Your Fantasy World is Running Out of Wood

Scientific concepts, discoveries, and nature phenomena

Mass transport & logistics constraints

• Firewood is bulky/heavy “pure bulk” and expensive to transport over distance.
• Grain is dense enough to ship in bulk across oceans, enabling cities to obtain food far from production areas.
• These transport cost differences create separate “fuel vs food” supply geographies.

Hydrodynamics of rivers enabling free downhill transport

• Dropping logs/rafts into a river uses the current to move fuel downhill “for free.”
• This creates a directional asymmetry:
  • Fuel is cheap downstream
  • Fuel is costly upstream
• Historical examples include:
  • Forests/wood floated to shipyards
  • Rafts carrying wood along rivers

Thermal energy scarcity (“heat as a limiter”)

• Cities require two main supplies: food and heat.
• Firewood supply constrains population and survival, especially during winter.
• The key idea is a “fuel ceiling”:
  • Heat-intensive industries can only scale as far as available fuel allows.

Ecology & land-use succession after deforestation

• After forests are stripped, the next available fuel often becomes what grows where trees were removed:
  • Peat in bog environments
  • Dung and crop stubble in treeless steppe areas
• Loss of forest cover can increase erosion, and may affect:
  • River siltation/flooding
  • Downstream agriculture

Alternative fuels derived from wood

• Charcoal production via slow, oxygen-limited burning (a pyrolysis-like process):
  • Produces light, hard, cleaner carbon compared with raw wood
  • Requires substantial wood input: 5–7 tons of wood → 1 ton of charcoal
• Charcoal’s improved transportability and carbon purity make it useful for some metalworking, but it remains “regionally locked” due to production bulk.

Thermochemistry and metallurgy constraints

• Raw wood is inadequate for iron smelting because it is:
  • Too dirty (impurities)
  • Too weak structurally to meet furnace requirements
• Charcoal enables iron smelting by providing:
  • Sufficiently pure carbon to reduce ore effectively
  • Appropriate mechanical properties for furnace stacks and draft conditions

Carbon history & fossil fuels

• Coal is framed as fossilized ancient biomass: “concentrated sunlight over long timescales.”
• Coal breaks local fuel limitations because it is:
  • Dense and valuable
  • Transportable by sea
  • Stable (does not rot)

Environmental chemistry & public health impacts of coal

Coal introduces several risks:

• Mine gases
  • Carbon monoxide
  • Methane ignition/explosions (“firedamp”)
• Acid rain formation from sulfur
  • Sulfur → atmospheric reactions → acid rain → damage to buildings/crops
• Indoor air pollution
  • Smoke/fumes spread into homes with poor ventilation
• Toxic inhalation outcomes
  • Coal miners’ “black lung” (coal workers’ pneumoconiosis-like risk)
• Metallurgical effects
  • Coal-derived impurities/traces can make iron more brittle

Process engineering: converting coal to coke

• Coke is produced by heating coal in an oxygen-deprived environment:
  • Volatile/impure components escape
  • Leaves a higher-purity carbon fuel
• Coke is described as a key step enabling Britain’s industrial breakthrough in iron and engines.

Historical technological dependency loops (“self-feeding supply chains”)

• Britain’s success is attributed to building a continuous feedback chain:
  • coal → iron → engines → more coal demand

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Methodology / step-by-step procedure (from the worksheet)

Step 1: Fuel sources

• Mark all fuel sources your world has (e.g., forests, peat/bogs, coal).
• Decide forest management:
  • Coppicing vs clear-cutting
• Place heavy, fuel-hungry industries near the fuel:
  • ironworks, glasshouses, salt pans near trees/fuel

Step 2: Fuel radius

• Draw a fuel transport radius for each source.
• Extend radius downhill along rivers where rafting is possible.
• Use relative value to set carry limits:
  • timber < charcoal < coal
  • (Charcoal is worth carrying farther than raw timber; coal farther than both.)

Step 3: Heat tax

• Optionally set a heat tax so citizens pay for permission to keep hearths lit.
• Tax revenue supports some system or institution (cost and funding are user-defined).

Step 4: “The hook” (story generation via mapping constraints)

Use the map to generate plot drivers:

• A city can collapse in one winter.
• A “forest lord” can outgain political rivals by controlling fuel.
• Fuel embargoes can cause strangulation without open war.
• Whoever finds coal first can win an arms race.

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Researchers or sources featured

• Abraham Darby (introduced coke, cited as doing so in 1709)
• No other specific individual researchers are named in the subtitles beyond Darby.