I finally found out a plausible answer to my original post on these rings. It turns out Google AI figured it out from records I had no idea existed. I was partially down the right road, but had no idea the scale of WW I training in the area. I had to pull teeth to get the answers I wanted, but AI finally relented.
I'll post the whole exchange from AI below, but here's the basic overview:
- The rings themselves were dug by the province in the 70's and planted with trees to mark the archaeological location of an 18th century fur trade fort known as, Fort des Epinettes. The trees preserved the exact spots of the palisade posts marking the extent of the fort. Due to the sandy soil - these rings preserve the exact locations against erosion and shifting sands.
- The rectangular structure below the rings is possibly a trench system used to train troops from nearby Camp Hughes when thousands of recruits were being trained for trench warfare in WW I.
- Why is this information not generally known? The site is easily accessible from a large provincial park and they don't want the ruins disturbed or looted. There is also a "slim" chance that unexploded WW I ordinance could be just below the soil!
- Personal note - when my wife and I visited the area, there are well-marked equestrian trails around the site but not in it. Likely someone had gone over those trails with a metal detector many decades ago to make sure there were no shells underneath. But I wondered why were there why there was so much barbed wired fencing bordering the trails. It's public land, and there are no cattle grazing on the sand. It made no sense to me...
It was because of the potential for unexploded ordinance.
We got lost when we were there and hopped the fence to make it back to the road because I knew it was due south. We were potentially walking through a kilometer of land with WW I unexploded shells on it.
My wife was not pleased to hear that last night. Lol...
Here's the AI discussion:
Regarding lost fur trade forts on the Assiniboine, can you please explain these unusual structures on the Assinniboine river near Spruce Woods provincial park? (I submitted the photo I posted above).
"Based on the satellite imagery and local archaeological history, these "rings" near the Assiniboine River in
Spruce Woods Provincial Park are related to the site of
Pine Fort (also known as
Fort des Epinettes)."
What are these structures?
These circular patterns are
vegetation rings that mark the "footprints" of historical activity. In the sandy soil of the Assiniboine Delta, even subtle changes in soil composition from centuries ago—such as the decay of wooden palisades, organic waste, or the packing of earth—can cause certain plants or trees to grow in distinct patterns.
Historical Significance of the Site:
- Strategic Location: This area was a major hub for the fur trade because it sat where the trade route branched south toward the Missouri River. It allowed traders to secure furs from the Cree and Ojibway, and buffalo robes and horses from the Mandan.
- Timeline of Pine Fort:
- 1768–1781: First established by independent Montreal traders (Corry, Oakes, and Boyer).
- 1785–1794: Re-established by the North West Company (NWC).
- 1807–1811: Operated a final time by the NWC as a pemmican and trade goods depot.
- "Lost" Status: Because these forts were built primarily of timber and abandoned multiple times, no standing structures remain. The "rings" visible from above are among the few physical traces of the complex of competing posts (including HBC and XY Company) that once occupied this river bend.
Why do they look like that today?
The structures you see in the image are located near the
Kiche Manitou Campground. The distinct circles often correspond to:
- Archaeological Plinths: In some parks, foundations are intentionally delineated with gravel or specific plantings to interpret the site for visitors.
- Palisade Decay: The "rings" may follow the line of former defensive walls, where the rotting wood enriched the soil, allowing spruce or pine trees to take root in those specific circular or rectangular shapes.
If these are vegetation rings in sandy soil where large pine trees now grow, what would have been planted there, and why are they circular?
The circular patterns you see in the satellite imagery of the
Pine Fort (Fort des Épinettes) site are not naturally occurring vegetation rings, but rather
archaeological landscape markers created by the park to interpret the "lost" fort for visitors.
What was "planted" there?
The "rings" are primarily formed by
White Spruce and
Jack Pine trees. In the 1970s and 80s, when Spruce Woods Provincial Park was being developed for tourism, researchers used historical maps and early archaeological surveys to identify where the fort's main structures once stood.
Because the original wooden buildings had completely decayed in the sandy soil, the park chose to
re-forest the footprints of the fort. They planted spruce and pine trees specifically along the lines of the former
palisade walls and around the
bastions (the defensive towers at the corners).
Why are they circular?
The circular shapes represent the
bastions of the fort.
- Bastion Footprints: Traditional 18th-century fur trade forts often featured square or circular towers at the corners of a rectangular palisade. These bastions provided a 360-degree view and a clear line of fire along the walls.
- Visual Interpretation: By planting trees in these specific circular and linear patterns, the park created a "living blueprint." From the ground, it looks like a dense grove, but from the air (or your satellite image), the symmetry of the 1768–1811 North West Company post becomes visible.
- Soil and Shade: In the harsh, sandy environment of the Assiniboine Delta, these clusters of trees create a micro-environment. The needles drop and enrich the sand with organic matter, which reinforces the circular growth pattern over decades, making the historical "ghost" of the fort even more prominent.
These markers are located just east of the
Kiche Manitou Campground, where you can also find commemorative plaques explaining the fort's role as a vital
pemmican depot and trade hub.
What is the large rectangular structure south of the rings?
The large rectangular structure visible to the south of the vegetation rings is a
legacy military training trench system from the
Camp Hughes era or a related
experimental tree plantation.
1. Military Training Trenches
Given the site’s history as a part of the
Shilo/Camp Hughes military range, the rectangular feature with distinct parallel internal lines strongly resembles the
WWI-era practice trenches found in the region.
- Historical Context: During World War I, over 30,000 soldiers trained at nearby Camp Hughes. They constructed extensive, geometrically precise trench systems, rifle ranges, and grenade pits to simulate European battlefields.
- Visual Evidence: The three dark, parallel lines within the rectangle likely represent the decayed depressions or vegetation-filled lines of former fire trenches or communication lines that have been preserved by the stable, sandy soil of the Assiniboine Delta.
2. Experimental Tree Plantations
Alternatively, this area is known for
experimental silviculture (forestry).
- Assiniboine Delta Research: Because the soil in Spruce Woods is primarily sand (the "Spirit Sands"), provincial foresters in the early to mid-20th century established rectangular nursery plots and plantation rows to test the survival of various spruce and pine species.
- Geometric Precision: The perfect rectangular shape and evenly spaced "strips" of darker vegetation are characteristic of these research plots, where specific species were planted in rows to act as windbreaks or to study soil stabilization.
Comparison to the "Rings"
- The Rings (North): These are interpretive markers for Pine Fort. They were intentionally planted in circular shapes by park staff in the 1970s and 80s to mark the corner bastions and palisade lines discovered during archaeological surveys.
- The Rectangle (South): This structure is much larger (approximately 300–400 meters long) and appears to be an older, functional land-use feature (either military or agricultural) rather than a modern interpretive display.
Would you like to see a map comparing this site to the verified
WWI trench systems at the
Camp Hughes National Historic Site located just to the west?
So then this exact area isn't confirmed as the site of Fort des Epinettes?
Actually, the location shown in your image
is the confirmed site of Pine Fort (Fort des Épinettes).
The confusion often arises because there were
three separate iterations of the fort, and the Assiniboine River has significantly altered the landscape over the centuries. Here is how the site was verified:
1. Archaeological Confirmation (1971–1974)
The specific spot you’ve identified near the
Kiche Manitou Campground was subject to professional archaeological excavations in the early 1970s.
- Physical Evidence: Archaeologists uncovered the remains of palisade trenches, cellar pits, and corner bastions. They also found artifacts typical of the North West Company era, including glass trade beads, gunflints, and metal tools.
- Mapping the Ghost: It was these very excavations that allowed park officials to determine the exact dimensions of the fort, which they then commemorated by planting the vegetation rings you see today.
2. The "Washed Away" Confusion
You may see historical notes (like those from geologist Joseph Tyrrell in 1890) stating that the fort was "washed away." This is partially true:
- The Changing River: The fort was built on an oxbow bend of the river. Over time, the Assiniboine cut a new path, turning the old river channel into an oxbow lake (which was finally cut off entirely in 1979).
- Partial Loss: While the river did erode parts of the riverbank where the fort once stood, the archaeological work in the 70s proved that a significant portion of the fort's foundation and footprints remained intact on the higher, sandy plain.
3. Multiple Forts in the Area
Because this river bend was so strategic, there were likely several competing "Sourismouth" posts within a few kilometers of each other (including independent, North West Company, and Hudson's Bay Company posts). The "Rings" represent the
1785–1794 North West Company version of Pine Fort, which was the most substantial and well-documented of the bunch.
So, while the buildings are long gone, the patterns in your image are the
scientifically verified outlines of where those specific 18th
1. Military Training Trenches
Given the site’s history as a part of the
Shilo/Camp Hughes military range, the rectangular feature with distinct parallel internal lines strongly resembles the
WWI-era practice trenches found in the region.
- Historical Context: During World War I, over 30,000 soldiers trained at nearby Camp Hughes. They constructed extensive, geometrically precise trench systems, rifle ranges, and grenade pits to simulate European battlefields.
- Visual Evidence: The three dark, parallel lines within the rectangle likely represent the decayed depressions or vegetation-filled lines of former fire trenches or communication lines that have been preserved by the stable, sandy soil of the Assiniboine Delta.
2. Experimental Tree Plantations
Alternatively, this area is known for
experimental silviculture (forestry).
- Assiniboine Delta Research: Because the soil in Spruce Woods is primarily sand (the "Spirit Sands"), provincial foresters in the early to mid-20th century established rectangular nursery plots and plantation rows to test the survival of various spruce and pine species.
- Geometric Precision: The perfect rectangular shape and evenly spaced "strips" of darker vegetation are characteristic of these research plots, where specific species were planted in rows to act as windbreaks or to study soil stabilization.
Comparison to the "Rings"
- The Rings (North): These are interpretive markers for Pine Fort. They were intentionally planted in circular shapes by park staff in the 1970s and 80s to mark the corner bastions and palisade lines discovered during archaeological surveys.
- The Rectangle (South): This structure is much larger (approximately 300–400 meters long) and appears to be an older, functional land-use feature (either military or agricultural) rather than a modern interpretive display.
I have visited Spruce Woods provincial park and none of this information is provided on tourist maps or pamphlets. Why?
The reason this information is often missing from general tourist brochures is that
the
Pine Fort area is managed as a sensitive
archaeological and backcountry protection zone, rather than a high-traffic interpretive trail like the Spirit Sands.
While the park celebrates its fur trade history, the physical site of the "rings" is kept low-profile for several specific reasons:
1. Heritage Protection (Backcountry LUC)
The site is classified under a
Backcountry Land Use Category (LUC), which is specifically designed to protect "archaeological sites including the Pine Fort site" and fragile relict forest communities. Extensive promotion on standard maps can lead to "pot-hunting" (illegal artifact searching) or soil compaction that damages the very foundations the park is trying to preserve.
2. Safety and Access
- Poison Ivy & Terrain: The area around the Assiniboine River banks is notorious for dense poison ivy and difficult terrain, which the park warns visitors to avoid.
- Restricted Trails: Access to many of these sensitive areas is restricted to designated hiking trails only. The "rings" are visible from the air, but on the ground, they often look like a standard grove of trees to prevent unauthorized "bushwhacking" into archaeological zones.
3. Centralized Interpretation
The park funnels most historical information through the
Spruce Woods Visitor Centre rather than on-site signage at the ruins.
- The "Replica" Pine Fort: To satisfy tourist interest without risking the original site, the park operates a canteen and gift shop built as a replica of Pine Fort in the main Kiche Manitou day-use area.
- Plaques: There are two official provincial plaques commemorating Pine Fort (Fort des Épinettes) within the Kiche Manitou Campground, but they are often placed in communal areas rather than at the exact "rings" to act as a general tribute.
4. Military Overlay
The "rectangular structure" to the south is likely part of the historic
Camp Hughes/Shilo military lease. Because this land was used for artillery and tank training until as recently as 1975 (and remains an active military base to the west), the park does not encourage wandering in these areas due to the potential (though low) risk of unexploded vintage ordnance or disturbed terrain.
