The Duluth Forest Inventory classification scheme followed Minnesota DNR Cooperative
Stand Assessment (CSA) conventions except for one important difference:
While their minimum mapping unit is five acres, stands as small as .2 acres
were mapped for this project.
The Minnesota DNR detailed explanation of CSA can be found here: http://www.ra.dnr.state.mn.us/tp/csa_doc.html
Here is a bit of information, taken from their site, which gives some background on the CSA:
Background
Timber Harvest Plans is based on Cooperative Stand Assessment (CSA), the forest stand mapping and information system used by the Minnesota Department of Natural Resources to inventory the approximately 5 million acres (7800 sq. mi.) owned and administered by the state.
At its origin in 1952, CSA was based on pencil-drawn land use maps and a computer-punchcard database. The system has matured into an Arc/Info geographic information system (GIS) database accessible online by DNR forest managers.
A forest stand is a group of trees uniform enough in composition to be managed as a unit. CSA maps the boundaries and tabulates the contents of all forest stands 5 acres and larger on state-owned land. Stand boundaries are drawn by interpretation of aerial photographs. All other stand data are collected in the field on plots established within each stand; boundaries may be redrawn at the time of field data collection.
Whenever a cultural treatment such as cutting, thinning, planting or seeding is carried out in a stand, the stand's attributes are altered to reflect what has happened. Local forest managers submit their alterations to the CSA database on a regular schedule so that the entire database remains current.
Stand maps and databases are periodically reviewed to assess the need for comprehensive remapping and new data collection.
The 43 Cover Types used for this inventory are listed below. Some of the species have example pictures. Position the cursor over the name and click.
01 - Ash
06 - Willow
09 - Lowland Hardwoods
12 - Aspen
13 - Birch
14 - Balm of Gilead
15 - Cottonwood
20 - Northern Hardwoods
25 - Walnut
30 - Oak
40 - Central Hardwoods
51 - White Pine
52 - Norway Pine
53 - Jack Pine
54 - Scotch Pine
61 - White Spruce
62 - Balsam Fir
71 - Black Spruce, Lowland
72 - Tamarack
73 - White Cedar
74 - Black Spruce, Upland
75 - Stagnant Spruce (SI 22 or lower)
76 - Stagnant Tamarack (SI 22 or lower)
77 - Stagnant Cedar (SI 22 or lower)
78 - Offsite Apsen (SI 34 or lower)
79 - Offsite Oak (SI 34 or lower)
81 - Red Cedar
82 - Cutover Area
83 - Lowland Grass
84 - Upland Grass
85 - Lowland Brush
86 - Upland Brush
87 - Duff
88 - Moss
91 - Agriculture
92 - Industrial Development
93 - Recreational Development
94 - Roads
95 - Rock Outcrop
96 - Permanent Water
97 - Non-Permanent Water
98 - Marsh
99 - Muskeg