Biomass carbon per hectare in New Zealand forests

Forest carbon stocks include the amount of carbon stored in living and dead forest biomass (including trunk, roots, branches, deadwood, and litter) and in soil.
Deforestation is the change from forest to an alternative land use. Managed forest land that is harvested does not count as deforestation if it is replanted and used for the same purpose. However, if the managed forest land is harvested and used for another purpose it is counted as deforested area.

http://www.mfe.govt.nz/sites/default/files/media/Climate%20Change/FINAL%20GHG%20inventory%20-%2025%20May.pdf

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New Zealand’s indigenous and exotic forests absorb carbon dioxide (CO2) from the atmosphere through photosynthesis and store the carbon as biomass and in the soil. On average, more than twice as much carbon per hectare is stored in New Zealand’s mature indigenous forests than in exotic forests planted for wood production. Regenerating indigenous forests are also an important store of carbon, adding carbon every year as they grow. Total carbon stored in exotic forests will fluctuate over decades as the forests grow from seedlings to mature trees, are harvested, and replanted. Because CO2 is the major driver of climate change, forests provide important mitigation services and help New Zealand meet its climate change commitments.

The Ministry for the Environment uses its Land Use Carbon Analysis System (LUCAS) to calculate the amount of carbon stored in each forest, through modelling and from field measurements at a network of forest plots across New Zealand. Land-use maps created from satellite imagery determine the area of each forest type. Data collection of forest carbon stocks started in 1990 because of the need to account for the amount of carbon as set forth in the Kyoto Protocol.