Effects on Carbon Storage of Conversion of Old-Growth Forests to Young Forests

TLDR

Simulations suggest that converting old‑growth forests to young fast‑growing forests does not generally reduce atmospheric CO₂, contrary to recent claims. The study aims to determine how much lumber production and building lifespan would need to increase to offset this effect. Mass‑balance calculations were used to estimate that 5 × 10⁹ to 1.8 × 10⁹ megagrams of carbon would be released into the atmosphere. Simulated timber harvest markedly reduces on‑site carbon storage for at least 200 years, and even when building sequestration is included, it produces a net CO₂ flux, with mass‑balance estimates indicating 5 × 10⁹ to 1.8 × 10⁹ megagrams of carbon released.

Abstract

Simulations of carbon storage suggest that conversion of old-growth forests to young fast-growing forests will not decrease atmospheric carbon dioxide (CO(2)) in general, as has been suggested recently. During simulated timber harvest, on-site carbon storage is reduced considerably and does not approach old-growth storage capacity for at least 200 years. Even when sequestration of carbon in wooden buildings is included in the models, timber harvest results in a net flux of CO(2) to the atmosphere. To offset this effect, the production of lumber and other long-term wood products, as well as the life-span of buildings, would have to increase markedly. Mass balance calculations indicate that the conversion of 5 x 10(9) to 1.8 x 10(9) megagrams of carbon to the atmosphere.