, crown shape, and overall growth form for each species.

SVS allows you to simulate treatments by marking individual trees or using marking or thinning rules to designate cut and leave trees.

The Stand Visualization System (SVS) generates graphic images depicting stand conditions represented by a list of individual stand components, e.g., trees, shrubs, and down material using detailed geometric models of individual trees and other stand components. The images produced by SVS, while abstract, provide a readily understood representation of stand conditions and help communicate silvicultural treatments and forest management alternatives to a variety of audiences. SVS provides the following capabilities:

display overhead, profile and perspective views of a stand;

differentiate between stand components using different plant forms, colors, or other types of marking as specified by users;

provide a mechanism that allows users to define plant growth form, stem color, and foliage colors based on species, growth form, and plant position within the canopy;

provide tabular and graphical summaries of information represented in a stand image;

facilitate the design of silvicultural treatments by allowing users to select individual stand components and specify treatments; and

display information describing individual stand components as they are selected by the user.

A data conversion program, FVS2SVS, links SVS to the Forest Vegetation Simulator (FVS) to provide stand growth modeling and visualization capabilities for most geographic regions in the U.S.

The SVS software is currently used by a wide variety of users in federal agencies within the U.S., private industry, academia, and research organizations.

Data Requirements

SVS requires two primary types of data: a list of stand components and plant form definitions. The stand component list describes the species, size and location of each component in a stand. Plant form definitions describe the appearance of each species and, optionally, the appearance of individuals exhibiting different growth forms within a species.

The following parameters describe each stand component:

Species code	End diameter	Crown radius 4
Plant class	Crown radius 1	Crown ratio 4
Crown class	Crown ratio 1	Expansion factor
Plant status	Crown radius 2	Marking status
Diameter	Crown ratio 2	X
Height	Crown radius 3	Y
Felling angle	Crown ratio 3	Elevation

The simplest input suitable for use in SVS consists of a simple stand table describing the species, dbh, height, crown ratio, and density of trees in a stand. The included TBL2SVS utility, converts such stand table input into a list of individual components.

Plant Form Definitions

Users define the appearance of each species represented in a component list using a plant form definition. Form definitions describe the overall growth form; geometry and number of branches or leaves; and color of the stem, branches and foliage. SVS provides a "tree designer" to help users develop form definitions for the species and growth forms in their area. SVS uses the species identifier as the primary link between the component list and the plant form definitions. However, two additional parameters, tree class and crown class, can be used to distinguish individuals within a species. Interpretation and use of these two parameters is under the complete control of the user. SVS reserves the value of 99 for the tree class and crown class to represent a "wild-card" value.

Designing Silvicultural Treatments with SVS

SVS allows users to create stand treatments by marking individual trees or groups of trees on either the perspective or overhead displays. Marking rules can be used to select trees based on their attributes. The marking dialog lets users develop silvicultural prescriptions by specifying the desired characteristics for the residual stand.

Computer System Requirements

SVS is designed for personal computers running Windows 9X, 2000, XP and NT (version 3.51+). There is a DOS version of SVS available but it is no longer supported.

This page was last updated on September 27, 2001 by Diane Smith