How to read the historical vegetation map

The decision this helps with

Is the mapped community a plausible reference for this land?

Michigan’s original General Land Office surveys left a remarkable record of trees, wetlands, openings, and landscape conditions before widespread logging and agricultural conversion. The map can help a landowner ask whether an oak opening, wet prairie, beech-maple forest, conifer swamp, or another community is a useful historical reference. It cannot establish that a particular acre had an exact species list or that the same community can be restored there today.

From map to field

Compare, measure and prepare a field packet

Compare places the historical map beside Esri World Imagery with an adjustable divider. The imagery is modern context with varying capture dates, not a current vegetation inventory. The comparison and historical opacity are included in shared view links.

Sketch offers a boundary polygon, a north-aligned rectangle, a circle and a distance line. Click or tap the map, or use the keyboard-accessible Add map center control. Rectangles use two opposite corners; circles use a center and an edge. Area updates in acres while drawing, and the result stays on the map after closing the sketch panel.

Distances use great-circle segments on a sphere; areas use a spherical polygon approximation. Circles are approximated with 128 points at equal ground distance from the center. Measurements omit slope, canopy height and survey corrections. These sketches are for orientation, not legal boundaries, parcel acreage or treatment specifications.

Select a vegetation type and open Field packet to capture the loaded view, its extent, a visible-type legend, source citation and field-check questions. Add private notes, then print or save a PDF through your browser, or download a map PNG with credits. The legend lists types in the view; it does not calculate their acreage inside your sketch. Any statewide acreage is labeled separately.

Measurement sketches and notes remain in the current page and are not included in the share link or analytics. Exports can reveal a location and any notes you choose to include, so review the packet before sharing it.

Source lineage

Three layers of evidence and interpretation

Primary source: Comer et al. (1995), Michigan’s Presettlement Vegetation, as Interpreted from the General Land Office Surveys 1816–1856, MNFI Report 1995-006.

Read the scale honestly

What the Atlas cannot tell you

MNFI compiled the map on USGS 7.5-minute sheets at approximately 1:24,000 or 1:25,000. Its report says the smallest wetlands included were typically about 15 to 20 acres. Boundaries are interpreted, and the underlying surveys were not designed as a scientific vegetation sample.

• It is not a legal boundary, wetland delineation, or property survey.
• It does not show current vegetation, condition, ownership, or access.
• It cannot identify an exact restoration target for a small parcel.
• Witness-tree choice was biased toward trees useful for marking corners, and historical common names can be uncertain.
• The viewer renders the vegetation interpretation; some disturbance and wetland-grade information described by the source is not represented as a separate layer.

Area calculation

Why the percentages are firmer than the acres

The viewer’s statewide area table sums spherical polygon areas from the web-map tiles. Before summing, each buffered tile feature is clipped to that tile’s core so neighboring buffer geometry is counted once. The mapped fabric totals approximately 37.2 million acres.

The acres remain approximate because the source boundaries are interpretations, the fabric includes some shoreline communities, and tiling creates small edge effects. Use relative composition to compare mapped types at statewide scale. Do not treat the statewide total or a map click as surveyed parcel acreage.

Field-check protocol

Five checks before the map guides work

1. Locate the historical pattern. Record all mapped types near the property, not only the polygon under one point.
2. Read soils and landform. Check drainage, texture, slope, aspect, and position in the surrounding terrain.
3. Check hydrology. Look for altered drainage, ditches, impoundments, seasonal saturation, and wetland evidence.
4. Look for living evidence. Note remnant trees, understory regeneration, ground-layer plants, invasives, and signs of past fire or land use.
5. Set a realistic next condition. Balance the historical reference with current constraints, landowner goals, safety, permits, cost, and the work the site can actually hold.

This sequence produces a hypothesis for a site visit. It does not replace a current inventory, survey, delineation, burn plan, or site-specific management plan.

Citation guidance

Credit the source and the web work separately

The source’s requested digital-map citation

Comer, P.J., D.A. Albert, H.A. Wells, B.L. Hart, J.B. Raab, D.L. Price, D.M. Kashian, R.A. Corner, and D.W. Schuen (map interpretation); T.R. Leibfreid, M.B. Austin, C.J. DeLain, L. Prange-Gregory, L.J. Scrimger, K.M. Korroch, and J.G. Spitzley (digital map production). 1995. Michigan’s Presettlement Vegetation, as Interpreted from the General Land Office Surveys 1816–1856. Michigan Natural Features Inventory, Lansing, Michigan. Digital map. The accompanying methods report is MNFI Report 1995-006.

For this viewer and its editorial cartography

Baird Forestry. 2026. Michigan Historical Vegetation Atlas (c. 1800). Web implementation of Comer et al. (1995), method version 1.0. https://bairdforestry.com/tools/mnfi-view. Include your access date.

This citation guidance does not grant a new license for the underlying source data. Check the source holder’s current reuse terms before redistributing data or derived files.