GLO ecology observations joined to PLSS context, 1845–1942

Summary

This context layer connects all 61 visually verified GLO ecology records from 1845–1849 and 1942 to exact BLM PLSS township/range geometry. The records match 13 PLSS townships, including the Fox Island townships T34N R13W (South Fox) and T35N R13W (North Fox), as well as the Beaver, Garden, Hog, High, Ojibwa, Trout, Whiskey, Hat, Shoe, and Pismire contexts.

The join is deliberately narrow. Each page retains its own source record, island, date, volume page, and page ID, then receives the matching BLM PLSS feature reference. The output does not copy geometry into the observation record and does not turn a page-bounded survey description into a present-day forest, soil, habitat, parcel, or ownership polygon.

What the field notes record

The 61 joined pages are not abstract metadata; each is a visually verified reading of a General Land Office surveyor’s terrain, timber, and shoreline notes for a specific island, cross-checked against the scanned page image.¹ Across the 1845-1849 survey, the most frequently reported tree names are cedar (43 pages), fir (39), sugar maple (38), beech (21), white birch (20), spruce (19), aspen and tamarack (18 each), and hemlock (17), with pine, maple, ironwood, hazel, and several other species recorded less often. Beaver Island itself accounts for 21 of the 57 tree-bearing 1845-1849 pages and the widest species list — including white pine, hemlock, elm, and cherry alongside the more common cedar and maple — while smaller islands such as Hat Island and Gull Island are represented by only one or two species each.¹

Individual pages carry specific, dated description. The 1849 Hat Island page records an island “about 6 feet high and nearly level, mostly gravel and small stone washed up by lake swells,” with “brushy cedar growth … 10-30 feet high,” part of which “has been burned.”² Nearly a century later, the 1942 survey of Shoe Island — one of only four modern-era pages in this join, covering Shoe and Pismire Islands — found no timber and “no indication of former timber,” describing instead “scattered weeds, grass, and small willows” on a low gravel-and-boulder island sloping from about six feet above Lake Michigan on the northwest to about two feet at the southeast point.³ These are page-bounded readings of specific survey visits, not a claim that any island’s vegetation was uniform or unchanged between readings.

What the section context means

The held section layer makes it possible to see which island-intersected PLSS sections are available inside each matched township. Those section numbers are reported as candidate spatial context only. The retained ecology records usually identify a township/range and a page-bounded survey operation, not a single section. Consequently, the artifact marks every record assignment_status: not_resolved_from_source_record rather than guessing from page order or nearby text.

This distinction matters most for combined or fractional-island descriptions: the Garden/Hog page remains a combined source record, and the same township can contain records for multiple islands. T40N R8W also has two returned township geometry features in the BLM response; both are preserved in the context layer.

Use in maps and later joins

The PLSS township geometry is now a safe cartographic frame for showing where a GLO observation belongs at township/range scale. A map may symbolize records by island, year, source page, tree terms, shore material, wetlands, disturbance, or bird observation and link back to the evidence image. It should not draw an ecology boundary around the township or imply that every candidate section shares the page’s reported conditions.

The layer can support a later, higher-resolution pass over GLO pages that explicitly state section numbers. Such records can be joined to PLSS sections only when the section wording and page evidence are retained together. Current soil, forest-inventory, NLCD, and MNFI context remains at its own documented scale; this artifact does not claim EO-to-pixel, stand-to-page, or soil-series overlap.

The current explicit-section companion implements that rule for 31 claims: 30 exact PLSS matches and one documented missing-geometry case, represented by 25 unique map polygons.

Added 3 August 2026. Recent changes