Cooperative Stand Assessment (CSA) Codes and Terminology

Like other applied sciences, Forestry has its own terminology used to describe complex concepts. Below are definitions of key terms used in CSA stand descriptions.

Stand ID: A unique identifier for a stand in the statewide CSA database, consisting of:

  • "t"
  • township
  • range
  • range direction
  • owner code
  • section
  • type number (a unique 4-digit numeric identifier for a stand within a township)

For example, a stand in township 135, range 31 west, on state ownership (code 1), in section 16, with a type number of 32, would be represented as: "t"+135+31+"w"+1+16+0032 = t13531w1160032

DBH: (Diameter at Breast Height). A conventional measure of tree diameter, taken outside the bark at a point 4.5 feet above ground.

Average Diameter Class: This is an average size expression for the trees populating a stand. The measurement is the average of diameter at breast height (DBH) for trees throughout the stand. Values for average diameter classes can range anywhere from under one inch for young saplings, to over 25 inches for large, mature trees.

Basal Area Per Acre: Another measure of how well a stand is stocked, basal area equals the sum of the cross-sectional area of all trees, measured at DBH, and averaged across the acreage of the stand.

Volume: Cords and board feet are conventional units of wood volume.  A cord is a stack of logs measuring 4 feet wide by 4 feet high by 8 feet long; a board foot is a measure of sawn lumber equivalent to a piece 1 foot wide by 1 foot long by 1 inch thick. For rough comparison purposes, one cord approximates 500 board feet. Typically for trees between 5" and 14.9" in diameter, volume is measured in cords, for trees 15" and larger, volume is measured in board feet.  Volume is often expressed on a per acre basis.

Rotation Age: The age at which a stand would normally be harvested to capture maximum productivity or volume from the site it is growing on.

Cover Type: These are general descriptive terms for the overall contents of stands. The terms "offsite" and "stagnant" as used in cover type names, signify lower productivity. The cover type designations used in CSA are listed below.

  • Ash
  • Willow
  • Lowland Hardwoods
  • Aspen
  • Birch
  • Balm of Gilead
  • Cottonwood
  • Northern Hardwoods
  • Walnut
  • Oak
  • Central Hardwoods
  • White Pine
  • Norway Pine
  • Jack Pine
  • Scotch Pine
  • White Spruce
  • Balsam Fir
  • Black Spruce, Lowland
  • Tamarack
  • White Cedar
  • Black Spruce, Upland
  • Stagnant Spruce (site index 22 or lower)
  • Stagnant Tamarack (site index 22 or lower)
  • Stagnant Cedar (site index 22 or lower)
  • Offsite Aspen (site index 34 or lower)
  • Offsite Oak (site index 34 or lower)
  • Red Cedar
  • Cutover Area
  • Lowland Grass
  • Lowland Brush
  • Upland Brush
  • Duff
  • Moss
  • Agriculture
  • Industrial Development
  • Recreational Development
  • Roads
  • Rock Outcrop
  • Permanent Water
  • Non-Permanent Water
  • Marsh
  • Muskeg

Tree Species: The following is a list of Minnesota tree species.

  • Black ash
  • American elm
  • Silver maple
  • Red elm
  • Rock elm
  • Willow
  • Trembling aspen
  • Paper birch
  • Balsam poplar
  • Cottonwood
  • Bigtooth aspen
  • Hybrid poplar
  • Red maple
  • Sugar maple
  • Basswood
  • Yellow birch
  • Walnut
  • Butternut
  • Cherry
  • Buckeye
  • Northern red oak
  • Black oak
  • Northern pin oak
  • White oak
  • Bur oak
  • White ash
  • Green ash
  • Bitternut hickory
  • Shagbark hickory
  • Hackberry
  • Box elder
  • White pine
  • Norway pine
  • Jack pine
  • Scotch pine
  • Ponderosa pine
  • Austrian pine
  • White spruce
  • Balsam fir
  • Colorado spruce
  • Norway spruce
  • Black Hills spruce
  • Black spruce
  • Larch (Tamarack)
  • European larch
  • Japanese larch
  • Siberian larch
  • Northern white-cedar
  • Eastern red-cedar
  • Hemlock
  • Douglas fir
  • Locust
  • Ironwood
  • River birch
  • Blue beech

Condition Class: This expresses the situation of the stand with respect to the rotation age of its cover types. Condition classes used in the CSA inventory program are listed below.

Not stocked.

Stand does not contain the minimum density of regeneration.

High risk:

Unlikely to survive 5 years without major volume loss.


At or beyond rotation age but not at high risk.


Between 10 years old and rotation age.


Less than 10 years old.

Extended rotation:

Specially designated for longer than normal rotation period.

Management Status: This term describes how the stand will be handled with respect to timber management. Management status classes used in CSA are listed below.

Normal timber harvesting allowed

Restricted timber harvesting allowed

No timber harvesting allowed

Extended rotation forest

Designated old growth stand

Potential or future old growth

Under development; e.g., stand is currently a timber sale.

Physiographic Class: This term expresses the condition of the stand with respect to water drainage through the soil, which has a strong effect on species suitability, productivity, and management choices. Physiographic classes used in CSA are listed below.


Very dry; water drains through quickly.


Moderately dry; water retained for a short period of time.


Optimum water retention; offers favorable management.


Soil retains water for long periods of time, will drain.


Soil remains saturated year round.

Site Index: This is a conventional forestry measure of the timber-growing quality of a site. It represents the average height attained by a tree of a particular species at 50 years of age.

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