Companion Graphic No. 03
Four materials. Forty-five years. Every price spike, every tariff, every trade war, every promotion program — laid on the same index so you can see which interventions favoured which material and when. The index is 100 in 1982 for all four. A 15-year-old should be able to read this.
All four materials are set to 100 in 1982. A reading of 250 means the price is 2.5× what it was in 1982. This lets you compare materials fairly — their actual dollar prices are very different, but the index shows movement.
Lumber is heavily traded across borders and highly sensitive to tariff events — particularly the five US–Canada "lumber wars" since 1982. Housing demand multiplies the effect. The 2021 spike (400%+) was COVID renovation demand meeting a Canada tariff.
The 2018 Section 232 tariffs added 25% on steel and 10% on aluminium. Prices spiked. At the same moment, USDA mass-timber promotion funding was already running (since 2015). The competing materials got more expensive; the promotion apparatus was ready.
Cement is globally distributed, energy-intensive but not subject to major trade wars. It absorbs energy price spikes (1973, 1979, 2022) but has no comparable promotion apparatus. Its flatness is partly real, partly a reflection of policy neglect.
These are the dates when federal money and code changes built the market infrastructure for mass timber. They don't move the price line directly — they shape the demand baseline the next price spike will hit.
Every timber price spike is also a carbon accounting event. Higher prices accelerate harvest. The three DRL liabilities — SOC efflux, EOL methane, foregone sequestration — all increase with harvest rate. The financial incentive and the carbon liability move together.