The Expanding Circle Problem: Why Fixed-Camp Survival Breaks Down
Hundreds of thousands of Japanese soldiers starved to death on Pacific islands (Rabaul, Marshalls, Carolines, Gilberts, New Guinea & Solomons) when the survival textbooks say you can live off the land.
A major constraint in temperate forests is energy economics.
If you camp in one place and forage outward each day, you face an unavoidable problem:
Every day, you must walk farther to get the same food.
Nearby resources are depleted first. Then the foraging radius expands. Distance increases, and so does cost.
At some point, calories spent exceed calories gained. No amount of skill changes that arithmetic.
Survival doesn’t scale at a fixed camp
“Living off the land” can work for:
-
one person,
-
short durations,
expert survivalists,
-
high mobility.
A fixed camp breaks those assumptions. Once you stop moving camp, survival becomes a patch-depletion problem, not a bushcraft problem.
The simple energy math
Daily net energy is:
Food gained − (walking cost + processing cost)
Off-trail walking typically costs ~80–140 kcal per km. Firewood, water, prep, and friction add 200–500 kcal/day, more as it gets colder.
As the radius grows, cost rises steadily. Yield usually does not.
That’s the expanding circle problem.
Seasonal reality (interior BC Canada example)
September
Berries may still provide meaningful calories. With luck, net deficit in ~7–12 days..
October
Berry availability drops, cold and wet raise costs, patches are sparse. In a fixed camp, most people cross into net deficit in ~3–7 days.
December
Plant calories are negligible. You start in deficit and stay there.
The takeaway
This is not about toughness or mindset. It’s physics plus biology.
For a fixed camp relying on wild plants in temperate forests:
You may be in the black for a few days to about a week.
After that, unless something changes, you are in the red.
Historically, people solved this by moving camp, storing food, or using high-return calories (fish, game). The expanding circle explains why they had to.
