Detailed (stand level) Forest Inventory

Detailed forest inventory in Minnesota is an individual stand description.  The methods used are generally similar among the various federal, state, and county agencies and private companies. Using a definition similar to that of the Society of American Foresters, stands are stereoscopically delineated using the latest available black-and-white and/or color infrared aerial photos.  Minimum stand sizes range from 1-10 acres.  Individual stands are sampled using a random, systematic, and/or cruiser defined approach and a 10-20 Basal Area Factor (BAF - cross-sectional area of a tree) variable radius plot for merchantable size trees.  A fixed radius plot and general observations are used to characterize regeneration (young trees).  The number of plots allocated to individual stands is largely acreage based but may be influenced by stand heterogeneity (variance).  Data are collected on field sheets or data recorders.  Data on insects, disease, shrubs, and ground cover are largely observational.  Fieldwork is completed primarily by local resource managers, contractors, or employees whose primary responsibility is field inventory. Management prescriptions may or may not be part of the inventory process. 

Stands are identified through a stand/legal description or a stand/compartment numbering system that provides a unique identifier for each stand.  Vegetation descriptors may include the following attributes: cover type/size/density; total volume; total basal area; stand age; site index; species distribution; condition class; understory/type/size/density; volume of trees by species; average diameter by species; insect/disease data by species; shrubs/ground cover; height of main species; and stand origin.  In addition, items concerning significant conditions, operability, topography, timber status, distance to road, physiographic class, soil type, and stand history may be included.  For more information go to: Cooperative Stand Assessment (CSA)

Stand attributes are compiled by hand or electronically and, for the most part, data processing is centralized with the data stored in an ARC/INFO geographic information system (GIS).  Stand summary information and/or individual plot and tree data are stored.  Linkages to other database systems may include other GIS layers.  Most uses of the database involve some sort of planning efforts such as area planning, timber management planning, daily work planning, silvicultural prescriptions, or  allowable cut determination.  In addition, some wildlife analysis may be done with data from the stand inventory as well as other projects such as initial old-growth forest determination.  Local managers are provided with a paper map and printout to access the information.  Computerized attribute and GIS query capability exist at a central location and many local offices.  Spatial data is updated as cultural treatments are applied and through occasional comprehensive re-covertyping of selected areas as needed. 

Source:  Stand Inventory Systems in the Lake States Area.  1994.  Minnesota Department of Natural Resources - Division of Forestry, Resource Assessment Program.  2002 Airport Road, Grand Rapids, MN 55744.  218-327-4449.  37 pp.

Detailed metadata records for forest inventory GIS data sets have been developed for many federal, state, and county agencies.

However, forest inventory metadata have not yet been developed for several northern counties, private companies, or Minnesota's tribal communities.  The following links will take you to a list of GIS coordinators who may be contacted for information regarding their GIS data development activities:
 

Key Terms

Allowable Cut - The amount of timber that may be harvested over a period of time, usually a year 

Spatial Data - Information on the geographic location of features within stand boundaries 

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