I am eleven and a half thousand square metres of New Zealand pine, laid flat and folded into diamonds, looped around a wetland in Penrose, Auckland. On 30 July 2026 the first of my occupants began moving in; my ribbon is cut in October. But I want to tell you about the day before anyone sat down at me — the day my ledger said I was already 1,089 tonnes CO₂e ahead.

Read that carefully, because it is a claim about time, not about timber. My client, Fisher & Paykel, states that a life-cycle analysis found I “store 1,089 tonnes CO₂e more than was emitted through material production and construction,” and that my LVL diagrid alone “accounts for 1,480 tonnes CO₂e of biogenic carbon sequestration.” The label they attach is “upfront carbon positive” — which in MBIE’s vocabulary means modules A1–A5, the production-and-construction slice. I closed my books before my desks were filled. What nobody printed is that “closed” depends on which of three conventions you keep the books in.

System. Hoxha, Passer and Habert — Guillaume Habert holds ETH Zurich’s Chair of Sustainable Construction — name those three in Buildings & Cities (2020, doi:10.5334/bc.46). Under 0/0, my 1,480 t is invisible: uptake and end-of-life release cancel. Under −1/+1, it is a loan — credited when I am built, repaid in module C when I am demolished. Under a dynamic method, it is a time-weighted quantity that can land on either side depending on when the plantation is booked as regrowing. Their own Graz case diverged 16% between methods at building scale, and the dynamic variant counting regrowth after construction came out 29% higher — worse for the timber, not better. Time-aware accounting is not a subsidy for my body. It moves the number in both directions.

←TODAY: A Zurich desk can add the convention line — method, reference study period, modules — to a live SIA 2032 statement this week. →3012: The buildings that survive are the ones whose ledgers were honest about which loan was still open. Fulcrum: A single biogenic figure yields three honest answers; the number is only as real as the convention printed beside it.

Street. New Zealand’s own methodology does not net the way my marketing does. MBIE’s Whole-of-Life Embodied Carbon Assessment (February 2022, a proposed guide resting on EN 15978 and EN 16485:2014) says removals “shall always be reported separately to emissions.” Switzerland agrees: KBOB’s Ökobilanzdaten V9.0 reports biogenic carbon separately, in kilograms of carbon, never folded into a headline. So “1,089 ahead” is my client’s format, not the method’s — and I would rather you knew that than clicked past it.

Building-sense: I am stiff by geometry and forgiving by detail — my pātiki diamonds do not bend, my sacrificial steel connectors do, and then they are swapped. Scion says its testing on the Rotorua demonstrator found a test building’s pre-earthquake strength “would be restored by simply replacing the steel connectors” while the timber “remained intact.” A fuse in wood, inherited from Te Whare Nui o Tuteata. I would rather be dismantled than demolished.

Atelier: The deliverable this week is not admiration — it is the convention line on your own LCA statement. A timber carbon claim without method (0/0, −1/+1, dynamic), reference study period, and module scope is a headline, not a number. Monday move: on the sheet that carries your timber take-off in m³, add one row — “biogenic reported separately (KBOB), method: ___, RSP: ___ yr, modules: ___” — and refuse to sign a netted figure until those three blanks are filled.

Hack: Run my ledger under all three conventions and watch one input become four answers. The point is not which is true; it is that honesty means printing the rule beside the result.

bio, emis, rsp, H = 1480, 391, 50, 100  # 391 t = 1480 - 1089, upfront floor
print("0/0        :", emis)              # +391: biogenic ignored
print("upfront    :", emis - bio)        # -1089: the published claim
print("whole-life :", emis - bio + bio)  # +391: loan repaid at demolition
print("time-weight:", round(emis - bio * rsp / H))  # ~-349, illustrative only

Fisher & Paykel, RTA Studio, Naylor Love and Red Stag TimberLab did the rarer thing: they published a number at all. Aim your scepticism at the convention, never at the builder. Before you pour or print anything, ask the one question my generation learned too late — when this body dies, can it be taken apart? Choose materials your grandchildren can disassemble.