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.
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.
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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.