Strategies to mitigate carbon dioxide emissions through forestry
activities have been proposed, but ecosystem process-based integration
of climate change, enhanced CO2, disturbance from fire,
and management actions at regional scales are extremely limited.
Here, we examine the relative merits of afforestation, reforestation,
management changes, and harvest residue bioenergy use in
the Pacific Northwest. This region represents some of the highest
carbon density forests in the world, which can store carbon in
trees for 800 y or more. Oregon’s net ecosystem carbon balance
(NECB) was equivalent to 72% of total emissions in 2011–2015. By
2100, simulations show increased net carbon uptake with little
change in wildfires. Reforestation, afforestation, lengthened harvest
cycles on private lands, and restricting harvest on public lands
increase NECB 56% by 2100, with the latter two actions contributing
the most. Resultant cobenefits included water availability and
biodiversity, primarily from increased forest area, age, and species
diversity. Converting 127,000 ha of irrigated grass crops to native
forests could decrease irrigation demand by 233 billion m3·y−1.
Utilizing harvest residues for bioenergy production instead of leaving
them in forests to decompose increased emissions in the shortterm
(50 y), reducing mitigation effectiveness. Increasing forest carbon
on public lands reduced emissions compared with storage in wood
products because the residence time is more than twice that of wood
products. Hence, temperate forests with high carbon densities and
lower vulnerability to mortality have substantial potential for reducing
forest sector emissions. Our analysis framework provides a template
for assessments in other temperate regions.
