A living city, in numbers
Make room for trees.
Account for the water.
Explore two connections behind the book’s urban design proposals: more canopy needs water; growing media adds weight.
Educational scenarios from the published books · assumptions you can inspect
What does a larger canopy require?
Only the proposed cover changes. The existing canopy and planning area stay fixed.
Planning assumptions
Book defaults are illustrative. Use a consistent mapped boundary and locally supported demand factor for a site-specific scenario.
Moving from 21% to 35% adds 14 percentage points of cover across 250,000 acres.
How much does saturated growing media weigh?
Saturated density already includes the water held in the media.
30 m³ × 1,600 kg/m³ ÷ 1,000 = 48 tonnes
Media only. The container, tree, people and other loads belong in a separate structural inventory.
How the models work · sources & limits
Canopy and water
Additional canopy = planning area × (proposed cover − existing cover) ÷ 100.
Gross additional annual demand = additional canopy × annual water factor.
The default scenario uses 250,000 acres, 21% existing canopy and a factor of 1.74 acre-feet per canopy-acre per year. Targets of 32%, 35% and 40% give 47,850, 60,900 and 82,650 acre-feet per year respectively.
The book’s separate 105-square-mile strategic network equals 67,200 acres. It has a different boundary from the citywide canopy scenario above.
Gardens of Earth, Volume II, Chapter 34, “The Managed Urban Forest,” section “Canopy Targets and the Water Ledger”; Chapter 36, “The Biotic Pump Hypothesis,” section “The Humidity Ledger.” Published Kindle edition, October 2026.
Root-cell media
Media mass (metric tonnes) = volume (m³) × saturated bulk density (kg/m³) ÷ 1,000.
The book’s worked example uses 30 m³ and an assumed 1,600 kg/m³, yielding 48 metric tonnes. Water is already included in the saturated density.
Gardens of Earth, Volume I, Chapter 21, “The Hydroseismic City,” section “Saturated Media Is Seismic Mass”; published paperback page 183.
Scope of this prototype
These transparent calculations explore proposed biourban systems. Cooling, rainfall effects, engineering capacity, net irrigation, costs and water self-sufficiency require additional evidence and separate models. User-entered values are hypothetical scenarios.