Table 1.

Variable definitions for the IPCC/EPA production accounting approach shown in Figure 2 [3]. Units for all variables are MgC yr^-1.

Variable	Definition
ΔS	Annual carbon stock change for the total forest sector, which is calculated as ΔS = (NEE-H)+(ΔCR1) in the production accounting approach.
NEE	Annual net ecosystem carbon exchange, the annual net carbon that moves from the atmosphere to forests.
H	Annual harvest of wood for products, which includes wood and residues removed from harvest sites, but excludes resides left at harvest sites.
HWP	Harvested wood products in use or at solid waste disposal sites.
ER1	Annual emission of carbon to the atmosphere in the Northern Region from products made from wood harvested in the Northern Region.
EIM	Annual emission of carbon to the atmosphere in the Northern Region from products made from wood harvested outside of the Northern Region and imported into The Northern Region.
PEX	Annual exports of wood and paper products out of the Northern Region, including roundwood, chips, residue, pulp and recovered (recycled) products.
PIM	Annual imports of wood and paper products into the Northern Region, including roundwood, chips, residue, pulp and recovered (recycled) products.
EEX R1	Annual emission of carbon to the atmosphere in areas outside of the Northern Region from products made from wood harvested in the Northern Region.
EOTHER	Annual emission of carbon to the atmosphere in areas outside of the Northern Region from products made from wood harvested outside the Northern Region.
CR1	Stock of harvested wood products carbon in use or at solid waste disposal sites where products used wood from the Northern Region harvests.
ΔCIU R1	Annual change in carbon stored in harvested wood products in products in use where products used wood from the Northern Region harvests.
ΔCSWDS R1	Annual change in carbon stored in harvested wood products at solid waste disposal sites where products used wood from the Northern Region harvests.
ΔCR1	Annual change in carbon stored in harvested wood products in products in use and at solid waste disposal sites where products used wood from the Northern Region harvests. ΔCR1 = ΔCIU R1 + ΔCSWDS R1