The Expanding Circle Problem: Why Fixed-Camp Survival Fails Faster Than People Expect
Most survival discussions focus on skills: plant identification, shelter building, fire craft. Those matter—but they distract from the real limiter in temperate forests:
energy economics.
If you camp in one place and forage outward day after day, you run into a hard constraint that no amount of skill can overcome. I call it the expanding circle problem. It killed hundred of thousands of Japanese soldiers on remote islands in WW2.
The simple observation
When I camp in the forest, I notice something unavoidable:
Every day, I have to walk farther to find food, fuel and shelter materials.
Nearby resources are stripped first. Then I range a little wider. Then wider again. What changes isn’t just distance—it’s cost.
Walking burns calories. Searching burns calories. Processing food burns calories. As the circle expands, cost rises faster than yield.
At some point, you cross from profit to loss.
Survival vs scale
Survival theory often says:
“A trained individual can live off the land.”
That is conditionally true—but only when these assumptions hold:
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very small numbers (1–2 people)
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high mobility
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short time horizons
rich resources
excellent training
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no enforced static position
A fixed camp violates almost all of these. This is what killed so many Japanese soldiers who where told to live off the land in the Pacific.
Once you stay put, survival becomes a patch-depletion problem, not a skills problem.
The energy math (simplified)
Daily net energy looks like this:
Net calories = food gained − (walking cost + processing cost)
Break-even happens when:
Food gained = 2 × distance × walking cost + overhead
Typical off-trail walking in forest terrain costs on the order of 80–140 kcal per km. Processing, water, fire, and friction add 200–500 kcal per day depending on conditions.
That means distance matters a lot.
September vs October vs December (interior BC Canada example)
September
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Some high-calorie plant foods (mainly berries)
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Lower cold penalty
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Lower processing overhead
If you’re lucky and near productive patches, you can be in the black for several days—sometimes a week or more—if the radius grows slowly. I assume you are an expert at plant identification.
October
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Berry availability collapses
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Cold, rain, and mud raise costs
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Remaining patches are sparse
In a fixed camp, most people cross into net negative energy in ~3–7 days. Not because they suddenly “fail,” but because the circle expands faster than calories can be brought back.
December
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Plant calories are negligible
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Processing and cold costs dominate
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Break-even often never occurs at all
You start in deficit and stay there.
The real lesson for survival planning
The most important survival skill is not plant ID or fire-starting.
It is understanding when a strategy is structurally doomed.
Fixed-camp, plant-based foraging in temperate forests works briefly in late summer. It fails quickly in autumn. It fails immediately in winter.
Historically, people who lived in these environments succeeded by:
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moving frequently,
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storing food,
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fishing or hunting high-return calories,
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or combining all three.
The expanding circle problem explains why.
Bottom line
Loosely speaking, when foraging in the wild:
You may be in the black for a few days to about a week.
After that, unless something changes, you are in the red.
That’s not pessimism.
That’s arithmetic.
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